By The Roofing Brief Team. Last reviewed: October 2026.
Roofing terms are the words a contractor, estimator or insurance adjuster uses on your project, usually heard for the first time mid job.
The 55 entries below span five groups, from structure to insurance and warranty. Our roofing FAQ covers the questions they lead to. IRC section numbers cite the 2018 edition; confirm the one your jurisdiction adopted.
Estimate and insurance words, not roof parts, blindside homeowners: actual cash value, recoverable depreciation, supplement, overhead and profit.
They decide what you pay out of pocket. For the roof parts themselves, see our roofing terminology with pictures.
Roofing terms quick reference: the 12 you hear most
These 12 roofing terms come up in almost every replacement conversation; the table gives each meaning and why it affects your bill.
| Term | What it means | Why it matters to you |
|---|---|---|
| Square | 100 square feet of roof area | Roofs are priced per square, not per shingle |
| Pitch (slope) | Steepness, written as rise over 12 (for example 6:12) | Steeper roofs cost more to install and are harder to walk |
| Tear-off | Removing old roofing down to the deck | Adds labor and disposal cost versus an overlay |
| Decking (sheathing) | The wood surface the roof attaches to | Rotten decking is a common surprise line item |
| Underlayment | The water-resistant layer under the shingles | Code often requires an upgrade in cold climates |
| Flashing | Metal that seals joints and penetrations | A common leak source, so inspectors check it first |
| Drip edge | Metal along the roof edges | IRC R905.2.8.5 requires it at eaves and rakes of shingle roofs |
| Ridge / hip / valley | The top line, the outward angles, the inward channels | Valleys and flashing points drive leak risk |
| ACV | Actual cash value, depreciated payout | The first insurance check, smaller than the total |
| RCV | Replacement cost value, full price to rebuild | What you can recover if you complete the work |
| Deductible | Your share before insurance pays | Subtracted from every claim payout |
| Overlay (re-cover) | New shingles over the old ones | Cheaper up front, but IRC R908.3.1.1 bars a recover over a roof that already has two layers |
If your quote or claim says…, then do this
| If the quote or claim says | Then | Because |
|---|---|---|
| Overlay or re-cover | Ask how many layers are already on the roof | IRC R908.3.1.1 bars a recover over two or more applications |
| Pitch under 4:12 | Confirm double underlayment, or a membrane under 2:12 | IRC R905.2.2 slope rules for asphalt shingles |
| Insurer pays ACV only | Keep the final invoice and request the recoverable depreciation | RCV is paid after the work is complete |
| Adjuster estimate missing decking or code items | File a supplement with photos and line items | Supplements for mid-job discoveries are common |
| Contractor offers an assignment of benefits | Read it before signing; check your state’s limits | It transfers your claim rights |
| Bid with no starter strip or drip edge line | Ask for them in the scope of work | Drip edge is required at eaves and rakes by IRC R905.2.8.5 |
Roof structure and parts terms
Structure terms name the physical pieces of the roof, from frame to edges; see the parts of a roof for the labeled anatomy.
- Ridge. The horizontal line at the top where two roof planes meet, capped with ridge shingles and often fitted with a ridge vent.
- Hip. An external angle where two slopes meet and project outward. Hip roofs slope on all four sides.
- Valley. The internal V-shaped channel where two slopes meet. Open metal valley linings must be at least 24 inches wide under IRC R905.2.8.2.
- Eave. The lower horizontal edge of the roof that overhangs the wall, where gutters attach. Ice dams form here in cold climates.
- Rake. The sloped edge at a gable end, from eave to ridge. It takes drip edge and rake trim, not gutters.
- Fascia. The horizontal board along the eave that the gutters mount to. Wood fascia rots when gutters overflow or drip edge is missing.
- Soffit. The underside panel of the eave overhang. Vented soffit pulls intake air into the attic to balance the ridge vent.
- Decking (sheathing). The plywood or OSB nailed to the rafters. Rotten decking is a common added cost on a tear-off.
- Rafters and trusses. The angled framing members that hold up the decking. Rafters are cut on site, trusses are prefabricated triangles.
- Flashing. Sheet metal at joints, walls, chimneys and penetrations that directs water away; a common leak source, so flashing is inspected first.
- Drip edge. The L-shaped metal along eaves and rakes that carries water into the gutter. IRC R905.2.8.5 requires it, overlapped at least 2 inches.
- Ridge vent. A vent along the ridge that exhausts hot attic air. It works only when paired with soffit intake vents.
