Roofing 101

Roof diagram


A layer of material spread over a surface for protection or decoration. Coatings for SPF are generally liquids, semi-liquids, or mastics; spray, roller, or brush applied; and cured to an elastomeric consistency.

Counter Flashing

A piece of metal that is applied to the masonry wall designed to shed water off of the wall and down onto the roof surface.


The section of the roof onto which everything else is placed, Usually plywood.


A conduit used to carry runoff water from the gutter of a building to a lower roof level, or to the ground or storm water runoff system.

Drip Edge

The strip of metal extending out beyond the eaves or rakes to prevent rainwater from rolling around the shingles back onto the wooden portion (fascia) of the house.


The lower edge of a roof (usually overhanging beyond the edge of the house).


Trim board behind the gutter and eaves.


Sheet metal or other material used at junctions of different planes on a roof to prevent leakage.


The triangular upper part of a wall closing the end of a ridged roof.


A channeled component installed along the down-slope perimeter of a roof to convey runoff water from the roof to the downspouts.


The external angle at the junction of two sides of a roof whose supporting walls adjoin.

Modified bitumen

An asphalt roll (resembling shingles) designed for low sloped roofs.


The slanting edge of a gabled roof extending beyond the end wall of the house.


The horizontal line at the top edge of two sloping roof planes.

Ridge Vent

A ventilator located at the ridge that allows the escape of warm and/or moist air from the attic area or rafter cavity.

Roof Penetrations

Any object passing through the roof.

Roofing Tune Up

A regular roof tune-up is similar to getting a car tune-up, includes a roof inspection and sealant applied to any exposed fasteners throughout the roof field. Routine maintenance extends the roof life (should be completed every 2 years.)

R-panel Metal Roof

R-panel sheets are 3’ wide with major ribs 12’ on center and panels are installed with fasteners that penetrate the panel and attached to the substrate or structural members below.


Usually made of asphalt, shingles are small, rectangular, and are overlapped when installed to keep water out.


The number of inched of vertical rise in a roof per 12-inches of horizontal distance. Also referred to as pitch.


The boards that enclose the underside of that portion of the roof which extends out beyond the sidewalls of the house.

Roofing Square

One roofing square is equal to one hundred square feet.

Standing Seam
Metal Roof

A metal roof system that consists of an overlapping or interlocking seam that occurs at an upturned rib. The standing seam may be made by turning up the edges of two adjacent metal panels and overlapping them, then folding or interlocking them in a variety of ways.

Step Flashing

Individual pieces of sheet metal material used to flash walls, around chimneys, dormers and such projections along the slope of a roof.


The material (usually roofing felt) laid on top of sheathing before shingles are applied.


The less-than 180-degree angle where two sloping roof sections come together.

Valley Metal

Flashing that is placed in a valley to create an impermeable seal under shingles.


An opening designed to convey air, heat, water vapor or other gas from inside a building or a building component to the atmosphere.

Pipe Boots

A type of roof flashing used around plumbing exhaust pipes that exit through the roof.

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