Quality Control
Roofing Vent Installation & Flashing
Install roof vents with proper counter-flashing to prevent leaks.
10 min James O'Brien Reviewed by Frank Marlow, Master Roofer v1.1 · reviewed 2026-06-14
The Problem
Vents installed without proper counter-flashing cause chronic leaks and result in warranty callbacks and interior damage.
Root Causes
- Vent flashings installed on top of membrane instead of woven in
- Sealants substituted for mechanical flashings
- No pull-test performed after installation
Correct Procedure
- 1Set vent on primer per manufacturer instructions
- 2Weave base flashing under upslope shingles/membrane
- 3Storm collar and counter-flashing installed above
- 4Seal all fastener heads with compatible sealant
- 5Water-test the assembly before roof handover
Prevention Steps
- Foreman verifies photo before covering with next course
- Maintain a punch-list of every roof penetration on the project
Discussion Questions
Use these to engage the crew and connect the lesson to today's site conditions.
- 1What can go wrong if we don't weave the flashing?
- 2How do we water-test after install?
Sources & Review
Author: James O'Brien (25+ yrs) · Reviewed by Frank Marlow, Master Roofer.
Published 2024-03-11 · Last technical review 2026-06-14 · Version 1.1 · Languages: EN, ES
AI at QST only summarizes expert-approved content and never invents safety requirements.
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