Roofing Terms Glossary — Read any roofing estimate with confidence.
Roofing terms can make an estimate hard to follow. This glossary explains the words roofers use in plain English, from the parts of a roof to the materials, the problems we find and the paperwork, so you can read a scope and ask the right questions.
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Parts of a roof
- Roof deck (sheathing)
- The layer of plywood or boards fastened to the rafters that everything else is built on. A full tear-off exposes it, so damaged sections can be replaced before the new roof goes on.
- Rafters and trusses
- The wood framing that holds up the roof deck and sets the shape and slope of the roof.
- Underlayment
- The water-resistant layer between the roof deck and the shingles, tile or metal. It is the roof’s second line of defense, and on a tile roof it does most of the waterproofing.Read more
- Ridge
- The top edge where two roof slopes meet. It is covered with ridge caps.
- Hip
- The sloped edge where two roof planes meet on the outside of a corner, running from the ridge down to the eave.
- Valley
- The channel where two roof slopes meet on the inside of a corner. Valleys carry a lot of water, so they are a common place for leaks and debris.
- Eave
- The lower edge of a roof that hangs past the wall.
- Rake
- The sloped outer edge of a gable roof, from the eave up to the ridge.
- Gable
- The triangle of wall at the end of a pitched roof. A gable roof slopes down on two sides; a hip roof slopes down on all four.
- Fascia
- The board along the eave that the roof edge finishes against.
- Soffit
- The underside of the eave overhang. Soffit vents let air into the attic.
- Penetration
- Anything that passes through the roof: plumbing vents, exhaust fans, skylights, chimneys, solar mounts or equipment supports. Each one has to be flashed and sealed.
- Parapet
- A low wall that rises above the edge of a flat roof, common on Spanish-style homes and commercial buildings.
- Coping
- The cap along the top of a parapet wall that keeps water out of the wall itself.
- Scupper
- An opening in a parapet wall that lets water run off a flat roof.
- Cricket (saddle)
- A small peaked section built behind a chimney or between slopes to steer water around it instead of letting it pool.
Flashing and details
- Flashing
- Metal or membrane pieces that seal the joints where the roof meets a wall, chimney, skylight, vent or another roof plane. Most leaks start at flashing, not in the middle of a roof.Read more
- Step flashing
- Small L-shaped pieces woven in with each course of shingles where a sloped roof meets a wall.
- Counter flashing
- Flashing set into the wall or chimney that laps over the step or base flashing below it, so water can’t get behind it.
- Drip edge
- A metal strip along the eaves and rakes that guides water off the roof edge and protects the deck’s edge.
- Pipe boot (pipe jack)
- The collar that seals around a plumbing vent pipe. Rubber boots crack in the sun and are one of the most common small leaks on shingle roofs.
- Ridge vent
- A vent that runs along the ridge so warm, moist air can leave the attic.Read more
- Eave closure (bird stop)
- A piece that closes the open ends of the first row of tiles at the eave, keeping out birds, pests and wind-blown embers.
- Battens
- Strips of wood or other material fastened across the roof that some tile roofs hang on.
Measuring a roof
- Square
- Roofers price and order by the square: 100 square feet of roof surface. A 2,000 square foot roof is 20 squares.Read more
- Pitch (slope)
- How steep a roof is, written as the rise in inches for every 12 inches across: a 4/12 roof rises 4 inches per foot. Steeper roofs take more time and safety work.
- Low-slope roof
- A roof that is nearly flat, usually under 3/12. It needs a continuous membrane rather than overlapping shingles or tile.Read more
- Waste factor
- The extra material ordered for cuts, starter rows, hips and ridges, usually given as a percentage of the roof area.
- Roof facet (plane)
- One flat surface of a roof. A simple gable roof has two; a complex roof can have twenty or more, and every extra facet adds cuts, valleys and flashing.
Roofing materials
- Architectural shingle
- A thicker, layered asphalt shingle with a dimensional look. It has largely replaced the flat three-tab shingle on new roofs.Read more
- Three-tab shingle
- A thinner, single-layer asphalt shingle with three flat tabs per strip.
- Starter strip
- The first course of shingles along the eave, which seals the edge and gives the first visible row something to bond to.
- Clay tile
- Fired clay roof tile, the classic Spanish (barrel) or flat profile seen across Southern California. The tile itself can outlast the underlayment beneath it.Read more
- Concrete tile
- Roof tile made from concrete, heavier than clay and made in many profiles and colors.Read more
- Standing seam metal
- A metal roof made of long panels joined by raised seams, with the fasteners hidden under the seams.Read more
- Modified bitumen
- An asphalt roofing membrane strengthened with polymers, laid in rolls on flat roofs. APP and SBS are the two main types.Read more
- Torch-down roofing
- Modified bitumen sheets bonded to the roof by heating them with a torch, so the layers fuse into one waterproof surface.Read more
- Base sheet and cap sheet
- The two layers of a modified bitumen roof: the base sheet goes down first, the cap sheet is the finished, often granulated, top layer.
- TPO
- Thermoplastic polyolefin: a single-ply membrane, usually white, whose seams are welded with hot air. Common on commercial flat roofs.Read more
- Built-up roof (BUR)
- An older flat roof made of alternating layers of asphalt and felt, often finished with gravel.
- Cool roof
- A roof surface that reflects more sunlight and gives off heat more easily than a standard roof, which keeps the roof and the rooms below cooler.Read more
- Class A fire rating
- The highest fire rating a roof covering can get in standard fire tests. Clay and concrete tile, metal and most asphalt shingles can reach it.Read more
Problems we find
- Ponding water
- Water that sits on a flat roof long after rain instead of draining. It wears the surface and finds any weak seam.
- Blister
- A raised bubble in a flat roof membrane where air or moisture is trapped between layers.
- Granule loss
- Asphalt shingles shedding their mineral surface, which leaves the shingle exposed to the sun. Granules washing off the roof and bare, dark patches are signs of an aging roof.
- Nail pop
- A roofing nail that has backed out and lifted the shingle above it, leaving a path for water.
- Slipped tile
- A roof tile that has moved out of place, often because its fastener or the batten under it has failed.
- Wind-lifted shingle
- A shingle whose seal has broken in the wind, so its edge can flap, crease or tear off.Read more
The work and the paperwork
- Tear-off
- Removing the old roofing down to the deck before the new roof goes on, so the deck can be checked and repaired.Read more
- Overlay (re-roof)
- Installing new shingles over an existing layer instead of tearing it off. It hides the deck and adds weight, and the number of layers allowed is limited.
- Lift and relay
- A tile roof repair where the tiles are lifted off, the worn underlayment beneath them is replaced, and the same tiles are put back.Read more
- Scope of work
- The written list of exactly what a roofer will do: materials, details, how damage found during the job is handled and the price. Compare scopes, not just totals.
- Building permit
- Approval from the city or county for the roof work, followed by an inspection. QRS pulls the permits for its jobs.
- Workmanship warranty
- The roofer’s own guarantee on how the roof was installed, separate from the manufacturer’s warranty on the materials. QRS backs its installs with a 10-year workmanship warranty.
- Manufacturer’s warranty
- The material maker’s warranty on its products. The coverage depends on the product and the warranty tier.
- CSLB license
- California’s Contractors State License Board licenses roofers. You can look up any contractor’s license number on the CSLB website before you hire.Read more
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