Roofing contracts, insurance adjusters, and contractors use industry-specific terminology that can leave homeowners nodding along without fully understanding what they're agreeing to. Here are the terms you'll encounter most often — defined clearly, without jargon.
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Materials and Components
Architectural Shingle
Laminated two-layer asphalt shingle; the standard for modern residential roofing. Also called dimensional or laminated shingles. 25–30 year rated life.
3-Tab Shingle
Single-layer asphalt shingle with three uniform cutouts along the bottom edge. Largely obsolete; lower wind resistance and shorter life than architectural.
SBS Modification
Styrene-butadiene-styrene polymer added to asphalt to create a rubber-like flexibility. Required for Class 4 impact resistance; improves cold-climate performance.
Class 4 IR
Highest UL 2218 impact resistance rating. Shingles survive two drops of a 2-inch steel ball from 20 feet without cracking. Earns insurance premium discounts in hail-active states.
Underlayment
Water-resistant layer installed directly on the roof deck beneath shingles. Felt (15 or 30 lb) or synthetic are the two main types. Provides secondary protection if shingles are damaged.
Ice and Water Shield (IWS)
Self-adhering waterproof membrane that bonds to the deck and seals around fasteners. Required at eaves in cold climates; best practice at all valleys.
Flashing
Metal strips (aluminum, galvanized steel, or lead) that seal transitions between the roof surface and vertical surfaces, penetrations, and changes in plane.
Step Flashing
Individual L-shaped metal pieces installed in alternating steps where a roof slope meets a vertical wall. More reliable than continuous flashing cement.
Counter Flashing
Metal that overlaps the top of step flashing, embedded in masonry joints or behind siding. Prevents water from entering behind step flashing at walls and chimneys.
Drip Edge
L-shaped metal strip at roof edges that directs water away from fascia into gutters. Required by most codes; often missing on older roofs.
Ridge Cap
Specially formed shingles installed along the roof peak (ridge) that cover the joint between both slopes. High-wind area; common first failure point in storms.
Starter Strip
Pre-adhesived shingle installed at eaves before the first full course. Critical for wind resistance at the most vulnerable edge of the roof.
Pipe Boot
Metal base flashing with a rubber collar that seals around plumbing vent pipes. The most common source of residential roof leaks; EPDM collars last 8–12 years.
Decking / Sheathing
The structural panel layer (usually 7/16" OSB or 1/2" plywood) nailed to the rafters that forms the substrate for all roofing materials.
Fascia
The horizontal board running along the eave edge of the roof, to which gutters are attached. Wood or aluminum; prone to rot when gutters overflow chronically.
Soffit
The horizontal surface beneath the eave overhang. Soffit vents allow air intake for attic ventilation when combined with ridge vents.
Roof Geometry
Pitch
The slope of a roof expressed as the ratio of rise to horizontal run over 12 inches. A "6:12 pitch" rises 6 inches for every 12 inches of horizontal distance.
Square
Roofing unit of measure equal to 100 square feet of roof surface. A 2,000 sq ft home typically has 20–27 squares of roof depending on slope and complexity.
Valley
The V-shaped channel where two roof planes meet. High-flow drainage area; most vulnerable to water infiltration and requires special flashing or shingle treatment.
Hip
A sloped roof edge where two adjacent slopes meet at an angle, running diagonally from ridge to eave corner. Hip roofs have four slopes; gable roofs have two.
Ridge
The horizontal peak at the top of a roof where two slopes meet. The ridge line runs the full length of the highest point of a gabled or hipped roof.
Eave
The lower edge of a roof that overhangs the exterior wall. The eave edge is where the bottom course of shingles terminates and where gutters attach.
Rake
The sloped edges of a gable roof at either end — the angled edges perpendicular to the ridge. Rake edges are vulnerable to wind and need proper drip edge and starter strip.
Dormer
A vertical structure projecting from a sloped roof, typically containing a window. Dormer-to-roof junctions are common leak locations requiring step and counter flashing.
Installation and Construction Terms
Tear-Off
Removing existing roofing material down to the deck before installing new material. Required when two layers already exist; adds $1–$2/sq ft to project cost.