Roofing material terms
Material terms name what the roof is made of and the layers beneath it, and they appear on the estimate and the maker’s warranty.
- Asphalt shingle. A fiberglass mat coated in asphalt and topped with mineral granules. It covers most American homes and is cheap to repair.
- 3-tab shingle. A flat, single-layer asphalt shingle with three tabs. It is the cheapest and shortest lived, commonly rated around 25 years.
- Architectural shingle. Also called dimensional or laminate, a multi-layer asphalt shingle that looks thicker and lasts longer, commonly 30 years or more. It is now the default choice on most replacements.
- Granules. The mineral bits on the shingle surface. They block UV; bare spots signal an aging or hail-struck roof.
- Underlayment. The layer between deck and shingles, from felt to lighter, tear-resistant synthetic. IRC R905.1.1 sets the requirements.
- Ice and water shield. A self-adhered waterproof membrane applied at eaves, valleys, and penetrations. The IRC (section R905.1.2) requires an ice barrier in regions with a history of ice dams.
- Modified bitumen. A rolled asphalt membrane reinforced with polymers, used on low-slope roofs. It is installed in torch-down, cold-adhesive, or self-adhered sheets.
- EPDM. A synthetic rubber membrane for flat and low-slope roofs, usually black, valued for a long service life at low cost.
- TPO. A white single-ply thermoplastic membrane that reflects heat, common on commercial flat roofs and some low-slope residential sections.
- Standing seam metal. Vertical metal panels joined by raised seams that hide fasteners. IRC R905.10.2 allows it down to 1/4:12, and a 40-plus year life is typical.
Measurement and estimate terms
Measurement terms turn your roof into numbers on a bid, and estimate terms decide how those numbers add up. The single most important word is square. A roofing square equals 100 square feet, and roofers price nearly everything by it. The Roofing Brief 2026 Roofing Cost Report tracks installed asphalt pricing, which commonly runs a few dollars per square foot depending on region and access.
- Square. A unit equal to 100 square feet of roof area. A 2,000 square foot roof is 20 squares. Material and labor are both quoted per square.
- Pitch. The steepness of the roof, written as vertical rise over 12 inches of horizontal run. A 6:12 pitch rises 6 inches per foot. Higher pitch means higher labor cost.
- Slope. Often used interchangeably with pitch. Anything flatter than roughly 3:12 is treated as low-slope and needs different materials.
- Low-slope. A roof flatter than about 3:12. Asphalt shingles are not allowed under 2:12, and 2:12 to 4:12 needs double underlayment (IRC R905.2.2).
- Course. A single horizontal row of shingles or underlayment. Roofs are installed one course at a time from the eave up.
- Exposure. The visible portion of each shingle after the next course overlaps it, typically about 5 to 6 inches on standard shingles. It controls how many shingles a square needs.
- Line item. A single priced entry such as tear-off or underlayment. Compare line items, not totals, to catch what a low bid omitted.
- Scope of work. The written list of everything the contractor will do. A vague scope is the most common source of change-order disputes.
- Overhead and profit (O&P). A markup, commonly around 10 and 10 (10 percent each), that covers the contractor’s business costs and margin. It appears on both contractor bids and insurance estimates.
Installation and method terms
Method terms describe how the roof goes on. The biggest fork is tear-off versus overlay, which changes both price and lifespan.
- Tear-off. Stripping all existing roofing to the bare deck. It costs more in labor and disposal but lets the crew replace bad decking (IRC R908.3).
- Overlay (re-cover). Installing new shingles over the old layer. IRC R908.3.1.1 bars a recover where the roof already has two or more applications.
- Starter strip. The first shingle course at eave and rake, sealing the edge against wind uplift. Skipping it is a common corner-cut.
- Hip and ridge cap. Thicker shingles bent over hips and ridge to finish and seal them, sold separately from field shingles.
- Pipe boot. The rubber or metal collar sealing a plumbing vent pipe. The rubber gasket cracks over time, a frequent and cheap leak fix.
- Step flashing. Individual bent metal pieces woven into each course where roof meets wall. IRC R905.2.8.3 sets a 4 inch minimum height and width for sidewall flashing.
- Counter flashing. A second flashing set into a chimney or wall, covering the top edge of the base flashing so water cannot run behind the seam.
- Open versus closed valley. An open valley leaves metal exposed in the channel (24 inches wide minimum, per R905.2.8.2); a closed valley runs shingles across it.
- Reroof. A general term for redoing the roof, by either tear-off or overlay. Ask which method a reroof quote assumes.
