Chimney Flashings Flashcards
What are the five types of chimney flashings?
1.Step flashing
2.Counter-flashing
3.Apron flashing
4.Cricket flashing
5.Backer flashing
Where is step flashing installed, and how is it designed?
Step flashing is installed where the roof intersects a vertical sidewall, with individual pieces of metal stepping up with each shingle course.
What is the purpose of counter-flashing?
Counter-flashing protects the top edges of other flashings to prevent water intrusion.
Where is apron flashing typically installed?
Apron flashing is used where a roof intersects a headwall, such as the downslope side of a dormer or a chimney.
What is the function of cricket flashing?
Cricket flashing diverts water around chimneys or roof penetrations. It is recommended for chimneys wider than 24–30 inches.
When is backer flashing used?
Backer flashing is installed on the upslope backside of narrow chimneys (less than 24 inches) that do not require a cricket.
What is a common defect associated with missing counter-flashing?
Missing counter-flashing exposes the top edge of step flashing to water penetration, often sealed temporarily with non-standard sealant.
How should counter-flashing be installed on masonry chimneys for best practice?
The top edge of counter-flashing should be inserted at least 1 inch into the masonry joint or a groove cut in the masonry.
What is a defect if a chimney wider than 24 inches lacks cricket flashing?
Without cricket flashing, water is not diverted properly, even if backer flashing is installed, making it a defect.
What does sealed valleys on a cricket indicate, and why is this poor practice?
Sealed valleys with roofing sealant indicate water intrusion problems. Sealant is not a permanent solution and is considered poor practice.
