Reference

The roofing glossary

Every trade term you will meet in an estimate, an insurance scope, or a driveway conversation, defined the way a contractor would explain it across the kitchen table. 73 terms and counting.

A

ACV (actual cash value): What your roof is worth today: replacement cost minus depreciation for age and wear. An ACV policy pays only this amount, which on an older roof can be less than half the cost of replacing it. How claims actually work
Adjuster: The insurance company's field representative who inspects damage and writes the claim scope. Not your enemy, not your advocate: a busy professional whose report improves when real damage is documented and pointed out.
Architectural shingle: A laminated, two-layer asphalt shingle with a dimensional look, the standard choice on most homes today. Heavier and more wind-resistant than 3-tab, typically rated 110 to 130 mph. Architectural vs 3-tab

B

Boot (pipe boot): The flashing collar that seals around plumbing vent pipes where they exit the roof. The rubber ones crack from UV in 10 to 15 years and are one of the most common leak sources on otherwise healthy roofs.
Box vent: A static exhaust vent (also called a turtle vent) installed near the ridge, rated around 50 square inches of net free area each. Never mix box vents and ridge vents on the same attic.
Bundle: The package shingles ship in. Standard shingles pack three bundles per square, so a bundle covers about 33 square feet. A 20 square roof with 10 percent waste is 66 bundles on the driveway.

C

Class 4 (UL 2218): The highest impact-resistance rating for shingles, earned by surviving a 2 inch steel ball dropped from 20 feet without cracking. Many carriers discount premiums for it in hail states, sometimes with a cosmetic-damage exclusion attached. Are Class 4 shingles worth it?
Closed valley: A valley where shingles from one plane weave or lay across the valley line instead of exposing metal. Cheaper and common; open metal valleys shed water and debris better on long or steep valleys.
CLUE report: The Comprehensive Loss Underwriting Exchange, a shared claims database carriers check when pricing your policy. Claim activity, including denied and zero-paid claims, can sit on it for up to 7 years.
Counter flashing: The upper flashing layer, typically cut into a chimney or wall mortar joint, that laps over step flashing so water cannot get behind it. Caulk smeared where counter flashing belongs is a red flag.
Cricket: A small peaked diverter built on the high side of a chimney or wide roof penetration to split water around it. Code requires one behind chimneys wider than 30 inches.

D

Date of loss: The specific date the covered storm event damaged your roof. Claims are built on it: carriers verify it against weather data, and policies set deadlines that count from it.
Decking (sheathing): The wood layer (plywood or OSB) fastened to the rafters that everything else attaches to. Rot and delamination are found at tear-off, which is why estimates carry a per-sheet replacement price.
Deductible: Your out-of-pocket share of a claim. Wind and hail deductibles are increasingly a percentage of dwelling coverage: 1 percent on a $400,000 house is $4,000, not $1,000. A contractor offering to absorb it is proposing fraud.
Depreciation: The age-and-wear discount applied to your roof's value in a claim. On replacement cost policies it is recoverable: the carrier holds it back, then releases it once the work is completed and invoiced.
Dormer: A framed structure projecting from the roof, usually with a window. Dormers add valleys, flashing, and cut waste, which is part of why complex roofs cost more per square.
Drip edge: L-shaped metal at eaves and rakes that kicks water off the edge and into the gutter instead of behind the fascia. Code in most jurisdictions, and a classic line lowball bids quietly omit.

E

Eave: The lower horizontal edge of the roof where it overhangs the wall, home to gutters, drip edge, starter strip, and the intake half of your ventilation system.
EPDM: A synthetic rubber membrane for flat and low-slope roofs, usually black, glued or mechanically fastened. Durable and repairable; a standard choice on low-slope additions and porches.
Exposed fastener panel: Metal roofing screwed down through the panel face (screw-down, ag panel, PBR). Cheaper than standing seam, but hundreds of gasketed screws are a maintenance schedule: they back out and the gaskets age.

F

Fascia: The vertical trim board at the eave that gutters attach to. Peeling paint or soft fascia usually means water has been getting past the drip edge or gutter for a while.
Felt underlayment: The traditional asphalt-saturated paper (15 lb or 30 lb) installed between decking and shingles. Still code-legal; synthetic underlayment has largely replaced it for tear strength and walkability.
Flashing: Metal that waterproofs every transition: walls, chimneys, valleys, edges, penetrations. Most roof leaks are flashing failures, not shingle failures, which is why reusing old flashing on a new roof is false economy.

