A square is 100 square feet of roof surface. Roofers measure and price in squares, so a 25-square roof has about 2,500 square feet of surface. Roof area is always larger than the home’s footprint because of slope and overhangs; multiply the footprint by the slope factor (about 1.118 for a 6/12 roof) to estimate it, or use the roof area calculator.
Roofing Glossary
Roofing Glossary: 275+ Roofing and Gutter Terms in Plain English
Estimates, insurance paperwork and inspection reports are full of words nobody explains. This glossary defines 276 of them in plain English, from drip edge and step flashing to recoverable depreciation, hurricane deductibles and K-style gutters, for Midlands homeowners, property managers and anyone comparing roofing bids.
Start here
How to use this glossary
Terms are listed A to Z. Use the letter bar to jump, or your browser’s find (Ctrl+F or Cmd+F) to search the page. Every term has its own link, so you can send someone straight to one definition, for example /guide/roofing-glossary/#drip-edge.
The glossary covers steep-slope residential roofs (shingles, flashing, underlayment, ventilation and decking), low-slope and commercial systems (TPO, EPDM, PVC, modified bitumen, built-up roofs and coatings), metal, gutters and downspouts, how roofs are measured, what estimate and contract terms mean, insurance claim vocabulary, and the South Carolina rules and Midlands weather that shape roofs here.
Code references are to the International Residential Code as adopted in South Carolina. Your local building department has the final word on what applies to your project.
Insurance, lien and contract definitions here are general information, not legal, insurance or tax advice. Your policy and contract language control; for a specific situation, talk to your agent, adjuster or an attorney.
Mix-ups
The most-confused roofing terms
These pairs trip up homeowners, and sometimes the estimates they receive. Knowing the difference makes it much easier to compare bids and read an insurance scope.
Drip edge vs. Gutter apron
Both are metal at the roof edge. Drip edge is an L- or T-shaped strip that kicks water away from the fascia; South Carolina’s code requires it on shingle roofs where the manufacturer does, and the major manufacturers do. Gutter apron is shaped to reach down into the gutter so water cannot sneak behind it. At the eaves a roofer uses one or the other depending on the gutters; rakes always get drip edge.
Underlayment vs. Ice and water shield
Underlayment is the general backup layer over the whole deck, usually a synthetic sheet that is nailed down and sheds water. Ice and water shield is a self-adhered membrane that sticks to the deck and seals around nails, used where water concentrates or can back up: valleys, around chimneys and skylights, and at low-slope transitions.
Soft washing vs. Algae streaks
Algae streaks are the problem: dark stains from Gloeocapsa magma feeding on the shingle surface, everywhere in the humid Midlands. Soft washing is the fix: a low-pressure cleaning solution that kills the growth and lets rain rinse it off. Pressure washing is not the fix; it strips granules.
Actual cash value (ACV) vs. Replacement cost value (RCV)
RCV is what it costs to replace the roof new today. ACV is RCV minus depreciation. On an RCV policy you usually get the ACV check first and the held-back depreciation after the work is done. On an ACV policy, or where the policy pays roofs at ACV, that depreciation is gone for good.
Deductible vs. Hurricane deductible
The regular deductible is usually a flat dollar amount. Many South Carolina policies add a separate hurricane, named storm or wind and hail deductible, often a percentage of the dwelling coverage, which can be several times larger. Which one applies depends on what caused the damage.
Roof-over vs. Tear-off
A roof-over installs new shingles over the old layer; a tear-off strips to the deck first. The code bans a roof-over when there are already two layers or the existing roof or deck is deteriorated. A tear-off costs more up front but lets the crew see and fix the deck, flashing and ventilation.
Soffit vs. Fascia
Fascia is the vertical board along the roof edge that the gutter hangs on. Soffit is the horizontal underside of the overhang, between the fascia and the wall. Soffit vents are the attic’s intake; fascia is trim, and the board that rots when gutters overflow.
K-style gutter vs. Half-round gutter
K-style has a flat back and a decorative front and carries more water for its width, which is why it is the Midlands default. Half-round is a semicircle, sheds debris well and suits historic homes, but a 6-inch half-round carries far less than a 6-inch K-style.
Manufacturer warranty vs. Workmanship warranty
The manufacturer warranty covers defects in the material and, on enhanced system warranties, some labor. The workmanship warranty is the roofer’s own promise on the installation. Most roof failures are installation-related, so the workmanship warranty and the company behind it matter as much as the shingle brand.
Residential specialty contractor vs. Residential builder license
Both can legally replace a roof on a South Carolina home. A roofer is usually a registered residential specialty contractor: no exam, required above $500. A residential builder is licensed by exam for jobs over $5,000 and may do roofing without a separate registration. Check either one on the LLR lookup.
Public adjuster vs. Adjuster
The adjuster works for, or is hired by, your insurance company. A public adjuster works for you, is licensed by the SC Department of Insurance, and in South Carolina may charge no more than 10 percent of the settlement. A roofer is neither and may not negotiate your roof claim.
Mechanic’s lien vs. Lien waiver
A mechanic’s lien is a claim an unpaid contractor or supplier can file against your property within 90 days of their last work. A lien waiver, or release, is their signed statement that they have been paid and give up that right. You collect waivers so you never face a lien after paying in full.
Quick reference
Roofing by the numbers
The figures that come up most often in estimates, inspection reports and code discussions, with where each one comes from.
| Term | The number | What it means |
|---|---|---|
| Square | 100 sq ft of roof surface | A 25-square roof is about 2,500 sq ft of roof surface, not floor area. |
| Bundle | Often 3 per square | Common for architectural shingles; heavier products may take 4 or more. |
| Slope factor, 4/12 | about 1.054 | Multiply the flat footprint by this to get sloped roof area. |
| Slope factor, 6/12 | about 1.118 | A 2,000 sq ft footprint at 6/12 is about 2,236 sq ft of roof. |
| Slope factor, 8/12 | about 1.202 | Steeper roofs have noticeably more surface than their footprint. |
| Slope factor, 12/12 | about 1.414 | A 45-degree roof: about 41 percent more surface than footprint. |
| Waste factor | roughly 10% and up | Around 10 percent on simple gables, more on hips and cut-up roofs. |
| Minimum shingle slope | 2 in 12 | From 2/12 up to 4/12, the code requires two layers of underlayment (IRC R905.2.2). |
| Membrane roofs | 1/4 in 12 | Minimum design slope for drainage on TPO, EPDM, modified bitumen and built-up roofs. |
| Attic ventilation | 1/150 (1/300 in some cases) | Net free vent area per sq ft of attic floor (IRC R806.2). |
| Layer limit | 2 layers | No new roof over two existing layers (IRC R908.3.1.1). |
| Drip edge laps | 2 inches | Minimum overlap where drip edge pieces meet (IRC R905.2.8.5; in SC, drip edge itself is required where the manufacturer requires it). |
| Chimney cricket | wider than 30 in. | Chimneys wider than 30 inches that do not sit on the ridge need a cricket. |
| Class 4 impact (UL 2218) | 2 in. steel ball | The highest impact rating for roof coverings. |
| Wind, ASTM D3161 Class F | 110 mph | Older fan-based shingle wind test. |
| Wind, ASTM D7158 Class H | 150 mph | Newer uplift-based shingle wind test. |
| Hurricane season | June 1 to November 30 | The Atlantic season the National Hurricane Center tracks. |
| SC roofer registration | jobs over $500 | Residential specialty contractor registration with the Residential Builders Commission. |
| SC commercial license | jobs over $10,000 | Contractor’s Licensing Board license for general contracting. |
| Mechanic’s lien deadline | 90 days | From the last day of work or materials to serve and file a lien in SC. |
| Door-to-door cancel | 3 business days | FTC Cooling-Off Rule for sales of $25 or more made at your home. |
| Insurance-denial cancel | 5 business days | SC right to cancel a roofing contract after a written insurance denial. |
| Public adjuster fee cap | 10 percent | Maximum share of an insurance settlement a SC public adjuster may charge. |
Want to run the math on your own roof? The roofing calculators handle squares, pitch, materials, ventilation and gutter sizing.
A to Z
The roofing glossary
- Acrylic Roof Coating
- A water-based elastomeric coating rolled or sprayed over an existing low-slope roof to add reflectivity and a new weathering surface. It is economical and bright white, but it generally tolerates standing water less well than silicone, so it suits roofs that drain well.
- See also: Roof coatings, Silicone Roof Coating, Ponding Water
- Actual Cash Value (ACV)
- Also called: ACV
- An insurance settlement basis: the cost to replace the damaged roof minus depreciation for its age and wear. On an ACV policy or endorsement, the depreciation is not paid back later, so an older roof can produce a much smaller check than the cost of the new roof.
- See also: Replacement Cost Value (RCV), Depreciation, Roof insurance claims guide
- Adjuster
- Also called: Insurance adjuster, field adjuster, desk adjuster
- The person who investigates a claim and decides what the policy pays. A staff adjuster works for the insurer, an independent adjuster is hired by the insurer on contract (common after big storms), and a desk adjuster reviews photos and estimates without visiting.
- See also: Public Adjuster, Reinspection, The roof insurance claim process
- Aerial Measurement Report
- A roof measurement produced from satellite or aerial imagery that lists squares, pitches and linear feet of ridges, valleys, eaves and rakes. It is a solid starting point, but trees, recent additions and multiple layers can throw it off, so a good estimator still checks it on site.
- See also: Square, Linear Foot, Roofing calculators
- Aggregate
- Gravel or crushed stone embedded in or laid over a low-slope roof, most often the top surface of a built-up (tar and gravel) roof or the ballast on a loose-laid membrane. It shields the membrane from sunlight and adds weight against wind.
- See also: Built-Up Roofing (BUR), Ballast
- Algae Streaks
- The black or dark-green streaks common on shaded and north-facing shingle slopes, caused by airborne algae (usually Gloeocapsa magma) feeding on the limestone filler in shingles. They are very common in the humid Midlands and mostly cosmetic at first. Many shingles now carry algae-resistant granules that contain copper, and a low-pressure soft wash removes existing streaks without stripping granules. Never pressure wash a shingle roof.
- See also: Soft Washing, Gloeocapsa Magma, Moss, Roof soft washing
- Algae-Resistant Shingle
- Also called: AR shingle, StainGuard, Scotchgard-protected
- A shingle with some copper-containing granules mixed in to slow algae growth. Manufacturers back the feature with a separate, time-limited algae warranty. In humid Midlands neighborhoods with tree cover it is worth asking for by name.
- See also: Algae Streaks, Granules
- Alligatoring
- A pattern of deep cracks that looks like alligator hide, found on aged asphalt surfaces such as built-up roofs, old roll roofing and worn coatings. It means the asphalt has dried out and lost flexibility, and water can soon reach the layers underneath.
- See also: Built-Up Roofing (BUR), Flat roof repair vs. replacement
- Allowance
- A contract line that sets aside a budgeted amount for something that cannot be priced until the job is underway, such as replacing rotted decking. Read how an allowance is reconciled: whether unused money is credited back and what happens if the real cost goes over.
- See also: Unit Price, Change Order, How to read a roofing estimate
- Appraisal Clause
- A provision in most homeowners policies that lets either side demand an independent appraisal when you and the insurer agree the damage is covered but disagree on the dollar amount. Each side hires an appraiser and an umpire settles disputes. It resolves price, not whether something is covered.
- See also: Supplement, The roof insurance claim process
- Apron Flashing
- Also called: Headwall flashing, front flashing
- A continuous piece of metal flashing where the top of a lower roof meets a vertical wall or the downhill face of a chimney. It laps over the shingles below and runs up the wall behind the siding or under counterflashing.
- See also: Step Flashing, Counterflashing, Chimney flashing
- Architectural Shingle
- Also called: Dimensional shingle, laminated shingle
- The most common residential shingle today. Two or more layers are laminated together to give a thicker, shadowed look, and they are heavier and generally longer-rated than three-tab shingles. Because of that layered profile, laying new shingles over them flat is very hard to do well.
