AZ Roofing Contractor flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Roofing square

A unit of roof area equal to 100 square feet. Most asphalt shingles are packaged three bundles per square, and estimates, takeoffs, and warranties are usually stated in squares.

Minimum asphalt shingle slope

Asphalt shingles require at least a 2:12 slope. From 2:12 to 4:12 a double layer of underlayment is required, and below 2:12 shingles are not permitted at all.

Class A fire rating

A rating for a roofing assembly showing resistance to severe external fire exposure. Fiberglass asphalt shingles over listed underlayment commonly achieve it, and many codes require it.

Dead load of tile

Concrete and clay tile roofs weigh roughly 9 to 12 pounds per square foot, so the structure must be engineered for that load, unlike asphalt shingles at about 3 psf.

Panel span rating

A number stamped on plywood or OSB, such as 24/16, giving maximum support spacing in inches for roof and floor use. It must meet or exceed the rafter spacing.

Ice dam protection membrane

A self-adhering waterproof underlayment installed along eaves where the January mean temperature is 25 degrees F or lower. It extends at least 36 inches from the eave edge.

Underlayment lapping

Felt underlayment is lapped 2 inches on side laps and 4 inches on end laps, installed shingle-fashion so each upper strip overlaps the strip below it.

Sheathing edge gap

A 1/8-inch space left between adjacent roof deck panels to allow for expansion. Panel end joints must still land on and be fastened to framing members.

Shingle nailing placement

Fasteners go in the manufacturer's nail line, 1/4 to 1 inch above the exposure line and about 3/4 inch from each end, penetrating the deck at least 3/4 inch.

Slate headlap

The vertical overlap between slate courses: 3 inches for roofs between 4:12 and 8:12, reduced to 2 inches on slopes steeper than 8:12.

Starter course

The first row at the eave, installed as a manufactured strip or reversed shingle, sealing the butt joints of the first exposed course and finishing the eave at the drip edge.

Standing seam thermal movement

Metal panels expand and contract with temperature, roughly 1/8 inch per 10 feet per 10 degrees F change. Clips and end details must allow movement without stressing seams.

EPDM membrane

A thermoset rubber single ply usually 45 or 60 mil thick, seamed with splice adhesive or butyl tape. It resists UV and ozone well, but seams are its most common failure point.

TPO heat welding

Thermoplastic polyolefin seams are joined with hot air at roughly 500 to 1,000 degrees F, producing a fused weld that exceeds the membrane strength when properly executed.

SBS versus APP modified bitumen

SBS is elastomeric, stays flexible in cold, and can be torch-applied, hot-mopped, or cold-adhered. APP is plastomeric, more heat resistant, and usually torch-applied.

Low-slope definition

A roof with a slope at or below 3:12. The minimum practical drainage slope is 1/4:12, about 2 percent, and drainage never relies on the membrane alone.

Step flashing

L-shaped metal pieces woven into each shingle course where a roof meets a sidewall. Each piece is at least 4 by 4 inches and laps the piece below by 2 inches.

Cricket requirement

A peaked diverter built on the uphill side of a chimney or curb wider than 30 inches to split water flow around the obstruction and prevent ponding and leakage.

Counterflashing

Metal set in a reglet in a wall or curb and lapped at least 1 inch over the base flashing, so water running down the wall cannot get behind the roof membrane.

Kick-out flashing

An angled diverter at the bottom of a roof-to-wall intersection that throws water away from the wall and into the gutter instead of letting it run down the siding.

Attic ventilation ratio

Net free vent area must be at least 1/150 of the attic floor area, or 1/300 with a Class I or II vapor retarder, with 40 to 50 percent at the upper vents.

Pitch to area factor

A multiplier converting plan area to sloped roof area: 1.054 at 4:12, 1.118 at 6:12, 1.202 at 8:12, and 1.414 at 12:12.

Vent baffle

A rigid channel installed at the eaves that keeps insulation from blocking the soffit intake and maintains about a 1-inch air space under the roof deck.

Hail damage versus blister

Hail leaves random, soft bruises with a fractured mat and displaced granules. Blisters are raised, circular, unadhered areas caused by trapped moisture or volatiles, not impact.

Core sample

A circular cut taken through a low-slope roof that reveals ply count, insulation type and thickness, and whether moisture is present in the assembly.

Membrane seam repair

Open single-ply seams are cleaned, primed, and re-welded or covered with a splice. An opening wider than about 1/2 inch cannot be corrected with sealant alone.

Pitch multiplier use

A factor applied to the building footprint to obtain true roof area. A 6:12 roof uses 1.118, so 2,000 square feet of plan area becomes about 2,236 square feet.

Waste factor

Extra material added to a takeoff for cuts and errors: about 10 percent for simple gable roofs and 15 percent or more for hip roofs with valleys and penetrations.

Drawing scale

The ratio between paper dimensions and field dimensions. At 1/4 inch equals 1 foot, one inch measured on the drawing represents 4 feet of actual construction.

Six-foot fall rule

OSHA requires fall protection for construction workers exposed to falls of 6 feet or more, which covers nearly all roof work above a single story.

Warning line system

A rope or chain with high-visibility flags set at least 6 feet from the roof edge on low-slope roofs, used with guardrails or a safety monitor; equipment stays 10 feet back.

Fire watch

A person assigned to watch for fire during torch work or kettle operations and for at least 30 minutes afterward, with charged extinguishers immediately available.