G

Gable: The triangular wall section under a two-plane roof, and the name for that simple roof shape. Gable roofs are the cheapest to build and reroof; the math on this site's calculators assumes you know yours.
Granules: The crushed mineral surface on asphalt shingles that blocks UV and provides fire resistance. Piles of granules in gutters after a storm are evidence; steady thinning over years is age.

H

Hail bruise: A hail strike that displaces granules and fractures the shingle mat underneath. Feels like a bruised apple under your thumb. Bruises may not leak for 1 to 3 years, which is how damage gets missed until the claim window closes. Hail damage signs homeowners miss
High nailing: Nailing shingles above the manufacturer's nail line, missing the course below. It halves the wind resistance and voids warranties, and you cannot see it from the ground. A common finding when new roofs blow off.
Hip: The external angle where two roof planes meet, running from ridge to eave. Hip roofs shed wind well but generate more cut waste, and their ridgelines need hip cap shingles.

I

Ice and water shield: Self-adhering rubberized membrane applied at eaves, valleys, and penetrations that seals around nails. Code requires it at eaves in cold climates; good practice puts it in every valley everywhere.
Ice dam: A ridge of ice at the eave formed when attic heat melts snow that refreezes over the cold overhang, ponding water under the shingles. The cure is insulation and ventilation, not just heat cables.

L

Layover (roof-over): Installing new shingles over the old layer instead of tearing off. Saves money up front, hides the deck, runs hotter, shortens the new roof's life, and makes the eventual tear-off cost more.
Low-slope: Roof pitch at or below about 2/12, where shingles are not allowed and membranes or standing seam take over. Between 2/12 and 4/12, shingles need enhanced underlayment. Pitch calculator

M

Matching (line of sight): The question of whether repaired sections must match the rest of the roof. Some states require carriers to address reasonable uniformity; discontinued shingles often force bigger scopes. Rules vary by state and policy.
Modified bitumen: Asphalt sheet roofing reinforced with polymers, torched or self-adhered in rolls, for flat and low-slope roofs. The granulated surface makes people mistake it for shingle material; it is its own system.
Mortgagee endorsement: Your lender named on the insurance check. Banks endorse claim checks per their own process, sometimes holding funds in escrow and releasing by inspection milestones. Build the timeline into your plans.

N

Nail pop: A nail that has backed out and tented or pierced the shingle above it. Caused by decking movement or short nails, fixed cheaply, and not storm damage no matter what a door knocker says.
NFA (net free area): The actual open airflow area of a vent in square inches, after screens and louvers. Ventilation is sized by adding NFA, not by counting vents. Ventilation calculator

O

O and P (overhead and profit): The general contractor markup (commonly 10 and 10) carriers add to claims complex enough to require coordinating multiple trades. Whether a roof-plus-gutters-plus-interior claim qualifies is a frequent supplement discussion.
Open valley: A valley lined with exposed metal (often painted steel or aluminum) with shingles trimmed back on both sides. Sheds water and debris better than closed valleys and makes future repairs cleaner.
OSB (oriented strand board): Engineered wood decking made of compressed strands, the most common roof deck on homes built since the 1990s. Fine when dry, but edges swell with chronic moisture, which is what deck inspections look for.

P

Pitch: Roof steepness written as rise over run: a 6/12 roof rises 6 inches per 12 inches of run, about 26.6 degrees. Pitch gates material choices, walkability, labor cost, and how much surface a footprint carries. Pitch calculator
Ponding: Water still standing on a flat or low-slope roof 48 hours after rain. It accelerates every failure mode a membrane has and usually signals a slope or drainage design problem.
Public adjuster: A state-licensed professional who represents you (not the carrier) in a claim for a percentage of the settlement, typically on large or disputed losses. Different role from your contractor, who documents and prices the repair.
PVDF (Kynar 500): The premium factory paint system on quality metal roofing, resistant to fade and chalk for decades. The cheaper alternative (SMP) fades faster. On a 50 year panel, the coating is what actually ages.

R

Rake: The sloped edge of a gable roof from eave to ridge. Rake edges get drip edge and often starter strip, and wind works on them first.
RCV (replacement cost value): What it costs to replace your roof at today's prices. RCV policies pay this minus your deductible, releasing recoverable depreciation after completion. Check your declarations page for RCV vs ACV before you ever need it.
Recoverable depreciation: The depreciation a replacement cost policy holds back until the work is done and invoiced. Homeowners who do not know it exists try to build full roofs on the first check, or worse, pocket an ACV payment and lose it.
Ridge: The horizontal peak where roof planes meet, finished with cap shingles and, on most modern roofs, the ridge vent that exhausts the attic.
Ridge cap: Purpose-made or cut shingles that saddle the ridge and hips, about one bundle per 25 lineal feet. Matching cap to the field shingle brand protects the wind warranty.
Ridge vent: A continuous exhaust vent under the ridge cap, around 18 square inches of NFA per lineal foot. It only works when soffit intake feeds it; a ridge vent over blocked soffits pulls weather and conditioned air instead.
Rise: The vertical component of pitch: how many inches the roof climbs per 12 inches of horizontal run. Measure it in the attic with a level and a tape.
Run: The horizontal component of pitch, standardized at 12 inches so pitch reads as rise over 12. Also the half-span a rafter covers from wall to ridge.