- See also: Three-Tab Shingle, Asphalt shingle roofing
- Asphalt Shingle
- Also called: Composition shingle, comp shingle
- A roofing shingle made of a fiberglass mat coated with asphalt and topped with ceramic-coated mineral granules. It is the most common roof on Midlands homes because it balances cost, looks and service life. Summer heat is what ages it here: long stretches of strong sun dry out the asphalt and loosen granules over time.
- See also: Asphalt shingle roofing, Architectural Shingle, How long roofs last in Columbia
- Assignment of Benefits
- Also called: AOB
- A document that signs over your right to insurance payments on a claim to someone else, such as a contractor, so they can bill the insurer directly. Under a 2026 South Carolina law, a policy may prohibit assigning benefits to a property repair contractor, and contractors may not use a power of attorney to get around public adjuster licensing. Read anything a roofer asks you to sign about your claim carefully. General information, not legal advice.
- See also: Public Adjuster, Insurance Denial Cancellation, Roof insurance claims guide
- Attic Air Bypass
- Also called: Attic air leak
- Any gap that lets warm, moist house air leak into the attic: around recessed lights, plumbing stacks, bath fans, chimneys, attic hatches and top plates. Bypasses are a leading cause of ice dams, attic frost and mold, and sealing them often matters as much as adding vents.
- See also: Ice Dam, Attic Frost, Moisture and mold prevention
- Attic Frost
- Frost that builds up on the underside of the roof deck and on nail tips on cold nights, from moist indoor air reaching a cold attic. It is uncommon in the Midlands but does happen during winter cold snaps in poorly sealed attics. When it melts it drips all at once, which homeowners often mistake for a roof leak.
- See also: Attic Air Bypass, Ventilation, Roof ventilation guide
- Baffle
- Also called: Rafter vent, insulation baffle
- A channel of foam, cardboard or plastic stapled between rafters at the eaves that keeps attic insulation from blocking the soffit vents. Without baffles, blown insulation often seals off the intake air and ventilation stops working.
- See also: Soffit Vent, Intake Vent, Roof ventilation guide
- Ballast
- Weight, usually river rock or concrete pavers, that holds a loose-laid single-ply membrane in place instead of fasteners or adhesive. A ballasted roof has to be structurally able to carry the extra load, and the stones must be moved to find or repair a leak.
- See also: Mechanically Attached, Fully Adhered, Commercial roofing guide
- Base Flashing
- On a low-slope roof, the membrane that turns up from the roof surface onto a wall, curb or parapet to seal that joint. It is usually covered at the top by counterflashing or a termination bar so water cannot run behind it.
- See also: Counterflashing, Termination Bar, Parapet
- Base Sheet
- The first ply laid on a low-slope deck in a built-up or modified bitumen system. It is fastened or adhered to the deck, and the remaining plies and the cap sheet are bonded on top of it.
- See also: Cap Sheet, Modified Bitumen, Built-Up Roofing (BUR)
- Batten
- A wood or metal strip fastened across the roof that some coverings, including many tile, slate and some metal systems, hang from or fasten to. Battens can also create a small air space under the roof covering.
- See also: Roofing materials guide, Roofing materials guide
- Blistering
- Raised bubbles in a roof surface. On shingles, small blisters usually come from moisture or gases trapped during manufacturing and are made worse by heat, which is why they show up on sun-baked Midlands slopes; when they pop they leave bare spots. On membranes and built-up roofs, blisters are pockets of trapped air or moisture between layers that can split open.
- See also: Granule Loss, UV and heat roof damage
- Blow-Off
- Shingles that wind has torn loose and carried away, often along an edge, ridge or rake where uplift is strongest. Blow-offs are frequently traced to shingles that never sealed, or to nails driven above the nail line.
- See also: High Nailing, Sealant Strip, Wind damage guide, Wind damage guide
- Box Vent
- Also called: Static vent, turtle vent, louver vent
- A low, square exhaust vent with no moving parts, installed near the ridge in groups. Box vents let warm attic air escape by natural convection and are common where a continuous ridge vent is not practical.
- See also: Ridge Vent, Exhaust Vent, Power Vent
- Buckling
- Wavy, raised lines running across a shingle roof. It usually traces back to the deck or underlayment moving: swelling sheathing, wrinkled felt that got wet before shingling, or decking that was installed without spacing gaps.
- See also: Deck, Felt Underlayment
- Building Permit
- Also called: Roofing permit
- Written approval from the local building department to do the work, followed by one or more inspections. South Carolina law requires the permit office to see proof that the contractor is licensed or registered before it issues a residential permit, which is one reason the contractor, not the homeowner, usually pulls it. Whether a straight reroof needs a permit depends on the city or county, so ask your building department or have the roofer show you the permit.
- See also: Final Inspection, South Carolina Residential Code, Roof permits in South Carolina
- Built-Up Roofing (BUR)
- Also called: Tar and gravel roof
- A traditional low-slope system of alternating layers of roofing felt and hot or cold asphalt (or coal tar), usually finished with a layer of gravel. It is heavy and redundant, but it is labor-intensive and has largely given way to single-ply and modified bitumen systems.
- See also: Aggregate, Modified Bitumen, Commercial roofing guide
- Bundle
- The package shingles are sold in. Many common architectural shingles come three bundles to a square (100 square feet of coverage), but some heavier products take four or more, so check the wrapper rather than assume.
- See also: Square, Roofing calculators
- Butyl Tape
- A sticky, rubbery sealing tape used in metal roofing laps, flashings and some membrane details. It stays flexible for years and seals out water where two pieces of material overlap.
- See also: Standing Seam, Exposed-Fastener Metal Roof
- Cant Strip
- A triangular strip, often wood fiber or perlite, set in the 90-degree corner where a low-slope roof meets a wall. It softens the bend so the membrane or felt does not have to make a sharp fold that can crack.
- See also: Base Flashing, Built-Up Roofing (BUR)
- Cap Nail
- Also called: Plastic cap nail
- A roofing nail with a wide plastic or metal washer under the head, used to fasten underlayment. The wide head holds synthetic underlayment down in wind far better than a bare nail or staple.
- See also: Synthetic Underlayment, Underlayment
- Cap Sheet
- The top, weather-exposed ply of a modified bitumen or built-up roof, usually surfaced with mineral granules for protection from sunlight.
- See also: Base Sheet, Modified Bitumen
- Certificate of Insurance (COI)
- Also called: COI
- A one-page document from a contractor’s insurance agent showing their general liability and workers’ compensation coverage, limits and dates. South Carolina law does not require residential roofers to carry general liability, so asking for the certificate is the only way to know. Have it sent directly from the agent, and check that the named business matches your contract.
- See also: Workers' Compensation, How to hire a roofer in South Carolina, Roofing questions and answers
- Change Order
- A signed, written amendment to a roofing contract that changes the scope, price or schedule after work starts, for example extra decking or a code-required item that was not in the original bid. Get it in writing, with the price, before the extra work is done.
- See also: Allowance, Unit Price, How to read a roofing estimate
- Chimney Cricket
- Also called: Chimney saddle
- A small peaked roof built on the uphill side of a chimney to split water and snow around it instead of letting them pile against the back. The residential code requires one behind chimneys wider than 30 inches that do not sit on the ridge.
- See also: Cricket, Counterflashing, Chimney flashing
- Class 4 Impact Rating
- The highest impact rating under the UL 2218 test, meaning a sample withstood a 2-inch steel ball dropped from 20 feet without cracking. Impact-rated shingles can resist hail better, and some insurers discount premiums for them. Class 4 does not mean hail-proof, and it is not a wind rating.
- See also: Impact-Resistant Shingle, Wind Rating, Hail damage in Columbia
- Class A Fire Rating
- The highest fire-resistance classification for roof coverings under the UL 790 / ASTM E108 test, which measures how the roof resists fire from outside, such as embers. Most asphalt shingles, metal, slate and tile carry Class A ratings, sometimes only when installed over a specified underlayment.
- See also: Roofing materials guide
- Closed-Cut Valley
- A valley where shingles from one slope run through the valley and shingles from the other slope are laid over them and cut in a straight line a couple of inches from the center. It is the most common asphalt valley style today.
- See also: Valley, Open Valley, Woven Valley
- Collar Tie
- A horizontal board that connects opposing rafters in the upper part of the attic. It helps hold the roof framing together against wind and uneven loads.
- See also: Rafter, Rotten roof decking
- Condensation
- Water that forms when warm, moist air hits a cold surface. In a roof, it shows up as damp sheathing, rusty nail tips, drips or mold in the attic, and it is usually a ventilation, air sealing or bathroom-fan venting problem rather than a roof leak.
- See also: Attic Frost, Vapor Retarder, Moisture and mold prevention
- Contractor’s Licensing Board
- Also called: CLB
- The South Carolina board that licenses general and mechanical contractors for commercial work. A license is required when a job’s total cost is over $10,000 (raised from $5,000 in 2023), roofing is one of the specialty classifications, and license groups cap how large a job the holder may take. The contractor must use the exact licensed name in ads and contracts.
- See also: SC LLR, Commercial roofing guide
- Cool Roof
- A roof surface designed to reflect more sunlight and give off absorbed heat, lowering roof temperature. It pays off most on flat commercial roofs with large cooling loads, which in Columbia’s long cooling season can be significant. On a shingled house the effect is smaller, and attic ventilation and insulation matter more. The ENERGY STAR label for roof products ended in 2022.
- See also: Solar Reflectance, Radiant Barrier, Energy-efficient roofing
- Coping
- Also called: Coping cap
- The metal (or stone) cap over the top of a parapet wall that seals the top and sheds water to both sides. Loose or poorly seamed coping is a common source of commercial roof leaks.
- See also: Parapet, Edge Metal
- Core Cut
- Also called: Core sample
- A small plug cut through a low-slope roof to see what is actually there: how many roofs, what insulation, whether it is wet, and what the deck is. It is patched immediately afterward and is the only sure way to decide between recover and tear-off.
- See also: Infrared Moisture Survey, Recover Board, Commercial roofing guide
- Counterflashing
- Also called: Cap flashing
- Metal flashing set into or fastened to a wall or chimney that laps down over the base or step flashing below it. The two pieces work together so the joint can move without opening a gap. On masonry it is typically set into a cut mortar joint or reglet.
- See also: Step Flashing, Reglet, Roof repair
- Course
- A single horizontal row of shingles, slates or tiles running across the roof.
- See also: Exposure, Starter Strip
- Cover Board
- A thin, stiff board (gypsum, high-density polyiso or wood fiber) placed on top of the insulation under a low-slope membrane. It spreads out foot traffic and hail impacts and gives the membrane a smooth, stable surface.
- See also: Polyiso, Recover Board
- Crease
- Also called: Creased shingle
- A horizontal fold line across a shingle where wind lifted and bent it back. A creased shingle has lost strength and usually its seal, and it counts as wind damage even if it has settled back down.
- See also: Wind Damage, Sealant Strip
- Cricket
- On a low-slope roof, a small sloped build-up (usually tapered insulation) that diverts water around a curb or toward a drain instead of letting it pond. On a house it most often means the saddle behind a chimney.
- See also: Chimney Cricket, Tapered Insulation, Ponding Water
- Curb
- A raised frame on the roof that a skylight, rooftop unit, hatch or fan sits on, flashed on all four sides. Curbs lift the opening above the water line and are a frequent leak point on commercial roofs.
- See also: Base Flashing, Skylight leaks
- Curling
- Also called: Cupping, clawing
- Shingle edges lifting up (cupping) or corners turning down (clawing) as a shingle ages, loses oils or is overheated by a poorly vented attic. Widespread curling is a classic end-of-life sign.
- See also: How long roofs last in Columbia, Roof ventilation guide
- Date of Loss
- The date the storm or event that caused the damage happened. Insurers use it to confirm the policy was in force and to check deadlines for reporting a claim, so note it and keep weather reports or photos.
