CSLB C-39 Roofing ContractorSafety and RepairEasy
A roofing contractor is preparing to reroof a single-family dwelling in California. The existing roof has two layers of asphalt shingles. What is the maximum number of shingle layers permitted by California Building Code (CBC) before a complete tear-off is required?
- ATwo layers
- BThree layers
- CFour layers
- DOne layer
Show answer & explanationAnswer & explanation
Correct answer: A. Two layers
The California Building Code (CBC) generally limits the number of shingle layers to two. If a roof already has two layers, a complete tear-off of all existing roofing materials is required before installing new shingles.
Why the other options are wrong
- B. Three layers exceed the typical CBC allowance for asphalt shingles without a tear-off.
- C. Four layers is well beyond the permitted limit and would necessitate a tear-off.
- D. One layer is the ideal, but two are often permitted. This option is too restrictive.
CBC Shingle Layer Limit
The California Building Code (CBC) generally limits asphalt shingle roofs to a maximum of two layers before a complete tear-off is required.
- Applies to asphalt shingles.
- Prevents excessive weight load on structure.
- Ensures proper substrate for new roofing.
Memory trick: Two layers are fine, but three means tear-off time.