S

Scope (of loss): The carrier's line-item description of what the claim covers: quantities, materials, labor operations, and prices. First scopes routinely miss items; correcting them with documentation is the supplement process. Supplements explained
Sealant strip (self-seal): The factory adhesive line on shingles that heat-bonds each course to the next. Broken seals from wind mean shingles lift in the next storm even when they look flat today; adjusters check for it by hand.
Soffit: The underside of the eave overhang, where intake ventilation lives. Painted-shut or insulation-blocked soffit vents are the most common ventilation failure on real houses.
Soft metals: Aluminum vents, flashings, gutters, and AC fins that dent visibly in hail. Adjusters read soft metal damage to confirm hail size and direction, which is why you photograph it before it gets repaired.
Square: The roofing unit of area: 100 square feet. Everything in the trade prices per square. Your roof is your footprint times a pitch factor, in squares. Roof area calculator
Standing seam: Metal roofing with raised interlocking seams and hidden clips, no exposed fasteners in the field. The premium metal system: 40 to 60 year service life, priced two to three times architectural shingles installed.
Starter strip: The first course at eaves (and often rakes) with the adhesive positioned to lock down the field shingles' bottom edge. Cut-up 3-tabs used as starter is an old shortcut that costs wind resistance.
Step flashing: Individual L-shaped metal pieces woven shingle-by-shingle where a roof meets a wall, each course stepping up the slope. The right way to flash a sidewall; a single bent channel smeared with sealant is not.
Supplement: A documented request to add missed or code-required items to an insurance scope after work begins or during review. Normal and legitimate when supported by photos and code citations; abused when invented.
Synthetic underlayment: Woven polymer underlayment that replaced felt on most quality jobs: lighter, far stronger, safer to walk, and stable if weather delays shingles. Covers about 10 squares per roll.

T

Tear-off: Stripping the old roof down to decking before installing the new one. It is how decking problems get found and fixed, and why a second existing layer adds real cost: more labor, more disposal weight.
Test square: A 10 by 10 foot area an adjuster chalks off per slope to count hail hits. A common carrier rule of thumb is 8 or more hits in a test square to qualify a slope, though standards vary by carrier. What adjusters look for
Thermal splitting: Cracks through shingles from temperature cycling and asphalt shrinkage, usually in straight lines across the roof. It is an age and manufacturing story, not storm damage, and carriers know the difference.
Three-tab shingle: The older single-layer asphalt shingle with two slots forming three flat tabs. Cheaper per square, lighter wind ratings (60 to 70 mph), and its tab edges are the first thing to curl and crack after year 10.
TPO: A white, heat-welded single-ply membrane dominating flat commercial roofs and increasingly used on residential low-slope sections. Reflective and clean when installed by crews who actually weld it right.

U

Underlayment: The water-shedding layer between decking and roofing: felt, synthetic, or self-adhering membrane. It is the backup plan for everything above it, and code requires it.

V

Valley: The internal channel where two roof planes drain into each other. Valleys carry more water at higher speed than any other part of the roof, which is why they get membrane and careful detailing.

W

Waste factor: The extra material ordered beyond measured area to cover cuts at hips, valleys, rakes, and starts: 10 percent on simple roofs, 15 percent or more on cut-up ones. Not padding; geometry. Materials calculator
Wind crease: A horizontal fold line across a shingle tab that lifted in wind and bent back. Creased tabs have broken seals and reduced strength; a slope with widespread creasing is wind damage even with nothing missing.
Wind uplift: The suction force wind creates over roof surfaces, strongest at edges, rakes, and corners. It is why edge details, starter strip, and correct nailing matter more than the field, and why ratings are edge-tested.

X

Xactimate: The estimating software most carriers and restoration contractors use to price claims with standardized line items and regional pricing. When your contractor and adjuster argue scope, they are usually arguing Xactimate line items.

Missing a term?

If you hit a word on an estimate or a claim document that is not here, tell us and it gets added. That is how a manual stays a manual.