- See also: Proof of Loss, Storm damage roofing guide
- Dead Valley
- A spot where two roof planes meet in a way that water and snow cannot drain out easily, such as behind a chimney or where a dormer wall meets a roof. Dead valleys collect debris and ice and need extra ice barrier and careful flashing.
- See also: Cricket, Ice Barrier
- Deck
- Also called: Roof deck, sheathing, decking
- The structural surface the roof is fastened to: plywood or OSB on most homes, older plank boards on many pre-1970 houses, and steel, concrete or wood on commercial buildings. Soft, rotted or delaminated decking has to be replaced before a new roof goes on.
- See also: OSB, Plank Decking, Rotten roof decking
- Deductible
- The portion of a covered loss you pay before insurance pays. Some policies use a flat dollar deductible, and many South Carolina policies add a separate, larger deductible for hurricane, named storm or wind and hail damage, often a percentage of the dwelling coverage. It is your share. In South Carolina a roofer may not pay, rebate or discount it, including through a "yard sign" credit (S.C. Code § 40-59-25).
- See also: Hurricane Deductible, Deductible Rebating, Roof insurance claims guide
- Deductible Rebating
- A contractor paying, waiving or discounting your insurance deductible to win the job, including "sign in the yard" credits, referral fees or gift cards that come off the price. In South Carolina it is a misdemeanor for the contractor and grounds for losing their license (S.C. Code § 40-59-25). A bid that is exactly the insurance payout with no deductible is the same thing. General information, not legal advice.
- See also: Deductible, Insurance Fraud, How to hire a roofer in South Carolina
- Delamination
- Layers separating that should stay bonded: plies of plywood or OSB coming apart from moisture, laminated shingle layers separating, or a membrane peeling from insulation.
- See also: Deck, OSB
- Deposit
- Money paid up front, often to order materials. South Carolina has no general cap on roofing deposits, so the amount is whatever the contract says. A reasonable deposit tied to a clear schedule is normal; paying most of the job before work starts gives you little leverage. On insurance-funded roof jobs, a contractor may not require any payment until your five-business-day cancellation window has passed (S.C. Code § 40-59-25).
- See also: Insurance Denial Cancellation, How to hire a roofer in South Carolina
- Depreciation
- The amount an insurer subtracts from replacement cost for age and wear. On a replacement cost policy much of it is usually recoverable after the work is finished. On an actual cash value policy it is not.
- See also: Recoverable Depreciation, Non-Recoverable Depreciation, Actual Cash Value (ACV)
- Detach and Reset (D&R)
- Also called: D&R, remove and reinstall (R&R)
- An estimate line for removing an item so roofing can be done, then putting it back: satellite dishes, solar panels, gutters, snow guards, antennas. In insurance estimates, R&R usually means remove and replace, while D&R means remove and put the same item back.
- See also: Line Item, Xactimate, How to read a roofing estimate
- Dimensional Shingle
- Another name for an architectural (laminated) shingle.
- See also: Architectural Shingle
- Dormer
- A structure that projects out of a sloped roof with its own small roof and a vertical wall, usually holding a window. Dormers add step flashing, valleys and small roof-to-wall joints, which is where many residential leaks start.
- See also: Step Flashing, Kick-Out Flashing
- Downspout
- Also called: Leader, conductor
- The vertical pipe that carries water from a gutter to the ground or a drain. Common residential sizes are 2 x 3 and 3 x 4 inch rectangular, and 3 or 4 inch round. Downspouts should discharge several feet away from the foundation, never onto a lower roof without a diverter, and never into a spot where water runs back toward the house.
- See also: Downspout Extension, Splash Block, Why downspout placement matters, Roofing calculators
- Downspout Extension
- A length of pipe, flexible tube, or buried line that carries water from the bottom of a downspout away from the foundation. Moving discharge several feet from the house is one of the simplest fixes for wet crawl spaces and basements.
- See also: Downspout, Splash Block, How gutters protect your foundation
- Drip Edge
- An L- or T-shaped metal strip along the eaves and rakes that directs water off the roof edge and away from the fascia, and closes the gap between deck and fascia. The national model code requires it on asphalt shingle roofs; South Carolina’s amendment requires it where the shingle manufacturer does, and the major manufacturers’ installation instructions call for it. Either way, a roof without it is a roof to ask about.
- See also: Gutter Apron, Rake, Eave
- Dry-In
- The point at which the deck is covered with underlayment and flashings so the building is protected from rain, even though the final roof covering is not on yet. A good crew only tears off what it can dry in the same day.
- See also: Underlayment, Tear-Off
- Eave
- The lower, horizontal edge of a roof slope that overhangs the wall, where water runs off into the gutter. The eave is where ice dams form, which is why ice barrier starts there.
- See also: Ice Barrier, Soffit, Fascia
- Edge Metal
- Also called: Gravel stop, roof edge
- The metal trim along the perimeter of a low-slope roof that holds the membrane edge down and finishes it. Because wind uplift starts at the edge, commercial edge metal is typically tested to the ANSI/SPRI ES-1 standard.
- See also: Coping, Uplift, Commercial roofing guide
- Elastomeric
- Rubber-like: able to stretch and recover. Elastomeric roof coatings (acrylic, silicone, urethane) and membranes flex with the roof as it heats, cools and moves without cracking.
- See also: Acrylic Roof Coating, Silicone Roof Coating
- EPDM
- Also called: Rubber roof
- Ethylene propylene diene monomer, a black synthetic rubber single-ply membrane for low-slope roofs. It is durable, flexible in cold and has a long track record, with seams joined by tape and adhesive rather than heat welding.
- See also: Commercial roofing, TPO, Thermoset vs. Thermoplastic
- Estimate
- Also called: Bid, proposal, quote
- A contractor's written price and scope for the job. A useful roofing estimate lists materials by product line, what is torn off, underlayment and ice barrier coverage, flashing, ventilation, decking pricing, cleanup, permit and warranty, so you can compare bids line by line.
- See also: Scope of Work, Line Item, How to read a roofing estimate
- Exhaust Vent
- A vent high on the roof, such as a ridge vent, box vent or gable vent, that lets warm, moist air leave the attic. It only works if there is matching intake low on the roof.
- See also: Intake Vent, Ventilation, Ridge Vent
- Expansion Joint
- A flexible joint in a roof, usually on larger commercial buildings, that lets separate sections move without tearing the membrane. It needs its own flashing and cover.
- See also: Commercial roofing guide
- Exposed Nail
- A nail head left uncovered by the next course or at ridge cap, often sealed with a dab of sealant. Exposed nails that are not sealed are a leak and rust point.
- See also: Nail Pop, Ridge Cap
- Exposed-Fastener Metal Roof
- Also called: Screw-down panel, ag panel, R-panel
- Metal panels fastened through the face with gasketed screws. They cost less than standing seam, but the rubber washers on thousands of screws age and need periodic checking or replacement, and the panels cannot move freely with temperature.
- See also: Standing Seam, Metal roofing, Roof costs by material
- Fascia
- The vertical trim board along the roof edge at the eaves, where gutters are usually attached. It is part of the house trim, not the roof itself, and it rots when water gets behind the gutter or drip edge.
- See also: Soffit, Drip Edge, Gutter Apron
- Fascia Rot
- Decay in the wood fascia board behind a gutter, usually caused by water getting behind the gutter: a missing drip edge or gutter apron, overflowing gutters, or leaking seams. Rotten fascia will not hold gutter hangers, so it has to be replaced before new gutters go up.
- See also: Fascia, Gutter Apron, Roof leaks that are really gutter problems
- Felt Underlayment
- Also called: Tar paper, #15 felt, #30 felt
- Traditional underlayment made of paper or fiberglass saturated with asphalt, sold in lighter (#15) and heavier (#30) weights. It is still code-compliant, but most roofers now use synthetic underlayment, which is lighter, stronger and less prone to wrinkling.
- See also: Synthetic Underlayment, Underlayment
- Field
- The main, open area of a roof slope, as opposed to edges, ridges, valleys and penetrations. Hail and wear are often judged on the field.
- See also: Test Square
- Final Inspection
- The building department's inspection after the roof is complete to close the permit. Ask your roofer for proof it passed; an open permit can become a problem when you sell.
- See also: Building Permit, Roofs when buying or selling a home
- Fishmouth
- An open wrinkle or gap at the edge of a membrane seam or lap, shaped like an open mouth. Water and wind get into it, so it is a common repair item on older low-slope roofs.
- See also: Seam, Flat roof repair vs. replacement
- Flashing
- Thin metal or membrane pieces that seal the joints where the roof meets something else: walls, chimneys, skylights, vents, valleys and edges. Most roof leaks are flashing failures rather than failures in the open field of shingles.
- See also: Step Flashing, Counterflashing, Chimney flashing, Roof repair
- Flat Roof
- The everyday name for a low-slope roof. Almost no roof is truly flat: a properly designed one has a slight slope, typically at least 1/4 inch per foot, to move water to drains or edges.
- See also: Low-Slope Roof, Commercial roofing guide, Flat roof repair vs. replacement
- Fleece-Back Membrane
- A single-ply membrane (TPO, PVC or EPDM) with a felt-like fleece layer bonded to the back. The fleece improves adhesion and lets the membrane go over rougher substrates, which is common on recover projects.
- See also: Fully Adhered, TPO
- FM Approval
- Also called: FM rating
- Testing and approval of commercial roof assemblies by FM Approvals, part of the insurer FM Global. A rating like 1-90 means the assembly met Class 1 fire requirements and resisted 90 pounds per square foot of wind uplift. Some commercial insurers require FM-approved assemblies.
- See also: Uplift, Commercial roofing
- FORTIFIED Roof
- A voluntary construction standard from the Insurance Institute for Business & Home Safety (IBHS) for roofs built to resist high wind and wind-driven rain, including a sealed roof deck and stronger fastening and edge details, with a third-party evaluator checking the work and issuing a certificate. Some insurers give a discount for it, and the coastal SC Safe Home grant pays the most for it.
- See also: Wind Mitigation Discount, SC Safe Home
- Freeze-Thaw Cycle
- One swing of temperature below and back above freezing. Columbia sees far fewer of them than northern states, but winter nights below freezing still happen most years, and each cycle lets water in cracks freeze, expand and pry them wider. In the Midlands heat, sun and humidity do more damage to a roof than freezing does.
- See also: Thermal Cracking, How long roofs last in Columbia
- Fully Adhered
- A low-slope membrane glued down across its whole surface to the insulation or cover board below, rather than fastened only at seams or held with ballast. It resists wind flutter and is quieter, at a higher installed cost.
- See also: Mechanically Attached, Ballast
- Gable
- The triangular wall section at the end of a pitched roof, between the two sloping edges. A gable roof has two slopes that meet at a ridge.
- See also: Rake, Hip Roof, Gable Vent
- Gable Vent
- A louvered vent in the gable wall near the peak. It can work as exhaust on simple attics, but mixing gable vents with a ridge vent can short-circuit the airflow so the ridge pulls from the gable instead of the soffits.
- See also: Ridge Vent, Ventilation, Roof ventilation guide
- Galvalume
- Steel coated with an aluminum-zinc alloy for corrosion resistance, widely used for metal roof panels. Galvanized steel uses a zinc-only coating. Both are usually painted for color and extra protection.
- See also: Metal roofing, Standing Seam
- Gambrel Roof
- A barn-style roof with two slopes on each side: a shallow upper slope and a steep lower one. The steep lower slopes and the transition between them need careful flashing and fastening.
- See also: Mansard Roof
- Gloeocapsa Magma
- The cyanobacteria (blue-green algae) behind most black roof streaks in the Southeast. It spreads by airborne spores, feeds on the limestone filler in asphalt shingles, and thrives in warm, humid, shaded conditions. The dark color is a protective coating it produces against UV.
