Plain-English Glossary
Roofing terms, in plain English.
We explain every quote we write in plain language. This page defines the words other roofers throw around — so you can read any bid, inspection report, or warranty and know exactly what you're agreeing to.
Roof anatomy
The parts of the roof, from the ridge down to the gutter line.
Ridge
The horizontal line at the very top of your roof, where the two main slopes meet.
Where you'll hear it: In ventilation talk — “we'll cut in a ridge vent” — and in the line item “hip and ridge.”
Ridge cap
The row of shingles or metal that covers and seals the ridge. It takes more wind than any other part of the roof.
Where you'll hear it: Near the end of a quote, usually written as “hip and ridge cap.”
Hip
A sloped outside corner where two roof planes meet, running from the ridge down to the gutter line. A hip roof slopes on all four sides.
Where you'll hear it: In “hip and ridge” line items. Hip roofs use more material than simple two-slope roofs.
Valley
The inside channel where two roof slopes drain into each other. Valleys carry the most water on the roof, so they get extra protection.
Where you'll hear it: “Open valley” means the metal liner shows. “Closed valley” means shingles cover it.
Eave
The lower edge of the roof, where it overhangs the outside wall. The gutters hang here.
Where you'll hear it: “Ice and water shield at the eaves” or “eave flashing” in a quote.
Rake
The sloped edge of the roof at the end wall of the house — the edge that runs uphill.
Where you'll hear it: “Drip edge on all eaves and rakes.”
Gable
The triangle of wall under a peaked roof's two slopes. A gable roof is the classic two-slope roof shape.
Where you'll hear it: “Gable vent” — a louvered vent set into that wall triangle.
Dormer
A small roofed structure that sticks up out of the main roof, usually holding a window. Every dormer adds flashing work.
Where you'll hear it: “We'll re-flash both dormers” on replacement quotes.
Fascia
The flat trim board that runs along the roof edge. It is the board your gutter is screwed into.
Where you'll hear it: “Dry rot in the fascia” — common where gutters have overflowed for years.
Soffit
The panel that covers the underside of the roof overhang — stand at the wall, look straight up, and you are looking at soffit. It usually holds the attic's intake vents.
Where you'll hear it: “Soffit vents” whenever attic ventilation comes up.
Decking (sheathing)
The wood panels — usually plywood or OSB (oriented strand board, an engineered wood panel) — nailed across the rafters. Every other roofing layer sits on the decking.
Where you'll hear it: In the fine print of a quote: “decking replacement billed per sheet.”
Skip sheathing
Older decking made of boards with gaps between them instead of solid panels. It usually needs solid plywood installed over it before a modern roof can go on.
Where you'll hear it: On older homes that originally had wood shake roofs — the gaps let those roofs breathe.
Pitch (slope)
How steep the roof is, written as inches of rise per 12 inches of run. A 6/12 pitch climbs 6 inches for every foot it travels.
Where you'll hear it: “Your pitch is 4/12” — steeper roofs take more safety gear and more time.
Low-slope
A roof that is nearly flat — generally a 3/12 pitch or less. Shingles cannot seal reliably at that angle, so low-slope roofs use membrane systems instead.
Where you'll hear it: “The patio section is low-slope, so it gets a different material” — see TPO, EPDM, and modified bitumen below.
Materials & components
What actually goes on the roof — and what each layer is for.
Underlayment
The water-resistant sheet installed over the decking, under the shingles. It is the backup layer if wind-driven rain ever gets past the top layer.
Where you'll hear it: “Synthetic underlayment” — the modern upgrade over old-style felt (tar paper).
Ice & water shield
A sticky-backed rubber membrane used in leak-prone spots: valleys, around chimneys and pipes, and along some edges. Unlike plain underlayment, it self-seals around nail holes.
Where you'll hear it: “Ice and water in all valleys” on a thorough quote.
Drip edge
The L-shaped metal strip installed along the roof edges. It guides runoff into the gutter instead of behind it, where water would rot the fascia.
Where you'll hear it: Building code requires it on most new shingle roofs, and insurance supplements often add it on claims.
