CA C-39 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 roofing square equals 100 square feet of roof surface. Contractors use squares to estimate shingles, underlayment, and labor quantities.

Asphalt shingle slope limit

Asphalt shingles generally require a minimum roof slope of 2:12. Slopes from 2:12 up to 4:12 need double underlayment under the shingles.

Low-slope roof

A roof with a slope of 3:12 or less. It typically uses membranes such as modified bitumen, EPDM, TPO, or built-up roofing rather than shingles.

Underlayment side lap

Asphalt-saturated felt underlayment commonly laps 2 inches at side seams and 4 inches at end seams for No. 15 felt; always follow the manufacturer's printed instructions.

Roof ventilation ratio

IRC generally requires 1 square foot of net free ventilation per 150 square feet of attic floor area; balanced vents and a vapor retarder may allow 1 per 300.

Step flashing

L-shaped metal flashing installed at a roof-to-sidewall intersection, woven with each shingle course, to direct water onto the roof surface and prevent wall penetration.

Cool roof rating

The Cool Roof Rating Council rates roof products for solar reflectance and thermal emittance. California Title 24 compliance often requires CRRC-listed products meeting climate-zone values.

Roof slope ratio

Slope is vertical rise divided by horizontal run, usually written as rise per 12 inches of run. A 6:12 roof rises 6 inches for every 12 inches horizontal.

Slope factor

For a roof with rise r per 12 inches of run, the slope factor is the square root of 1 plus (r/12) squared. Multiply footprint area by it.

Roof live load

The load from occupancy, snow, and maintenance personnel on a roof. Residential code commonly sets a 20 psf minimum, subject to code reductions and local amendments.

Collar tie

A horizontal framing member connecting opposing rafters in the upper third of the attic. It helps resist rafter separation and uplift but is not a substitute for proper rafter ties.

Ridge beam

A structural beam at the roof peak that carries rafter loads to posts or walls. Unlike a ridge board, it is designed by a qualified person for bending and deflection.

Truss modification rule

Roof trusses may not be cut, notched, or altered without approval from a licensed engineer or the truss manufacturer. Field modifications can void the truss design and compromise safety.

Plan scale

A drawing scale such as 1/4 inch equals 1 foot converts measured drawing distances to real dimensions. Verify the stated scale before scaling any plan.

Roof area takeoff

Calculate horizontal footprint area, multiply by the slope factor, then add waste and penetrations. Convert the result to roofing squares by dividing by 100.

Waste factor

Extra material allowance for cuts, overlaps, and damaged pieces. Simple gable roofs often use 5 to 10 percent; complex hip and valley roofs may need 10 to 15 percent.

Shingle bundle coverage

Three-tab asphalt shingles commonly cover about one-third of a square per bundle, so three bundles cover one square. Architectural shingle coverage varies by manufacturer.

Addendum

A written modification to bid documents issued before the bid deadline. Bidders must acknowledge it, and it becomes part of the contract documents.

Change order

A written agreement signed after contract execution that changes scope, price, or schedule. It should be signed before the changed work proceeds to avoid disputes.

Markup versus margin

Markup is profit divided by cost. Margin is profit divided by selling price. A 20 percent markup yields a 16.7 percent margin, so do not confuse the two.

Cal/OSHA fall trigger

California construction employers generally must provide fall protection when employees are exposed to falls of 7.5 feet or more. Always follow the current Title 8 standard.

Ladder setup angle

Extension ladders should be set at about a 4:1 ratio, meaning 1 foot out for every 4 feet of working height, and extend 3 feet above the landing.

Guardrail height

A standard guardrail has a top rail about 42 inches above the walking surface, a midrail, and toe boards where required. Openings must not allow a fall.

Hot work permit

A written authorization for welding, grinding, or torch work that specifies fire precautions, a fire watch, and clearance from combustibles. It helps prevent roof fires.

Personal fall arrest

A system using a full-body harness, lanyard, and anchor rated at 5,000 pounds or engineered equivalent. It must limit free fall and include prompt rescue planning.

Asphalt kettle safety

Keep roofing asphalt kettles covered, temperature-controlled, and away from combustibles. Provide a fire extinguisher and train workers to avoid burns and fume exposure.

License threshold

California generally requires a contractor license for projects of $500 or more in labor and materials. The threshold applies to the combined contract price, not labor alone.

Down payment limit

On California home improvement contracts, the down payment may not exceed 10 percent of the contract price or $1,000, whichever is less.

Preliminary lien notice

A contractor generally must serve a preliminary notice on the owner and lender within 20 days after first furnishing labor or materials to preserve mechanic's lien rights.

Workers compensation

California employers must carry workers' compensation insurance for employees. A contractor may need to provide a certificate or exemption before starting work.

Bid bond

A bond submitted with a bid, often 10 percent of the bid amount, guaranteeing the bidder will enter the contract if awarded.

Conditional lien release

A document stating that a progress or final payment is conditioned on receipt of funds. It releases lien rights only when the payment actually clears.