- See also: Algae Streaks, Soft Washing
- Granule Loss
- Shingles shedding their protective granules, showing as bald or dark patches and granules piling in the gutters and at downspouts. It comes from age, hail, foot traffic or manufacturing issues. Once the asphalt is exposed to sun, it ages quickly.
- See also: Common roofing problems, Hail Bruise, How long roofs last in Columbia
- Granules
- The ceramic-coated crushed rock embedded in the top of asphalt shingles. They protect the asphalt from UV light, add color and add fire resistance. Some granules come loose on a new roof, which is normal.
- See also: Granule Loss, Common roofing problems
- Gutter Apron
- A flashing strip at the eaves that tucks under the shingles and extends down into the gutter so water cannot run behind it onto the fascia. It overlaps with drip edge in purpose, and many roofers install one or the other at the eaves depending on the gutter setup.
- See also: Drip Edge, Gutter installation guide
- Gutter Gauge
- Also called: Coil thickness
- The thickness of the metal a gutter is formed from. For aluminum it is usually given in thousandths of an inch; .027 is common residential stock and .032 is heavier and more resistant to denting and sagging. Ask which one a quote includes.
- See also: Seamless Gutter, Gutter materials guide
- Gutter Guard
- A screen, mesh, or solid cover over a gutter meant to keep leaves and pine needles out. Guards cut down on cleaning but do not end it: fine debris, pollen and shingle granules still get through, and some guards need their tops brushed off. Install them so they do not lift or void the warranty on the first course of shingles.
- See also: Gutter guards guide, Pine Needles, Gutter maintenance guide
- Gutter Hanger
- Also called: Hidden hanger
- The bracket that holds a gutter to the fascia. Hidden hangers screw through the gutter into the fascia board and are the modern standard; older spike-and-ferrule systems work loose over time. Hangers are commonly spaced about every 2 feet, and closer under valleys and in heavy-debris areas.
- See also: Fascia, How short fasteners make gutters sag
- Gutter Outlet
- Also called: Drop, outlet tube
- The opening in the bottom of a gutter where the downspout connects. Too few or too-small outlets make a gutter overflow even when the gutter itself is big enough, which is why downspout count matters as much as gutter size.
- See also: Downspout, Roofing calculators
- Gutter Pitch
- Also called: Gutter slope, fall
- The slight slope a gutter is hung with so water runs to the outlet instead of standing. It is small, commonly around 1/4 inch per 10 feet, and too much looks crooked on the house. Standing water in a gutter after rain usually means the pitch is off or a hanger has let go.
- See also: Gutter Hanger, Downspout
- Haag Certification
- Also called: Haag certified inspector
- A credential from Haag, an engineering and training firm, for inspecting roofs for hail and wind damage using consistent, documented methods. Many insurance adjusters train on the same methods, which makes it useful common ground on a claim. It is a training credential, not a license.
- See also: Test Square, Hail Bruise, Hail damage in Columbia
- Hail Bruise
- A soft spot on a shingle where hail cracked the fiberglass mat underneath without necessarily knocking granules off. It feels spongy under light thumb pressure, and over time granules fall away there and the shingle can crack or leak. A bruise, not a scuff, is what distinguishes functional hail damage.
- See also: Hail damage in Columbia, Storm damage repair, Test Square
- Hail Damage
- Damage from hailstones: bruised or cracked shingles, dented metal, split membranes and damaged soft metals like vents and gutters. Functional damage that shortens roof life is what insurers generally cover, not cosmetic dents alone (check your policy).
- See also: Hail Bruise, Hail damage in Columbia, Storm damage repair
- Half-Round Gutter
- A gutter shaped like a pipe cut in half lengthwise, often in copper or on historic homes. It sheds debris well and looks traditional, but carries less water than a K-style gutter of the same width and hangs on exposed brackets.
- See also: K-Style Gutter, Are copper gutters worth it?
- Hand Sealing
- Applying dabs of roofing adhesive under shingle tabs by hand. Manufacturers call for it in certain conditions, such as very steep slopes or cold-weather installs, where the factory sealant strip may not bond on its own before a windstorm.
- See also: Sealant Strip, Blow-Off
- Headlap
- How far each course overlaps the course two rows below it. Headlap is what keeps water that runs through the joints of one course from reaching the deck.
- See also: Exposure, Course
- Heat-Welded Seam
- A seam in a thermoplastic membrane such as TPO or PVC made by melting the two overlapping sheets together with hot air. A properly welded seam becomes one continuous sheet and is checked with a seam probe.
- See also: TPO, PVC Membrane, Thermoset vs. Thermoplastic
- High Nailing
- Driving shingle nails above the manufacturer's nail line. High-nailed shingles miss the overlap of the shingle below, have less holding power and are a leading cause of blow-offs. It is usually a workmanship issue and can affect warranty coverage.
- See also: Nail Line, Blow-Off, Wind damage guide
- Hip
- The sloped external ridge where two roof slopes meet at an outside corner. Hips are capped with hip and ridge shingles or metal trim.
- See also: Hip Roof, Ridge Cap
- Hip Roof
- A roof that slopes down on all four sides to the eaves, with no vertical gable ends. Hip roofs handle wind well but have less room for exhaust vents and produce more cut waste than gables.
- See also: Gable, Waste Factor
- Home Solicitation Sale
- Also called: Door-to-door sale, 3-day right to cancel
- A sale made at your home. Under the federal FTC Cooling-Off Rule, a door-to-door sale of $25 or more made at your home, even one you invited the seller to, generally lets you cancel until midnight of the third business day after signing, and the seller must give you a cancellation form. South Carolina’s own home solicitation law (S.C. Code § 37-2-501) gives the same three days but covers only sales on credit. General information, not legal advice.
- See also: Storm Chaser, Insurance Denial Cancellation, How to hire a roofer in South Carolina
- Hurricane Deductible
- Also called: Named storm deductible, wind/hail deductible
- A separate deductible in many South Carolina homeowners policies for damage from a hurricane, named storm or wind and hail, usually a percentage of the dwelling coverage rather than a flat amount. On a $300,000 policy, a 2 percent deductible is $6,000. South Carolina rules require insurers to show a worked example and a warning on the policy, and a named storm deductible can be triggered only by a storm named by the National Hurricane Center or National Weather Service, not one nicknamed by the news. Read yours before hurricane season.
- See also: Named Storm, Deductible, Hurricane season roof prep
- Ice and Water Shield
- Also called: Self-adhered membrane, peel-and-stick, ice barrier
- A self-adhering rubberized asphalt membrane that sticks directly to the deck and seals around nails. It is used in valleys, around chimneys, skylights and pipes, at low-slope transitions and, in cold climates, along the eaves. The name began as a trademark but is now used generically for any product of this type.
- See also: Ice Barrier, Underlayment, Valley
- Ice Barrier
- The code term for a membrane along the eaves where ice dams are a known problem. The residential code (IRC R905.1.2) requires it only where the local jurisdiction marks a history of ice damming in its code table, so whether it applies to a Midlands home is a question for your building department. When required, it runs from the roof edge to at least 24 inches inside the exterior wall line. Many Columbia roofers use the same membrane in valleys and around penetrations regardless.
- See also: Ice and Water Shield, Ice Dam
- Ice Dam
- A ridge of ice at the roof edge that traps meltwater behind it. Heat escaping from the house melts snow higher on the roof, the water refreezes over the colder eaves, and the pond that builds up can back under shingles. Ice dams are uncommon in the Midlands, where Columbia averages about an inch of snow a year (1991–2020 normal), but they can form after the occasional winter storm on poorly insulated homes.
- See also: Ice Barrier, Attic Air Bypass
- Impact-Resistant Shingle
- A shingle, usually made with a polymer-modified asphalt, that has earned a UL 2218 impact rating, most often Class 4. It tends to hold up better to hail, and some insurers offer a discount. Ask your agent whether yours does before you pay a premium for it.
- See also: Class 4 Impact Rating, Hail damage in Columbia, Roofing materials guide
- Infrared Moisture Survey
- Also called: IR roof scan, thermal scan
- A thermal camera scan of a low-slope roof, usually done after sunset, that finds wet insulation because wet areas hold heat longer than dry ones. Suspect areas are confirmed with core cuts or moisture meters before deciding how much to replace.
- See also: Core Cut, Wet Insulation, Commercial roofing
- Insurance Denial Cancellation
- Also called: Five-day roofing cancellation right
- A South Carolina right (S.C. Code § 40-59-25) for homeowners who sign a roofing contract to be paid from insurance: if the insurer then denies all or part of the claim in writing, you may cancel the contract until midnight of the fifth business day after you receive the denial. The contractor must give you the notice and a cancellation form before you sign, and may not require payment until the window has passed, except for emergency work you acknowledge in writing. General information, not legal advice.
- See also: Deductible Rebating, Home Solicitation Sale, Roof insurance claims guide
- Insurance Fraud
- Knowingly presenting false or inflated information to an insurer, for example an estimate padded to cover your deductible or a claim for damage that happened before the storm. South Carolina treats it seriously for everyone involved, and separately makes it a misdemeanor for a contractor to promise to pay or rebate a deductible. General information, not legal advice.
- See also: Deductible Rebating, Deductible, How to hire a roofer in South Carolina
- Intake Vent
- A vent low on the roof, usually in the soffits or at the roof edge, that lets outside air into the attic. Intake air pushes warm, moist air out the exhaust vents. Most attic ventilation problems are really a shortage of intake.
- See also: Soffit Vent, Exhaust Vent, Baffle
- K-Style Gutter
- Also called: Ogee gutter
- The most common residential gutter shape, with a flat back and bottom and a decorative front that resembles crown molding. For the same width it carries more water than a half-round gutter. Five-inch K-style is standard on many homes; six-inch suits larger or steeper roofs and heavy downpours.
- See also: Half-Round Gutter, Seamless Gutter, Gutter installation guide, Roofing calculators
- Kick-Out Flashing
- Also called: Diverter flashing
- A small angled flashing at the bottom of a roof-to-wall joint that kicks water out into the gutter instead of letting it run down the wall. Missing kick-outs are a common cause of hidden rot in walls below where a roof ends against siding.
- See also: Step Flashing, Chimney flashing
- Laminated Shingle
- Another name for an architectural shingle, referring to the layers glued together.
- See also: Architectural Shingle
- Layover
- Another name for a roof-over or re-cover: new shingles installed over the existing ones without a tear-off.
- See also: Roof-Over
- Lien Waiver
- Also called: Lien release
- A signed document in which a contractor, subcontractor or supplier gives up lien rights for amounts paid. South Carolina has no statutory lien waiver form, so the wording comes from the contractor or your attorney. Before final payment, ask for a release from the roofer and from any supplier or subcontractor that has sent you a notice of furnishing. General information, not legal advice.
- See also: Mechanic’s Lien, Notice of Furnishing, How to hire a roofer in South Carolina
- Line Item
- One priced entry on an estimate, such as tear-off per square, ice barrier per square, drip edge per linear foot, or a pipe boot each. Line items make it possible to compare bids and to see what an insurance estimate did or did not include.
- See also: Estimate, Xactimate, How to read a roofing estimate
- Linear Foot
- Also called: LF
- A straight-line measurement in feet, used for roof edges and trim: drip edge, ridge cap, valleys, step flashing and starter strip are all measured and priced per linear foot rather than per square.
- See also: Square, Aerial Measurement Report
- Liquid-Applied Membrane
- A roof or flashing membrane applied as a liquid, often with reinforcing fabric, that cures into a seamless skin. Useful around odd-shaped penetrations and in restoration systems.
- See also: Roof Coating, Roof coatings
- Low-Slope Roof
- A roof with a slope of 3:12 or less, the typical commercial flat roof and many porch, garage and addition roofs. Shingles are not designed for these slopes; they need a continuous membrane such as TPO, EPDM, PVC or modified bitumen.
