- Apron flashing
- The metal piece at the bottom of a chimney or a wall where it meets the roof. It carries water out onto the roof surface.
- Architectural shingle
- A laminated asphalt shingle built in two or three layers. It reads thicker than a three tab shingle and lasts longer.
- Base sheet
- The first ply of a built up or modified bitumen roof. It is fastened to the deck and everything else bonds to it.
- Batten
- A wood strip run across the roof that tile hangs on. Battens lift the tile and let air move under it.
- Bird stop
- A closure at the eave that fills the gap under the first course of tile. It keeps birds, debris and wind blown embers out.
- Blister
- A raised bubble in a membrane roof caused by trapped moisture or air. Blisters grow in heat and eventually split.
- Boot
- The collar that seals around a plumbing vent pipe. The rubber type cracks in sun in about ten years.
- Built up roof
- A flat roof made of several layers of asphalt and felt, often topped with gravel. It is the classic tar and gravel roof.
- C 39
- The California license classification for roofing contractors.
- Cap sheet
- The top ply of a modified bitumen roof, usually with mineral granules on the surface.
- Class A
- The highest fire rating for a roof assembly. It is required in high fire severity zones.
- Closed valley
- A valley where the roofing material runs across the joint and covers the metal underneath.
- Cool roof
- A roof surface rated to reflect sunlight and release heat. California energy rules ask for one on many reroofs.
- Counter flashing
- The upper flashing set into a wall or chimney that covers the top edge of the base flashing.
- Course
- One row of roofing material running across the roof.
- Cricket
- A small ridged structure built behind a chimney or curb to split water and send it around the obstruction.
- CRRC
- The Cool Roof Rating Council. It tests and publishes the reflectance and emittance numbers used for code compliance.
- CSLB
- The Contractors State License Board, the California agency that licenses and disciplines contractors.
- Deck
- The wood surface over the rafters that the roof is built on. Plywood, board sheathing or oriented strand board.
- Dormer
- A framed projection with its own small roof that sticks out of a sloped roof.
- Drip edge
- Metal at the eave and rake that pushes water off the edge instead of letting it curl back into the fascia.
- Eave
- The lower edge of a roof, usually overhanging the wall.
- Emittance
- How well a surface releases the heat it absorbs. One of the two numbers on a cool roof label.
- Exposure
- The part of a shingle or tile left visible after the next course laps over it.
- Fascia
- The flat board at the roof edge that gutters usually hang from.
- Felt
- Asphalt saturated paper used as underlayment. Sold in fifteen and thirty pound weights.
- Field
- The main open area of a roof, away from edges and penetrations.
- Flashing
- Sheet metal shaped to bridge a joint in a roof. Most leaks start here.
- Gable
- The triangular wall section at the end of a ridged roof.
- Granules
- The mineral coating on a shingle or cap sheet. It blocks sun and sets the color and the fire rating.
- Hip
- The outside corner where two roof planes meet and slope away from each other.
- Ice and water shield
- A self adhered membrane that seals around fasteners. In Los Angeles it is used at eaves and valleys rather than for ice.
- Lift and relay
- Taking tile off, replacing the underlayment and flashing, and setting the same tile back down.
- Low slope
- A roof at 2 in 12 pitch or less. It needs a membrane system rather than shingles.
- Membrane
- A single sheet system such as TPO, PVC or modified bitumen that waterproofs a flat roof.
- Modified bitumen
- Asphalt roofing modified with rubber or plastic and installed in rolls, often torch applied.
- Net free area
- The real open area of a vent after screens and louvers, given in square inches. Ventilation math uses this number.
- Open valley
- A valley with exposed metal down the center and the roofing cut back on both sides.
- Oriented strand board
- An engineered wood panel used for decking. It swells badly once it gets wet.
- Overflow drain
- A second drain or scupper set above the primary one that carries water off when the primary clogs.
- Parapet
- A wall that extends above the roof line on a flat roof.
- Penetration
- Anything that passes through the roof surface, such as a pipe, a vent or a mount.
- Pitch
- The slope of a roof, given as rise over twelve inches of run.
- Ponding
- Water still standing on a low slope roof more than 48 hours after rain.
- Purlin
- A horizontal framing member that supports roofing on a structure with no solid deck.
- Rafter
- A sloped framing member running from the ridge to the wall that carries the deck.
- Rake
- The sloped edge of a roof at a gable end.
- Reflectance
- The share of sunlight a roof surface bounces back. The other key number on a cool roof label.
- Ridge
- The horizontal peak where two roof planes meet at the top.
- Ridge vent
- A vent product run along the ridge that lets hot attic air out at the highest point.
- Scupper
- An opening through a parapet wall that lets water off a flat roof.
- Self adhered underlayment
- A peel and stick sheet that bonds to the deck and seals around nails driven through it.
- Shake
- A split wood roofing piece, thicker and rougher than a sawn shingle. Rare on new roofs here because of fire rules.
- Sheathing
- Another name for the roof deck material.
- Single ply
- A membrane roof made of one welded sheet, such as TPO or PVC.
- Skip sheathing
- Spaced boards used as a deck under older tile and shake roofs.
- Soffit
- The underside of a roof overhang. Intake vents usually live here.
- Square
- One hundred square feet of roof area. Roofing is priced by the square.
- Standing seam
- A metal roof where panels lock together at raised ribs and the fasteners are hidden.
- Starter course
- The first row at the eave that the visible first course laps over. It seals the bottom edge.
- Step flashing
- Individual bent pieces of metal, one per course, where a sloped roof meets a wall.
- Tapered insulation
- Insulation cut in a slope and laid under a membrane to build fall toward a drain.
- Tear off
- Removing the old roof down to the deck before the new one goes on.
- Three tab
- A flat single layer asphalt shingle with cutouts. The cheapest shingle and the shortest lived.
- TPO
- Thermoplastic polyolefin, a white single ply membrane welded at the seams with hot air.
- Underlayment
- The sheet laid over the deck under the roof covering. On a tile roof it is the real waterproof layer.
- Valley
- The inside angle where two roof planes meet. It carries the most water on a roof.
- Vapor drive
- Moisture moving through a roof assembly with temperature. It is why attics need to breathe.
- Waste factor
- The extra material bought to cover cuts and offcuts. Eight to fifteen percent is normal.
- Weep hole
- A small opening left to let trapped water out of a flashing or a wall assembly.