Flashing
Thin metal formed to waterproof the joints where the roof meets anything else — walls, chimneys, skylights, pipes. Most leaks start at flashing, not in the open field of the roof.
Where you'll hear it: Worth asking every bidder: “Are you replacing the flashing or reusing it?”
Step flashing
Small L-shaped metal pieces woven in with each row of shingles where the roof runs along a wall. Each piece steps up the slope with the shingles.
Where you'll hear it: “Step flash the sidewalls” — the right way to seal a roof-to-wall joint.
Kickout flashing
The small angled piece at the bottom of a roof-to-wall joint that kicks water away from the wall and into the gutter. When it is missing, water can run down inside the wall for years before anyone notices.
Where you'll hear it: Home inspectors flagging “missing kickout flashing.”
Pipe boot
The rubber-and-metal collar that seals around the plumbing vent pipes poking through your roof. The rubber cracks in the sun, which makes pipe boots one of the most common small-leak repairs.
Where you'll hear it: “We replace every pipe boot on a re-roof” — they should not be reused.
Starter strip
The first strip of shingle material installed along the edges, underneath the first visible row. It glues the edge shingles down against wind lift.
Where you'll hear it: A small line item on the quote — skipping it is a corner-cutting red flag.
Architectural shingle
Today's standard asphalt shingle. It is built in layers for a thicker, dimensional look and carries higher wind ratings than the old flat style. Also called laminate or dimensional shingles.
Where you'll hear it: Product names like GAF Timberline or CertainTeed Landmark.
3-tab shingle
The older, flat, single-layer asphalt shingle, cut so each strip looks like three tabs. Thinner and shorter-lived than architectural shingles — now used mostly to match existing older roofs.
Where you'll hear it: “They don't make your 3-tab color anymore” during repairs on aging roofs.
Granules
The crushed, coated stone on a shingle's surface. Granules block sunlight (UV) from cooking the asphalt underneath — once they shed, the shingle ages fast.
Where you'll hear it: “Check your gutters for granules” — a classic sign a roof is near the end.
Class A fire rating
The highest fire-resistance rating a roof covering can earn. California requires Class A roofing in designated high fire-hazard zones.
Where you'll hear it: In WUI areas (wildland-urban interface — where homes meet open wildland). Our wildfire roofing guide covers it in depth.
Cool roof (Title 24)
A roof surface designed to reflect more sunlight and shed heat faster. Title 24, California's energy code, requires cool-roof products in many climate zones — mostly on low-slope roofs and some re-roofs.
Where you'll hear it: “That color isn't Title 24 compliant” when picking shingle colors.
TPO
A single-ply plastic membrane (thermoplastic polyolefin — a heat-weldable plastic sheet) used on flat and low-slope roofs, usually white. Its seams are welded together with hot air, not glued.
Where you'll hear it: Flat-roof and commercial quotes — “60-mil TPO” describes its thickness.
EPDM
A single-ply rubber membrane — the black one — for flat and low-slope roofs. Its seams are glued or taped, and the rubber stays flexible for decades.
Where you'll hear it: Many roofers just call it a “rubber roof.”
Modified bitumen
Asphalt rolled roofing with rubber or plastic blended in so it flexes instead of cracking. It goes down in overlapping rolls on low-slope roofs.
Where you'll hear it: “Mod bit” for short — common over garages and patios.
Torch-down
A way of installing modified bitumen: the installer heats the underside of the roll with a torch so it melts and bonds to the layer below.
Where you'll hear it: “Torch-down roof” used as the product name for low-slope sections.
Standing seam
A metal roof made of long vertical panels that lock together at raised seams. The fasteners hide under the seams, so no screw heads are exposed to the weather.
Where you'll hear it: Metal roofing quotes — it costs more than screw-down metal because of that hidden-fastener design.
Ridge vent
A low-profile vent running the length of the ridge that lets hot attic air escape. It is the exhaust half of the attic ventilation system.
Where you'll hear it: “Cut in a ridge vent” during replacements — paired with soffit vents.
Process & repair
Words you'll hear while the job is being planned and done.