- See also: Flat Roof, Steep-Slope Roof, Commercial roofing guide
- Magnet Sweep
- Rolling a magnetic sweeper across the yard and driveway after a roof job to pick up nails. Ask whether it is included, and how often the crew does it.
- See also: Punch List
- Mansard Roof
- A roof with steep, nearly vertical lower slopes on all sides and a shallow or flat upper section. The steep sections are often shingled like walls, and the flat top needs a membrane.
- See also: Gambrel Roof, Low-Slope Roof
- Manufacturer Warranty
- The shingle or membrane maker's warranty covering defects in the material, and, on enhanced system warranties, some installation labor. Coverage usually depends on correct installation, sometimes on using the maker's matching components, and sometimes on registration.
- See also: Workmanship Warranty, Prorated Warranty, Roofing warranties guide
- Mat
- The reinforcing core of an asphalt shingle, today almost always fiberglass (older shingles used organic felt). Hail that fractures the mat creates a bruise even if the surface looks intact.
- See also: Hail Bruise, Asphalt Shingle
- Matching
- The question of whether an insurer must pay to replace undamaged areas so repairs match in color and style, for example when a discontinued shingle cannot be matched. Whether you get it depends on your policy language and state rules, so read the policy and ask your adjuster. General information, not legal advice.
- See also: Supplement, The roof insurance claim process
- Mechanic’s Lien
- Also called: Construction lien, materialman’s lien
- A claim against your property that an unpaid contractor, subcontractor or supplier can file under South Carolina’s mechanic’s lien law (S.C. Code Title 29, Chapter 5). It must be served and filed within 90 days of the last work or materials, and a lawsuit filed within six months. The law caps the total of all liens at what you still owe on the contract, which is why paying ahead of the work is risky and why lien releases before final payment matter. An unlicensed residential contractor cannot file one at all. General information, not legal advice.
- See also: Lien Waiver, Notice of Furnishing, How to hire a roofer in South Carolina
- Mechanically Attached
- A low-slope membrane held down with screws and plates along the seams, which are then covered by the next sheet. It is fast and economical, and fastener spacing is engineered to the wind zone and building height.
- See also: Fully Adhered, Ballast, TPO
- Metal Roofing
- Steel, aluminum, copper or zinc roofing in panel or shingle form. Common residential types are standing seam, exposed-fastener panels and stamped or stone-coated metal shingles. In the Midlands, metal’s main draws are wind resistance, a long service life and reflecting summer heat; its main cost is the higher price up front.
- See also: Metal roofing, Standing Seam, Roof costs by material
- Microburst
- A strong, localized downdraft from a thunderstorm that hits the ground and spreads out, producing straight-line winds that can rival a weak tornado. Microbursts are a common source of summer wind damage in the Midlands: lifted and creased shingles, torn-off ridge caps and downed trees on roofs.
- See also: Straight-Line Wind, Tornadoes and microbursts in the Midlands, Wind damage guide
- Mitigation
- Also called: Duty to mitigate
- The policyholder's obligation, found in most homeowners policies, to take reasonable steps to prevent further damage after a loss, such as tarping a hole. Keep receipts and photos; reasonable emergency repairs are typically part of the claim.
- See also: Tarping, Emergency roof repair, Storm damage roofing guide
- Modified Bitumen
- Also called: Mod-bit, SBS, APP, torch-down
- Asphalt roofing modified with rubbery (SBS) or plastic (APP) polymers and made into rolls, used on low-slope roofs in two or more plies. It is installed by torch, hot asphalt, cold adhesive or self-adhered sheets, and is common on small commercial and residential flat roofs.
- See also: Base Sheet, Cap Sheet, Torch-Down, Commercial roofing guide
- Mortgagee
- Also called: Loss payee
- Your mortgage lender, which is usually named on your homeowners policy. Insurance checks for roof claims are often made out to both you and the lender, and the lender may hold the funds and release them as work is done.
- See also: Roof insurance claims guide, The roof insurance claim process
- Moss
- Green growth that takes hold on shaded, damp roof areas and holds moisture against shingles. On Midlands roofs it usually shows up under tree cover and near lakes. It can lift shingle edges and speed up decay. Remove it gently with a soft wash, and deal with the shade and debris that let it grow.
- See also: Algae Streaks, Soft Washing, Why lake homes grow algae faster
- Nail Line
- The marked strip on a shingle where nails belong, placed so each nail catches both the shingle and the top of the one beneath. Nailing on the line is one of the details manufacturers inspect for warranty.
- See also: High Nailing, Nailing Pattern
- Nail Pop
- A nail that has backed out and pushed up the shingle above it, often from deck movement or a nail that missed the framing or was driven at an angle. Popped nails can wear a hole in the shingle above and let water in.
- See also: Deck, Roof repair guide
- Nailing Pattern
- How many nails go into each shingle and where. Standard patterns use four nails per shingle, while high-wind patterns and steeper slopes call for six. The manufacturer's instructions govern.
- See also: Nail Line, Wind Rating
- Named Storm
- A tropical storm or hurricane given a name by the National Hurricane Center. The term matters for insurance: some South Carolina policies apply a separate, larger deductible to damage from a named storm. By the time most tropical systems reach Columbia they have weakened, but their bands can still bring damaging wind, tornadoes and days of rain.
- See also: Hurricane Deductible, Hurricane season roof prep
- NDL Warranty
- Also called: No-dollar-limit warranty
- A commercial roof warranty from the manufacturer that covers repair of leaks caused by materials or workmanship with no cap on the dollar amount, for a set term. It normally requires an approved installer, a manufacturer inspection at completion and routine maintenance.
- See also: Roofing warranties guide, Commercial roofing
- Net Free Area (NFA)
- Also called: NFA
- The actual open area a vent lets air through, after subtracting screens and louvers, listed by the vent maker in square inches. Attic ventilation is sized by net free area: the residential code's baseline is 1 square foot of NFA per 150 square feet of attic floor, which may drop to 1 per 300 when specific conditions are met.
- See also: Ventilation, Roof ventilation guide, Roofing calculators
- Non-Recoverable Depreciation
- Depreciation an insurer subtracts and will not pay back, even after the work is done. It applies on actual cash value coverage and to some items on otherwise replacement cost policies.
- See also: Recoverable Depreciation, Actual Cash Value (ACV)
- Notice of Furnishing
- A written notice a subcontractor or supplier on a South Carolina job sends to protect its lien rights. If you receive one, it tells you who else expects to be paid out of your job, and that name should get paid and give you a lien release before you make the final payment. General information, not legal advice.
- See also: Mechanic’s Lien, Notice of Project Commencement, Lien Waiver
- Notice of Project Commencement
- An optional notice a South Carolina contractor may file within 15 days of starting work. When it is filed, lower-tier subcontractors and suppliers generally have to send notice of what they are furnishing to keep full lien rights, which gives the owner a clearer picture of who is on the job. General information, not legal advice.
- See also: Mechanic’s Lien, Notice of Furnishing
- NRCA
- The National Roofing Contractors Association, a US trade association that publishes widely used technical guidance, including The NRCA Roofing Manual.
- Off-Ridge Vent
- A short, slotted exhaust vent installed near but below the ridge, used where a continuous ridge vent will not fit, such as on short ridges or hip roofs.
- See also: Ridge Vent, Box Vent
- Open Valley
- A valley lined with metal (or a membrane) that stays exposed, with shingles on both sides cut back from the center. Open metal valleys handle heavy water flow and debris well.
- See also: Valley, Closed-Cut Valley
- Ordinance or Law Coverage
- Also called: Code upgrade coverage
- Insurance coverage for the extra cost of meeting current building codes when damaged property is repaired, for example drip edge or proper ventilation the old roof never had. Many policies include a limited amount, and some require an endorsement. Check your declarations page before a storm, not after.
- See also: South Carolina Residential Code, Roof insurance claims guide
- OSB
- Also called: Oriented strand board
- A structural panel made of wood strands pressed and glued in layers, the most common roof sheathing on newer homes. It performs well when kept dry but swells at the edges and loses strength when it stays wet.
- See also: Deck, Plank Decking
- Overhang
- The part of the roof that extends past the exterior walls at eaves and rakes. Deep overhangs keep water off walls but push the eave further from the warm wall line, which affects how much ice barrier the code requires.
- See also: Ice Barrier, Soffit
- Overhead and Profit (O&P)
- Also called: O&P, 10 and 10
- A charge on an estimate for a contractor's business overhead and profit, often shown as 10 percent plus 10 percent on insurance estimates. Insurers generally include it when a general contractor is reasonably needed to coordinate several trades, but it is not automatic on every claim.
- See also: Xactimate, Supplement, How to read a roofing estimate
- Parapet
- A low wall that extends above the roof line at the edge of a flat roof. Parapets need base flashing, counterflashing and coping, and they can trap water and snow, so drainage has to go through scuppers or drains.
- See also: Coping, Scupper, Base Flashing
- Penetration
- Anything that pokes through the roof: plumbing vents, exhaust fans, chimneys, skylights, satellite mounts, solar standoffs. Each one needs its own flashing and is a potential leak point.
- See also: Pipe Boot, Pitch Pan, Roof repair guide
- Pine Needles
- A constant in Midlands gutters and valleys. Needles mat together, hold moisture against shingles, and slip through many screen-type gutter guards. Valleys under pines need regular clearing, and guards should be chosen with needles, not just leaves, in mind.
- See also: Gutter Guard, Valley, Gutter guards guide
- Pipe Boot
- Also called: Plumbing vent flashing, vent boot
- A flashing that seals around a plumbing vent pipe, usually a metal or plastic base with a rubber collar. The rubber collars crack from sunlight years before the shingles wear out, making them one of the most common residential leak sources.
- See also: Penetration, Roof repair guide
- Pitch
- Also called: Roof pitch, slope
- How steep a roof is, stated as inches of rise per 12 inches of horizontal run, such as 4/12 or 8/12. Strictly speaking, pitch is rise over the full span and slope is rise over run, but roofers use the terms interchangeably.
- See also: Rise and Run, Slope Factor, Roofing calculators
- Pitch Pan
- Also called: Pitch pocket
- A metal collar around an oddly shaped penetration on a flat roof, such as a steel support, filled with sealant. It needs periodic topping off as the filler shrinks. Pre-formed boots are a longer-lasting option where they fit.
- See also: Penetration, Flat roof repair vs. replacement
- Plank Decking
- Also called: Board sheathing, skip sheathing
- Solid wood boards used as roof deck on many older homes. When the gaps between boards are too wide for shingle nails to hold, the deck is typically overlaid with plywood or OSB during a replacement.
- See also: Deck, OSB
- Polyiso
- Also called: Polyisocyanurate, ISO board
- The most common rigid foam insulation board on commercial low-slope roofs, with foil or fiberglass facers. It offers high insulating value per inch, although that value drops somewhat in very cold weather.
- See also: Tapered Insulation, Cover Board, R-Value
- Ponding Water
- Water that remains on a low-slope roof long after rain; the industry commonly treats water still standing 48 hours after a storm as ponding. It points to poor slope or clogged drains, adds weight and shortens membrane and coating life.
- See also: Tapered Insulation, Cricket, Flat roof repair vs. replacement
- Power Vent
- Also called: Powered attic ventilator, attic fan
- An electric or solar fan that pulls air out of the attic. If there is not enough intake, it can pull conditioned air and moisture up from the house, and it should not be combined with a ridge vent on the same attic.
- See also: Ridge Vent, Intake Vent, Roof ventilation guide
- Proof of Loss
- A sworn form some insurers require that states the amount you are claiming. Policies set deadlines for it, so read yours and ask the insurer for the form in writing if they want one.
- See also: Date of Loss, The roof insurance claim process
- Prorated Warranty
- A warranty whose coverage shrinks over time, so a claim in year 18 pays a fraction of what it would in year 2. Most manufacturer shingle warranties have a non-prorated early period, then prorate. Read what the period covers: material only, or labor too.