Insurance and claims terms
Insurance terms decide how much the carrier pays. The core split is ACV versus RCV, with depreciation and your deductible between them.
| Concept | Actual cash value (ACV) | Replacement cost value (RCV) |
|---|---|---|
| What it pays | Depreciated value of the roof today | Full cost to replace with new |
| When you get it | First check, up front | After the work is completed and invoiced |
| Depreciation | Held back | Recoverable once you finish |
| Your net cost | Higher if you stop at ACV | Deductible only, if you recover depreciation |
- Claim. Your formal request for payment of covered roof damage, usually wind, hail or a falling tree. Wear and neglect are not covered.
- Adjuster. The insurer’s representative who inspects the roof and writes the estimate. A public adjuster works for you, not the carrier.
- Actual cash value (ACV). The depreciated value of your roof, replacement cost minus wear. It is the smaller first payment on a replacement-cost policy.
- Replacement cost value (RCV). The full cost to replace the roof with equivalent new material, before depreciation. It is what you can ultimately recover if you complete the repair.
- Recoverable depreciation. The gap between ACV and RCV that the insurer releases after you finish the work and submit the final invoice.
- Deductible. The fixed amount you pay before coverage starts, subtracted from the payout. On many policies it is a percentage of dwelling coverage.
- Supplement. An added request for costs the first estimate missed, such as extra decking or code-required upgrades found mid-job.
- Betterment. The part of an upgrade you pay for when new work improves the property beyond its prior state.
- Xactimate. The estimating software most carriers use to price claims, from Xactware (Verisk). Contractors often write their own Xactimate estimate to match the adjuster line by line.
- Assignment of benefits (AOB). A contract transferring your claim rights to the contractor. Several states have restricted it, so read it carefully.
Warranty terms
Warranty terms split into two promises: the manufacturer covers the shingles, the installer the labor. See manufacturer and workmanship warranties for the full breakdown.
- Manufacturer warranty. Covers defects in the shingle or membrane itself, issued by the maker such as GAF or Owens Corning. It does not cover bad installation.
- Workmanship warranty. Covers installation errors, issued by the contractor who did the work. Length varies widely, from 1 year to lifetime, and is only as good as the company staying in business.
- Prorated. A warranty whose payout shrinks each year as the roof ages. Most basic material warranties are prorated after an initial full-coverage window.
- Non-prorated. Full coverage for a set number of years with no reduction, common in the early period of an enhanced warranty.
- Transferable. A warranty that can pass to the next homeowner, often once and within a time limit. It adds resale value.
- System (enhanced) warranty. An upgraded manufacturer warranty, such as the GAF Golden Pledge, that covers both material and workmanship but requires a certified installer and a full system of matched components.
Frequently asked questions about roofing terms
What does “square” mean in roofing?
A square in roofing equals 100 square feet of roof area. It is the standard unit contractors use to price both materials and labor, so a 2,000 square foot roof is 20 squares. Shingles are sold in bundles, and it typically takes three bundles of architectural shingles to cover one square. Estimates quoted per square let you compare bids on the same basis.
What is the difference between roof pitch and slope?
Pitch and slope both describe how steep a roof is, and in everyday roofing talk they are used interchangeably. Both are written as vertical rise over a 12-inch horizontal run, so a 6:12 roof rises 6 inches per foot. The practical lines are 2:12 and 4:12: asphalt shingles are not allowed under 2:12 and need double underlayment from 2:12 to 4:12 (IRC R905.2.2); flatter roofs use a membrane system.
What is the difference between ACV and RCV on a roof claim?
ACV (actual cash value) is your roof’s depreciated worth and the smaller first check. RCV (replacement cost value) is the full cost to replace it. The difference is recoverable depreciation, released when you send the final invoice.
What does tear-off mean versus overlay?
A tear-off removes all old roofing down to the wood deck, which lets the crew replace rotten decking. An overlay (re-cover) installs new shingles over the existing layer. It costs less up front, but IRC R908.3.1.1 bars it where the roof already has two layers, and it hides deck damage.
What is flashing and why does it matter?
Flashing is sheet metal installed at joints, walls, chimneys, valleys, and pipe penetrations to steer water away from the seams. It is a common leak source, so roofers inspect chimney and wall flashing first.
What does overhead and profit (O&P) mean on an estimate?
Overhead and profit is a markup that covers a contractor’s business costs and margin, commonly quoted as 10 and 10, meaning 10 percent overhead plus 10 percent profit. It appears on both contractor bids and insurance estimates. On complex claims that involve multiple trades, insurers are generally expected to include O&P, so it is worth confirming it is in the payout.