Residential Building Inspector B1Roof-Ceiling ConstructionHard
An inspector is reviewing the installation of a new roof covering on a residential structure. The roof has a pitch of 1:12. Which of the following roof coverings is permitted for this pitch according to the IRC?
- AWood shingles
- BAsphalt shingles
- CConcrete or clay tiles
- DMineral-surfaced roll roofing
Show answer & explanationAnswer & explanation
Correct answer: D. Mineral-surfaced roll roofing
According to IRC Table R905.1.1, mineral-surfaced roll roofing can be installed on roof pitches as low as 1:12. Asphalt shingles and wood shingles require a minimum 2:12 pitch (with specific underlayment for 2:12 to less than 4:12), and concrete/clay tiles require a minimum 2 1/2:12 pitch.
Why the other options are wrong
- A. Wood shingles require a minimum pitch of 2:12.
- B. Asphalt shingles require a minimum pitch of 2:12.
- C. Concrete or clay tiles require a minimum pitch of 2 1/2:12.
Minimum Roof Pitch by Covering
The lowest allowable slope for a specific type of roof covering to ensure proper drainage and prevent water penetration, as defined by building codes.
- Varies significantly by material.
- Steeper pitches generally allow more material options.
- Low-slope roofs require specialized coverings and installation.
Memory trick: Flat roofs need special coverings; steep roofs have more choices.