Overlay / Re-Cover
Installing new shingles over an existing layer without tear-off. Permitted once (maximum two layers by most codes). Hides the deck condition; not recommended.
Nailing Pattern
The placement, depth, and number of nails per shingle. Four-nail standard vs. six-nail high-wind installation has a major impact on real-world wind resistance.
Nail Zone / Nailing Strip
The manufacturer-specified band on the shingle where nails must be placed for proper installation and warranty validity. Nails above this zone are "high nails" — a common defect.
Cricket / Saddle
A small peaked structure built behind wide chimneys to divert water around the obstruction. Required by code for chimneys wider than 30 inches.
Kickout Flashing
A bent piece of flashing at the bottom of a wall-roof junction that directs water into the gutter rather than behind the siding. Frequently missing; a common cause of wall rot.
Rafter Baffles / Chutes
Plastic or cardboard channels installed between rafters to maintain an airflow path from soffit vents to the attic when insulation is added. Critical for cold-climate ventilation.
Ring-Shank Nail
Nail with ridged shaft that provides dramatically higher pullout resistance than smooth-shank nails. Required for decking in Florida; best practice in hurricane zones.
Insurance and Claims Terms
ACV (Actual Cash Value)
Insurance settlement method that pays the depreciated value of the damaged property — what it was worth at its age, not what it costs to replace.
RCV (Replacement Cost Value)
Insurance settlement method that pays the cost to replace damaged property at today's prices, regardless of the old item's age. The better coverage for roof claims.
Recoverable Depreciation
The difference between ACV and RCV payments that the insurer holds back until repairs are completed and documented. Collect this — it's often $3,000–$6,000 left unclaimed.
Wind/Hail Deductible
A separate, often percentage-based deductible that applies specifically to wind and hail claims. Common in hail-active states; can be 1–3% of insured home value.
Test Square
A 10-square-foot area marked by insurance adjusters on each slope to count qualifying hail impact marks. Minimum impacts per test square required for claim approval.
Supplement
An additional claim submission for legitimate items missed in the adjuster's initial estimate — disposal fees, code upgrades, specific materials. Standard and legitimate practice.
Assignment of Benefits (AOB)
A document signing your insurance claim rights to a contractor. Illegal in most states; never sign one. Associated with inflated claims and fraud.
Appraisal Clause
A policy provision allowing independent appraisers for both parties to resolve disputes about claim amounts without litigation. Valuable when adjuster and contractor scopes diverge.
Public Adjuster
A licensed claims professional who works for the homeowner (not the insurer) to document and negotiate claims. Charges 10–15% of settlement; valuable on large or denied claims.
Ordinance or Law Coverage
Policy endorsement covering the cost of bringing a structure up to current building code during repairs. Pays for code-required upgrades not covered under standard policy.
Damage and Condition Terms
Hail Bruise
Circular impact mark from hail on asphalt shingles — a dark center with displaced granules and a soft, spongy feel indicating fractured fiberglass mat beneath.
Granule Loss
Loss of the ceramic granules that protect asphalt from UV. Natural over time; accelerated by hail, pressure washing, algae, and foot traffic. Exposed asphalt oxidizes rapidly.
Thermal Cycling
Repeated expansion and contraction of roofing materials as temperatures change. A primary mechanism of long-term degradation in cold climates.
Ice Dam
Ice accumulation at a roof's eave caused by heat escaping from the building melting snow that refreezes at the cold eave edge. Forces water back under shingles.
Gloeocapsa Magma
The cyanobacterium that creates black algae streaks on roofs in humid climates. Feeds on limestone filler in shingles; causes granule loss and cosmetic damage.
Alligatoring
Cracked, scaly surface pattern on aged asphalt surfaces — named for alligator skin appearance. Indicates severely oxidized asphalt that has lost volatile oils and is near failure.
Armed with this vocabulary, you can read roofing contracts accurately, participate confidently in contractor conversations, and understand every line in an insurance adjuster's estimate. If you encounter a term not listed here, ask us — we're happy to explain it. (800) 555-0100.