- See also: Manufacturer Warranty, Roofing warranties guide
- Public Adjuster
- An adjuster you hire, licensed by the South Carolina Department of Insurance, to prepare and negotiate your insurance claim. Under a law that took effect May 19, 2026, a public adjuster’s fee is capped at 10 percent of the settlement and you can cancel the contract within five business days. A roofing contractor is not a public adjuster and may not negotiate your roof claim for you. General information, not legal advice.
- See also: Adjuster, SC Department of Insurance, Roof insurance claims guide
- Punch List
- The list of small items still to finish or correct before a job is complete, such as a missed nail, a dented gutter or trim touch-up. Walk the property with the roofer and agree on the list before the final payment.
- See also: Final Inspection, Lien Waiver
- PVC Membrane
- A thermoplastic single-ply membrane made from polyvinyl chloride, heat welded at the seams. It resists grease and many chemicals, making it a common choice for restaurants and roofs with kitchen exhaust.
- See also: TPO, Heat-Welded Seam, Commercial roofing guide
- R-Value
- A measure of how well insulation resists heat flow; higher is better. On low-slope roofs the insulation is above the deck, so a reroof is often when insulation is upgraded to meet the current energy code.
- See also: Polyiso, Tapered Insulation
- Radiant Barrier
- A reflective foil layer, usually laminated to roof sheathing or stapled to rafters, that reduces the heat radiating from a hot roof deck into the attic. It helps most in hot, sunny climates like the Midlands, but it does not replace insulation or ventilation, and it must face an air space to work.
- See also: Cool Roof, Ventilation, Roof ventilation guide
- Rafter
- One of the sloped framing members that support the roof deck. Many newer homes use factory-built trusses instead of site-framed rafters.
- See also: Truss, Collar Tie
- Rake
- Also called: Rake edge
- The sloped edge of a roof at a gable end, running from eave to ridge. Rakes get drip edge and are high wind-uplift zones.
- See also: Gable, Drip Edge, Eave
- Recover Board
- A thin board installed over an existing low-slope roof before a new membrane goes on in a recover project, to give a clean, flat, compatible surface. Recovering is only appropriate when the existing insulation is dry and the code layer limits allow it.
- See also: Core Cut, Roof-Over
- Recoverable Depreciation
- Depreciation an insurer holds back at first on a replacement cost policy and pays after you complete the work and send proof, such as a final invoice. Policies often set a time limit for claiming it, so ask your adjuster what the deadline is.
- See also: Replacement Cost Value (RCV), Depreciation, Roof insurance claims guide
- Reglet
- A groove cut into masonry, or a metal receiver set into a wall, that holds the top edge of counterflashing so water cannot run behind it.
- See also: Counterflashing, Termination Bar
- Reinspection
- A second visit by the adjuster or a different adjuster, often requested when the roofer's findings differ from the first inspection. Being present with your own documentation, photos and test squares helps.
- See also: Adjuster, Supplement
- Release Tape
- The thin plastic strip on the back of each shingle that keeps bundled shingles from sticking to each other's sealant. It does not need to be removed during installation.
- See also: Sealant Strip
- Replacement Cost Value (RCV)
- Also called: RCV
- The cost to replace damaged property with new material of like kind and quality at today's prices, without subtracting depreciation. On a typical RCV policy the insurer pays the ACV amount first, then the held-back depreciation after the work is done.
- See also: Actual Cash Value (ACV), Recoverable Depreciation, Roof insurance claims guide
- Residential Builder License
- A South Carolina license from the Residential Builders Commission, earned by exam, for residential construction jobs over $5,000. A licensed residential builder may also do roofing without a separate specialty registration, so either a licensed builder or a registered roofer can properly replace a roof. Verify either one on the LLR license lookup. General information, not legal advice.
- See also: Residential Specialty Contractor, Residential Builders Commission, How to hire a roofer in South Carolina
- Residential Builders Commission
- Also called: RBC
- The South Carolina board, part of the Department of Labor, Licensing and Regulation (LLR), that licenses residential builders, registers residential specialty contractors such as roofers, and licenses home inspectors. It also takes written, sworn complaints against them. Its license lookup is the fastest way to check a roofer.
- See also: Residential Specialty Contractor, SC LLR, How to hire a roofer in South Carolina
- Residential Property Condition Disclosure
- Also called: Seller’s disclosure
- The form most South Carolina home sellers must give buyers before the contract is signed (S.C. Code § 27-50-40). Its roof question asks for the approximate year the current roof was installed and any known leaks, repairs or modifications with dates. "No representation" may not be used just to avoid answering, and a seller who later learns the roof is leaking must correct the form. General information, not legal advice.
- See also: Roofs when buying or selling a home
- Residential Specialty Contractor
- Also called: Specialty registrant, roofer registration
- South Carolina’s category for trades such as roofing. A roofer working directly for a homeowner on a job over $500 must be registered with the Residential Builders Commission (the threshold was $200 before May 2022). Registration requires a credit report, references and a year of experience, but no exam, and a $5,000 bond is required only for jobs over $5,000. The registration belongs to the individual, not the company. General information, not legal advice.
- See also: Residential Builders Commission, Residential Builder License, How to hire a roofer in South Carolina
- Restoration
- Also called: Roof restoration, recoat
- Extending the life of an aging but sound low-slope roof by cleaning, repairing and applying a coating system instead of replacing it. It works only when the roof and insulation are mostly dry, which is why a moisture survey comes first.
- See also: Roof Coating, Infrared Moisture Survey, Roof coatings
- Retainage
- A percentage of each payment held back until the job is complete, common on commercial projects, to ensure punch list items and closeout paperwork get done.
- See also: Punch List, Commercial roofing
- Ridge Cap
- Also called: Hip and ridge shingles
- Special shingles or trim that cover the ridge and hips. Using pre-made ridge cap rather than shingles cut from three-tabs is what most manufacturers specify for warranty coverage and wind performance.
- See also: Ridge, Hip
- Ridge Vent
- A continuous exhaust vent along the ridge, with a slot cut in the deck below and a low-profile cover shingled over. Paired with soffit intake, it gives even airflow across the attic.
- See also: Soffit Vent, Ventilation, Roof ventilation guide
- Rise and Run
- The two measurements that define slope: rise is the vertical change and run is the horizontal distance. A roof that rises 6 inches over a 12-inch run is a 6/12 roof.
- See also: Pitch, Slope Factor, Roofing calculators
- Roll Roofing
- Also called: Mineral-surfaced roll roofing
- Asphalt roofing in rolls with a granule surface, used on low-slope sheds, porches and outbuildings. It is inexpensive and short-lived compared with shingles or a real low-slope membrane.
- See also: Low-Slope Roof, Modified Bitumen
- Roof Cement
- Also called: Flashing cement, plastic cement
- A thick asphalt-based mastic used to seal small details and set flashing. It is a supplement to proper flashing, not a substitute. A roof held together with cement usually means flashing that should have been replaced.
- See also: Flashing, Roof repair
- Roof Coating
- A fluid-applied layer (acrylic, silicone, urethane or asphalt-based) that renews the surface of an existing low-slope roof and can add reflectivity. Coatings do not fix wet insulation or failing structure, and they must be compatible with the membrane underneath.
- See also: Restoration, Silicone Roof Coating, Roof coatings
- Roof Drain
- A drain set into a low-slope roof that carries water down through the building to storm lines. Drains need clear strainer baskets; overflow drains or scuppers are a backup if the main drains clog.
- See also: Scupper, Ponding Water, Flat roof repair vs. replacement
- Roof Jack
- Also called: Toe board bracket, roof bracket
- A metal bracket nailed to the roof that holds a board crews can stand on. Roof jacks are part of the fall protection and staging on steeper roofs.
- See also: Steep Charge
- Roof Plane
- Also called: Facet
- One flat, continuous surface of a roof. A simple gable has two planes; a cut-up roof may have fifteen or more. Each plane is measured for area and pitch separately.
- See also: Aerial Measurement Report, Waste Factor
- Roof Surface Payment Schedule
- A policy provision or endorsement that pays for roof damage on a schedule based on the roof's age and material, rather than full replacement cost. It can sharply reduce what an older roof claim pays. Look for it on your declarations page before a storm.
- See also: Actual Cash Value (ACV), The roof insurance claim process
- Roof-Over
- Also called: Re-cover, layover, shingle-over
- Installing a new roof over the existing one without tearing off. The residential code (IRC R908.3.1.1) does not allow it when there are already two or more layers, when the existing roof or deck is water-soaked or deteriorated, or over wood shake, slate, clay, cement or asbestos-cement tile. Even where legal, it hides deck problems and can limit warranty options.
- See also: Tear-Off, Roof-over vs. tear-off, Repair or replace?
- Rot
- Decay of wood decking, fascia or framing caused by fungi that need sustained moisture. Rot is a symptom; the cause is usually a leak, poor ventilation or condensation that has to be fixed along with the wood.
- See also: Deck, Roof repair guide, Rotten roof decking
- Rubber Roof
- The everyday name for EPDM, and sometimes loosely for any single-ply membrane.
- See also: EPDM
- SC Department of Insurance
- Also called: SCDOI
- The state regulator of insurance companies, agents and adjusters, including public adjusters. If you believe your insurer is mishandling a claim, you can file a complaint with it, and its consumer guides explain claims, deductibles and ACV versus replacement cost in plain language.
- See also: Public Adjuster, Roof insurance claims guide
- SC LLR
- Also called: South Carolina Department of Labor, Licensing and Regulation
- The state agency that houses the licensing boards for contractors, including the Residential Builders Commission (homes) and the Contractor’s Licensing Board (commercial). Its online license lookup at verify.llronline.com shows whether a person or company is licensed or registered, in what classification, and whether there is disciplinary history.
- See also: Residential Builders Commission, Contractor’s Licensing Board
- SC Safe Home
- A South Carolina Department of Insurance grant program that helps homeowners pay for wind-resistance retrofits such as roof deck attachment, secondary water barriers and roof-to-wall connections. As of September 2026 it awards grants only in coastal-area counties, not Richland or Lexington, and was not accepting applications. Grant approval has to come before the work starts.
- See also: FORTIFIED Roof, Wind Mitigation Discount
- Scope of Work
- Also called: Scope
- The written description of exactly what will be done: what is removed, what is installed, and which details (flashing, ventilation, decking, cleanup) are included. In insurance, the scope of loss is the adjuster's list of what was damaged and will be paid.
- See also: Estimate, Line Item, How to read a roofing estimate
- Scupper
- An opening through a parapet wall that lets water drain off a flat roof, usually into a collector box and downspout. Overflow scuppers set higher on the wall act as a backup if the main drains clog.
- See also: Parapet, Roof Drain
- Sealant Strip
- Also called: Self-seal strip
- A line of heat-activated adhesive on each shingle that bonds it to the course below once the sun warms it. In the Midlands most roofs seal within days. Shingles installed during a cold stretch may take longer to bond, which is why some installs call for hand sealing, and why a storm soon after a winter install can lift unsealed tabs.
- See also: Hand Sealing, Blow-Off, Wind damage guide
- Seam
- The joint where two sheets of membrane or metal overlap. On single-ply roofs seams are heat welded or taped, and seam failure is one of the most common commercial leak sources.
- See also: Heat-Welded Seam, Fishmouth
- Seamless Gutter
- A gutter roll-formed on site from a coil of aluminum (or steel or copper) into one continuous length for each run, so there are no joints except at corners and outlets. Fewer seams mean fewer places to leak.
- See also: K-Style Gutter, Seamless gutters guide
- Shake
- A wood roofing unit split from a block, usually cedar, so it has a rough, textured face and is thicker than a sawn shingle. Cedar shingles, by contrast, are sawn smooth on both sides.
- See also: Roofing materials guide, Wood Shingle
- Shed Roof
- A single-plane roof sloping in one direction, common on additions, porches and modern designs. Low-pitch shed roofs often need a membrane rather than shingles.