Square (the unit)
Roofing's unit of measurement: one square equals 100 square feet of roof surface. A typical single-family home runs somewhere in the 20-to-30-square range.
Where you'll hear it: All over your quote — “tear-off and re-roof, 24 squares.”
Tear-off
Removing all the old roofing down to bare decking before the new roof goes on. It is the only way to see — and fix — the wood underneath.
Where you'll hear it: “Full tear-off” versus “overlay” — the first big fork in any replacement quote.
Overlay (re-roof over)
Installing new shingles directly on top of the old ones, skipping the tear-off. It is cheaper up front but hides decking problems, and building code generally caps a roof at two layers.
Where you'll hear it: “Can't you just go over it?” — sometimes yes, often not worth it.
Re-deck
Replacing the wood decking itself, not just what sits on top of it. Needed when panels are rotten or coming apart, or when old skip sheathing cannot hold modern roofing.
Where you'll hear it: “Re-deck with new plywood” as a change order after tear-off.
Dry-in
Getting the roof watertight with underlayment and flashing before the finish roofing is installed. Once a roof is dried in, the house is protected even if the shingles wait a day.
Where you'll hear it: “We'll dry it in today and shingle tomorrow” — normal sequencing, not a delay.
Dry rot
Wood decay caused by a fungus in damp wood. The name misleads — it needs moisture to start. It shows up in decking, fascia boards, and rafter tails.
Where you'll hear it: “Dry rot repair” billed as carpentry, priced per foot or per sheet.
Ponding
Rainwater still sitting on a flat roof a day or two after the storm has passed. Standing water ages a membrane fast and can void its warranty.
Where you'll hear it: Flat-roof inspection reports — “evidence of ponding near the drain.”
Attic ventilation (intake & exhaust)
The flow of air through your attic: cool air enters low through the soffit vents (intake) and hot air exits high at the ridge (exhaust). Poor ventilation overheats shingles from below and can shorten a roof's life.
Where you'll hear it: “Your intake and exhaust are out of balance” during inspections.
Paperwork & warranty
Contract, insurance, and warranty fine print — read these twice.
Scope of work
The contract section that lists exactly what the roofer will and will not do. If something is not written in the scope, it is not included in the price.
Where you'll hear it: When comparing bids — match them scope line by scope line, not by the bottom number.
Change order
A written amendment to the contract when the job changes after signing — for example, hidden dry rot found during tear-off. It should state the added work and the added price before that work starts.
Where you'll hear it: “We'll write a change order for the bad decking.”
Supplement (insurance)
A request your roofer files with your insurance company to cover items the adjuster's first estimate missed. Common on storm claims.
Where you'll hear it: “We'll supplement for the drip edge and code items.” Our insurance claim guide walks through the process.
Deductible (insurance)
The share of an insurance claim you pay out of pocket before coverage kicks in. A contractor who offers to eat or hide your deductible is waving a fraud red flag.
Where you'll hear it: Storm-claim sales pitches — honest roofers don't play games with deductibles.
Material warranty
The manufacturer's coverage against defects in the roofing product itself. It does not cover installation mistakes — that is what a workmanship warranty is for.
Where you'll hear it: “Lifetime shingles” — read what “lifetime” actually covers, and for how long.
Workmanship warranty
The roofer's own promise covering installation errors. It is only as good as the company behind it, so the contractor's track record matters more than the number of years.
Where you'll hear it: “Ten-year workmanship warranty” in a bid — ask who honors it if the company closes.
Prorated warranty
Coverage that shrinks as the roof ages — the older the roof, the smaller the share the manufacturer pays. Many lifetime warranties switch to prorated coverage after an initial full-coverage window.
Where you'll hear it: Warranty brochures' fine print — look for the proration schedule.
System (enhanced) warranty
An upgraded manufacturer warranty offered only when a certified contractor installs the brand's full matching system of components. Examples include GAF Golden Pledge and CertainTeed SureStart PLUS — both available through NuShake as a certified installer.
Where you'll hear it: “Registered” or “enhanced” warranty options at quote time — they require certification, so ask to see it.
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