Core TradesQuestion 202 of 700
Proper flashing where a masonry chimney passes through a sloped roof generally consists of:
a.A single continuous sheet wrapped around the chimney
b.Only sealant applied at the roof-to-chimney joint
c.Roofing cement troweled over the shingles
d.Base (apron and step) flashing combined with counter (cap) flashing let into the masonry
Explanation
Durable chimney flashing uses base flashing on the roof plane plus counter (cap) flashing set into the masonry joints to overlap it, so water is shed at two layers. A single wrap, sealant alone, or roofing cement over shingles cannot accommodate movement and will eventually leak.
Law Reference: 2025 CA Residential Code, Chapter 9 (Roof Assemblies)Practice all 700 questions free — no signup required.
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