- See also: Low-Slope Roof, Pitch
- Shingle
- An individual overlapping roof unit, made of asphalt, wood, slate, metal, or composite. Shingle roofs shed water rather than being waterproof, so they depend on slope and overlap.
- See also: Asphalt Shingle, Water-Shedding Roof
- Silicone Roof Coating
- A fluid-applied coating for low-slope roofs made from silicone. It holds up well to standing water and UV and is often applied in one thick coat. Future coats generally have to be silicone as well, because most other materials will not stick to it.
- See also: Roof coatings, Acrylic Roof Coating, Roof coatings
- Skylight
- A window in the roof, either curb-mounted or deck-mounted. Skylights usually need their own flashing kit and are a frequent leak source as seals and flashing age. Replacing an older skylight during a reroof is often the practical choice.
- See also: Skylight leaks, Curb
- Slate
- Natural stone split into thin roofing tiles. A good slate roof can last many decades, but it is heavy, needs a skilled installer, and should not be walked on carelessly. Repairs use slate hooks or copper nails and matching stone.
- See also: Roofing materials guide, How long roofs last in Columbia
- Slope Factor
- Also called: Pitch multiplier
- The number you multiply a roof's flat footprint by to get the actual sloped area. For example, about 1.054 for a 4/12, 1.118 for a 6/12, 1.202 for an 8/12 and 1.414 for a 12/12.
- See also: Pitch, Square, Roofing calculators
- Snow Load
- The weight of snow a roof is designed to carry, set by the building code from ground snow load maps. Ground snow loads in the Midlands are low, so snow is rarely a structural concern here. Ice from a winter storm is the bigger risk, mostly because of the tree limbs it brings down.
- See also: Tree and storm debris damage
- Soffit
- The underside of the roof overhang, between the fascia and the house wall. Vented soffits are the main intake for attic ventilation.
- See also: Fascia, Soffit Vent
- Soffit Vent
- A vent in the soffit that lets outside air into the attic. Continuous or individual soffit vents only work if insulation is not blocking them from above.
- See also: Baffle, Intake Vent, Roof ventilation guide
- Soft Washing
- Also called: Soft wash, low-pressure roof cleaning
- Cleaning a roof with a low-pressure spray of a cleaning solution that kills algae, moss and lichen, then letting rain rinse the dead growth away over the following weeks. It is the method shingle manufacturers point to for removing algae streaks. High-pressure washing blasts granules off shingles and can void a warranty.
- See also: Algae Streaks, Gloeocapsa Magma, Roof soft washing
- Solar Attic Fan
- A roof- or gable-mounted exhaust fan powered by its own small solar panel. Like any powered attic fan, it can pull conditioned air out of the house or fight a ridge vent if intake is short, so it should be sized with the rest of the ventilation system, not added on its own.
- See also: Power Vent, Intake Vent, Roof ventilation guide
- Solar Reflectance
- Also called: Reflectivity, SRI
- The fraction of sunlight a roof surface reflects. Solar Reflectance Index (SRI) combines reflectance with how well the surface sheds heat. White membranes and coatings score high; dark shingles score low.
- See also: Cool Roof, Energy-efficient roofing
- South Carolina Residential Code
- Also called: SC Residential Code, IRC
- The building code for one- and two-family homes in South Carolina: the 2021 International Residential Code with South Carolina modifications, in force statewide since January 1, 2023 and administered by local building departments. The 2024 edition, with its own SC modifications, takes effect January 1, 2027. One SC change that matters for roofs: drip edge is required where the shingle manufacturer requires it. Code section numbers on this site (R905, R908 and so on) refer to the 2021 edition.
- See also: Building Permit, Roof permits in South Carolina
- Splash Block
- A concrete or plastic trough set under a downspout outlet to spread the water and steer it away from the foundation. It is the minimum; an extension or underground drain moves the water farther.
- See also: Downspout Extension, Downspout
- Spray Polyurethane Foam (SPF)
- Also called: SPF, spray foam roof
- A low-slope roof system in which liquid foam is sprayed on, expands into a seamless insulating layer, and is then protected with a coating. It must be recoated periodically to protect the foam from sunlight.
- See also: Roof Coating, Commercial roofing guide
- Square
- The roofing unit of area: 100 square feet of roof surface. A 25-square roof has about 2,500 square feet of surface. Materials and labor are usually priced per square.
- See also: Waste Factor, How size and pitch affect cost, Roofing calculators
- Standing Seam
- A metal roof made of long vertical panels whose edges are joined in raised seams, with concealed clips holding the panels so they can expand and contract. No fasteners are exposed to the weather in the panel field.
- See also: Metal roofing, Exposed-Fastener Metal Roof, Roof costs by material
- Starter Strip
- The first course installed along the eaves and often the rakes, with its sealant positioned so the first row of shingles is glued down at the edge. Without it, the first course is the one wind lifts first.
- See also: Course, Blow-Off
- Steep Charge
- Also called: Steep and high roof charges
- Extra labor charged on steep or tall roofs because crews need safety equipment and work more slowly. Insurance estimating typically adds steep charges starting around 7/12 and high-roof charges for roofs two or more stories up.
- See also: Xactimate, How size and pitch affect cost
- Steep-Slope Roof
- A roof steeper than 3:12, where water-shedding coverings such as shingles, slate, tile and metal panels are used. Asphalt shingles may be installed down to 2:12 with extra underlayment.
- See also: Low-Slope Roof, Pitch
- Step Flashing
- Individual L-shaped metal pieces woven in with each course of shingles where a roof slope runs alongside a wall or chimney. Each piece overlaps the one below like the shingles do. Reusing old, rusted step flashing is a common shortcut to ask about.
- See also: Counterflashing, Kick-Out Flashing, Chimney flashing
- Stone-Coated Steel
- Steel roofing panels shaped like shingles, shakes or tile and coated with granules bonded in acrylic. They combine metal's durability with a traditional look.
- See also: Metal roofing, Metal Roofing
- Storm Chaser
- A contractor who follows hail and wind storms from state to state, canvasses door to door, and leaves town after the work, which can make warranty service hard to get. Out-of-state roofers doing residential work in South Carolina need the same state registration as local ones. Check the LLR license lookup, a local address and a track record before signing.
- See also: How to hire a roofer in South Carolina, Home Solicitation Sale, Deductible Rebating
- Straight-Line Wind
- Thunderstorm wind that blows in one general direction rather than rotating. Damage patterns from straight-line wind fan out the same way across a neighborhood, which helps adjusters tell it apart from a tornado.
- See also: Microburst, Wind Damage
- Substrate
- Whatever surface a roofing material is installed on: the deck, insulation, cover board or an existing roof.
- See also: Deck, Cover Board
- Supplement
- A request to the insurance company to add items or quantities missing from the original estimate, such as code-required items, hidden deck damage or measurement errors. A legitimate supplement is backed by photos, measurements and code references.
- See also: Xactimate, Ordinance or Law Coverage, Roof insurance claims guide
- Synthetic Underlayment
- A woven or spun polymer sheet used as roof underlayment in place of asphalt felt. It is lighter, stronger, more tear-resistant and safer to walk on, and it can stay exposed longer before shingling (per the manufacturer's limits).
- See also: Felt Underlayment, Underlayment, Cap Nail
- Tapered Insulation
- Rigid insulation boards cut with a built-in slope, installed on a flat deck to create drainage toward drains or scuppers. It is the standard fix for ponding on commercial roofs during replacement.
- See also: Cricket, Ponding Water, Polyiso
- Tarping
- Covering a damaged roof temporarily with a tarp secured by battens to keep water out until permanent repairs are made. Tarps are a short-term measure; they degrade in sun and wind.
- See also: Mitigation, Emergency roof repair
- Tear-Off
- Removing the existing roof down to the deck before installing a new one. It lets the crew inspect and replace bad decking, install ice barrier and new flashing, and correct ventilation.
- See also: Roof-Over, Roof-over vs. tear-off, Dry-In
- Termination Bar
- An aluminum bar screwed through a membrane at the top of base flashing to hold it tight to the wall, then sealed. It is usually covered by counterflashing.
- See also: Base Flashing, Counterflashing
- Test Square
- A 10-by-10-foot (one square) area marked on a roof slope where an inspector counts hail hits or wind damage. Insurers compare those counts against their own criteria, which vary by carrier, when deciding repair versus replacement.
- See also: Hail Bruise, Haag Certification, Hail damage in Columbia
- Thermal Cracking
- Also called: Thermal splitting
- Cracks in shingles or low-slope membranes caused by repeated expansion and contraction with temperature swings. In the Midlands the big swing is daily: a dark roof can go from a cool dawn to well over 150°F on a summer afternoon. On shingles it often appears as straight splits; on membranes it shows at seams and flashings.
- See also: UV and heat roof damage, Blistering
- Thermoset vs. Thermoplastic
- Two families of single-ply membranes. Thermosets like EPDM are cured and cannot be re-melted, so seams are taped or glued. Thermoplastics like TPO and PVC soften with heat, so seams can be hot-air welded.
- See also: EPDM, TPO, PVC Membrane
- Three-Tab Shingle
- A flat, single-layer asphalt shingle with two cutouts creating three tabs. Once the standard, three-tab shingles have largely been replaced by architectural shingles, and matching them on repairs can be difficult.
- See also: Architectural Shingle, Asphalt shingle roofing
- Tile
- Clay or concrete roofing tiles. Both are durable and fire resistant but heavy, so the framing must be designed for them, and they can crack when walked on or hit by falling limbs. They are uncommon on Midlands homes.
- See also: Roofing materials guide, Batten
- Torch-Down
- Modified bitumen roofing installed by heating the back of the roll with a propane torch to melt it into place. It needs trained installers and careful fire watch, especially near wood and parapets.
- See also: Modified Bitumen
- TPO
- Thermoplastic polyolefin, a white (or light-colored) single-ply membrane for low-slope roofs with heat-welded seams. It is now one of the most common commercial roof membranes.
- See also: Commercial roofing, EPDM, PVC Membrane
- Transferable Warranty
- A warranty that can pass to the next owner when the house is sold, often only once and sometimes with a registration step and fee within a set time after closing. Ask for the paperwork when buying or selling.
- See also: Roofing warranties guide, Roofs when buying or selling a home
- Tree Overhang
- Branches reaching over a roof. In the Midlands, pines and oaks close to the house shade roofs (feeding algae and moss), drop needles and leaves that clog gutters and valleys, scrape shingles in wind, and fall onto roofs in storms. Keeping limbs trimmed back from the roofline is one of the cheapest forms of roof maintenance.
- See also: Pine Needles, Tree and storm debris damage, Roof maintenance guide
- Truss
- A factory-built triangular framing unit that supports the roof, used on most newer homes instead of individual rafters. Trusses should never be cut or altered without an engineer's approval.
- See also: Rafter, Rotten roof decking
- Underlayment
- The water-resistant layer installed over the deck and under the roof covering, acting as a backup for any water that gets past the shingles. It is felt or synthetic sheet in the field and self-adhered membrane at eaves and valleys.
- See also: Synthetic Underlayment, Ice and Water Shield, Felt Underlayment
- Unit Price
- A fixed price per unit for work that cannot be counted in advance, such as a price per sheet of replaced decking or per linear foot of fascia. Unit prices let you compare how bids handle surprises.
- See also: Allowance, Change Order, How to read a roofing estimate
- Uplift
- Also called: Wind uplift
- The suction force wind creates on a roof, strongest at corners, edges and ridges. Commercial roof assemblies and residential shingles are tested and rated for how much uplift they can resist.
- See also: Wind Rating, FM Approval, Wind damage guide
- Valley
- The internal angle where two roof slopes meet and water collects. Valleys carry more water than anywhere else on the roof, so they get ice barrier underneath and careful detailing.
- See also: Closed-Cut Valley, Open Valley, Woven Valley
- Vapor Retarder
- Also called: Vapor barrier
- A layer that slows the movement of water vapor from the warm, humid side of an assembly into the cold side. In cold climates it goes on the warm-in-winter side, below the insulation, to reduce condensation in the roof.
- See also: Condensation, Attic Air Bypass
- Ventilation
- Also called: Attic ventilation
- Controlled airflow through an attic from low intake vents to high exhaust vents. It removes heat and moisture, helps prevent ice dams, frost and mold, and is a condition of most shingle warranties. Balance matters more than adding more exhaust.
- See also: Intake Vent, Exhaust Vent, Net Free Area (NFA), Roof ventilation guide
- Walkway Pads
- Protective pads or rolls laid on a low-slope roof along the paths service technicians use to reach rooftop equipment, so foot traffic does not wear through the membrane.
- See also: Curb, Commercial roofing guide
- Waste Factor
- Extra material added on top of the measured roof area for cutting and fitting. Simple gable roofs often need around 10 percent; hip roofs and cut-up roofs with many valleys need more.
- See also: Square, Hip Roof, Roofing calculators
- Water-Shedding Roof
- A roof covering that keeps water out by slope and overlap rather than by being watertight, such as shingles, slate, tile and shakes. It is why steep-slope materials fail on low slopes, where water moves slowly and can back up.
- See also: Steep-Slope Roof, Low-Slope Roof
- Wear and Tear Exclusion
- The standard insurance policy exclusion for deterioration from age, weathering, neglect and poor maintenance. Insurers cover sudden accidental damage, such as hail or wind, not a roof that simply wore out.
- See also: Roof insurance claims guide, The roof insurance claim process
- Wet Insulation
- Insulation under a low-slope membrane that has absorbed water from leaks. Wet insulation insulates poorly, adds weight, can rot decking and rust steel decks, and usually has to be cut out and replaced.
- See also: Infrared Moisture Survey, Core Cut
- Wind Damage
- Shingles lifted, creased, torn or blown off by wind. A creased shingle has broken its seal and may lift again even if it lies flat now.
- See also: Blow-Off, Wind damage guide
- Wind Mitigation Discount
- Also called: Windstorm credit
- A premium discount or deductible credit an insurer gives for construction that reduces windstorm losses, such as a sealed roof deck, stronger roof-to-wall connections or a FORTIFIED roof. South Carolina law (S.C. Code § 38-75-755) requires insurers to tell you at issue and every renewal which discounts they offer and what you would have to do to earn them. Ask your agent before a reroof, not after.
- See also: FORTIFIED Roof, SC Safe Home, Storm-resistant roofing guide
- Wind Rating
- A shingle's tested wind resistance. Under ASTM D3161, Class F means tested at 110 mph; under ASTM D7158, Class H corresponds to 150 mph. Ratings assume the shingle is installed and sealed per the manufacturer.
- See also: Class 4 Impact Rating, Nailing Pattern, Wind damage guide
- Wind-Driven Rain
- Rain blown sideways or up-slope by strong wind, common in tropical systems and summer squalls. It finds weaknesses a normal rain never tests: open laps, lifted shingles, gaps at flashing and around vents. A leak that only shows up in storms from one direction is often wind-driven rain.
- See also: Flashing, Storm damage roofing guide
- Wood Shingle
- A sawn wood roofing unit, usually cedar, smoother and thinner than a hand-split shake. Wood roofs need good airflow beneath them to dry out.
- See also: Shake, Roofing materials guide
- Workers' Compensation
- Insurance that covers workers injured on the job. In South Carolina it is required for employers with four or more regular employees, so a small roofing crew may legally have none. If an uninsured worker is hurt on your roof, sorting out who pays can land at your door. Ask for a certificate of insurance showing workers’ comp before work starts.
- See also: Certificate of Insurance (COI), How to hire a roofer in South Carolina
- Workmanship Warranty
- The roofing contractor's own guarantee on installation, separate from the manufacturer's material warranty. Its length and terms vary widely, and it is only as good as the company's likelihood of still being around.
- See also: Manufacturer Warranty, Roofing warranties guide, Roofing questions and answers
- Woven Valley
- A valley where shingles from both slopes are laced across the valley in alternating courses. It is used with three-tab shingles and is generally not recommended for thick architectural shingles.
- See also: Valley, Closed-Cut Valley
- Xactimate
- Estimating software, made by Verisk, that most insurers and many contractors use to price claims line by line using regional price lists that are updated regularly. Seeing roof work described in Xactimate line items is normal; the pricing reflects the software's data, not a negotiated contract price.
- See also: Line Item, Supplement, Roof insurance claims guide
- Zinc or Copper Strip
- A strip of zinc or copper installed near the ridge so rain carries trace metal down the roof, discouraging algae and moss. It works best on the area directly below the strip and does little for slopes it does not drain onto.
- See also: Algae Streaks, Moss, Soft Washing
Glossary FAQ
Roofing terms people ask about most
What is a square in roofing?+
What does 6/12 pitch mean?+
The roof rises 6 inches for every 12 inches it runs horizontally, about a 26.6-degree angle. Asphalt shingles can go down to 2/12 with a double layer of underlayment; below that you need a membrane or standing seam metal. Roofs from about 8/12 up are usually priced with a steep charge.
What is the difference between drip edge and gutter apron?+
Both are edge metal. Drip edge pushes water away from the fascia; South Carolina requires it on shingle roofs where the manufacturer does, and the major shingle makers do. Gutter apron extends down into the gutter so water cannot run behind it. At the eaves, roofers use one or the other depending on the gutters; rakes get drip edge.
Do roofs in Columbia need ice and water shield?+
Along the eaves, only if your local building department’s code table designates ice damming as a concern (IRC R905.1.2), so ask yours; Columbia averages about an inch of snow a year. The same self-adhered membrane is widely used here in valleys, around chimneys, skylights and pipes, and on low-slope sections, where water concentrates or can be driven uphill in a storm.
What is the difference between ACV and RCV on a roof claim?+
Replacement cost value (RCV) is the cost to replace the roof new. Actual cash value (ACV) is RCV minus depreciation. On a replacement cost policy the insurer usually pays ACV first and releases the depreciation after the work is complete; some policies pay roofs at ACV even when the rest of the house is RCV. The SC Department of Insurance notes an ACV policy may pay as little as 20 percent on a 20-year-old roof. General information, not legal advice.
What is a hurricane deductible?+
A separate deductible many South Carolina policies apply to damage from a hurricane, named storm or wind and hail, usually a percentage of the dwelling coverage. South Carolina rules require insurers to show how it works with a worked example, and a named storm deductible can only be triggered by a storm named by the National Hurricane Center or National Weather Service. See the full definition.
Can a roofer pay my deductible in South Carolina?+
No. South Carolina law (S.C. Code § 40-59-25) makes it a misdemeanor for a contractor to advertise or promise to pay or rebate any part of an insurance deductible, including through discounts for a yard sign, referral fees, gift cards or credits. It is also grounds for losing their license. General information, not legal advice.
Does a roofer need a license in South Carolina?+
A roofer working directly for a homeowner on a residential job over $500 must be registered with the SC Residential Builders Commission as a residential specialty contractor, or hold a residential builder license. Commercial jobs over $10,000 need a Contractor’s Licensing Board license. Check any contractor on the LLR license lookup. See how to hire a roofer in South Carolina.
What is a hail bruise?+
A soft spot on a shingle where hail fractured the mat underneath. It may not look like much at first, but it feels spongy under light pressure and later loses granules and can crack. Inspectors count bruises in 10-by-10-foot test squares to document hail damage.
What are the black streaks on my roof?+
Almost always algae, usually Gloeocapsa magma, which thrives in the Midlands’ heat and humidity and feeds on the limestone filler in shingles. It is mostly cosmetic at first. A low-pressure soft wash removes it; pressure washing strips granules and can void a warranty.
What size gutters does a house in Columbia need?+
Many homes do fine with 5-inch K-style gutters and 2 x 3 inch downspouts, but large or steep roof sections, valleys that dump into one corner, and heavy pine and oak debris often call for 6-inch gutters and 3 x 4 inch downspouts. The gutter and downspout sizer runs the numbers for Columbia rainfall.
Still have questions?
Want a second set of eyes on your roof?
If a word on your estimate or insurance scope still does not make sense, ask the contractor or adjuster to explain it in writing. Any reputable roofer will. And if you would like another set of eyes on your roof or your paperwork, the team at Cola City Roofing is happy to take a look, whether or not you end up hiring us.
Keep reading
Related roofing resources
Browse all guidesHow to read a roofing estimate
Line by line, what each item on a roofing bid means and what to compare.
How to hire a roofer in South Carolina
Licensing, insurance, contracts, liens and red flags, step by step.
Roofing calculators
Squares, pitch, materials, ventilation and gutter sizing, with the math shown.
Roofs when buying or selling a home
Disclosures, inspections, insurance and what to negotiate.
Roof insurance claims guide
How a South Carolina roof claim works from first call to final check.
305 roofing questions, answered
Shorter answers to the questions homeowners ask most.
Sources
Checked September 24, 2026. Codes and programs change; confirm anything that affects a decision with the agency named.
- International Residential Code 2021, Chapter 8 (R806.2 attic ventilation) and Chapter 9 (R903.2.2 crickets; R905.1.2 ice barriers; R905.2.2 shingle slope; R905.2.8.5 drip edge; R908.3.1.1 recover limits): https://codes.iccsafe.org/content/IRC2021P2
- SC Building Codes Council, codes in effect in South Carolina (2021 IRC with SC modifications, effective January 1, 2023): https://llr.sc.gov/bcc/
- S.C. Code Title 40, Chapter 59 (Residential Builders Commission): § 40-59-20 definitions and thresholds; § 40-59-25 roofing contracts paid from insurance, cancellation, deductible rebating; § 40-59-240 registration and bonds: https://www.scstatehouse.gov/code/t40c059.php
- S.C. Code Title 40, Chapter 11 (Contractor’s Licensing Board), § 40-11-30 license threshold: https://www.scstatehouse.gov/code/t40c011.php
- S.C. Code Title 29, Chapter 5 (mechanics’ liens), §§ 29-5-20, 29-5-23, 29-5-40, 29-5-90, 29-5-120: https://www.scstatehouse.gov/code/t29c005.php
- S.C. Code § 37-2-501 et seq. (home solicitation sales) and FTC Cooling-Off Rule, 16 CFR Part 429: https://www.scstatehouse.gov/code/t37c002.php and https://www.ecfr.gov/current/title-16/chapter-I/subchapter-D/part-429
- Act No. 209 of 2026 (S.196), public adjusters and adjusters, effective May 19, 2026: https://www.scstatehouse.gov/sess126_2025-2026/bills/196.htm
- S.C. Code § 38-75-755 (windstorm discount and deductible disclosures) and § 38-75-485 (SC Safe Home): https://www.scstatehouse.gov/code/t38c075.php; S.C. Code Regs. 69-56 (hurricane, named storm or wind/hail deductibles): https://www.scstatehouse.gov/coderegs/Chapter%2069.pdf
- SC Department of Insurance, Post-Disaster Claims Guide (ACV and RCV): https://doi.sc.gov/DocumentCenter/View/14784/SCDOI-publication-post-disaster-claims-guide; SC Safe Home program: https://doi.sc.gov/605/SC-Safe-Home
- S.C. Code Title 27, Chapter 50 (Residential Property Condition Disclosure Act) and the SC Real Estate Commission disclosure form (updated 6/2025): https://llr.sc.gov/re/recpdf/Property-Condition-Disclosure-Statement-06.2025.pdf
- SC LLR license lookup: https://verify.llronline.com/LicLookup/LookupMain.aspx
- UL 2218 impact resistance of prepared roof coverings; ASTM D3161 and ASTM D7158 wind resistance of asphalt shingles: https://www.ul.com, https://www.astm.org
- National Hurricane Center, Atlantic hurricane season: https://www.nhc.noaa.gov