GAF Case Analysis & Practical Application 2 — Questions and Answers
Question 1: A homeowner reports that shingles are lifting at the eaves after a winter storm. The inspector finds no ice dam but notices the drip edge was installed over the underlayment at the eaves. What is the correct fix?
- Add a second layer of underlayment over the drip edge
- Remove and reinstall the drip edge under the underlayment at eaves (Correct answer)
- Apply roofing cement under lifted shingles and re-nail
- Install a heated cable system along the eaves
Correct answer: Remove and reinstall the drip edge under the underlayment at eaves
At eaves, drip edge must be installed under the underlayment so water is directed away from the fascia; at rakes it goes over the underlayment.
Question 2: A GAF-certified contractor is installing Timberline HDZ shingles on a 4:12 pitch roof. The manufacturer requires two layers of underlayment below 4:12. What is the appropriate course of action?
- Proceed with one layer since 4:12 is the threshold (Correct answer)
- Install two layers of underlayment to comply with low-slope requirements
- Upgrade to a different shingle rated for 4:12
- Consult local code only and ignore manufacturer specs
Correct answer: Proceed with one layer since 4:12 is the threshold
A 4:12 pitch meets the standard slope threshold, so a single layer of underlayment is acceptable per GAF installation guidelines.
Question 3: During a post-storm inspection, a contractor notices granule loss concentrated at the north-facing slope of a 10-year-old roof. The south-facing slope looks fine. What is the most likely cause?
- Manufacturer defect in that shingle batch
- UV degradation from prolonged sun exposure on the north slope
- Algae growth and moisture retention causing granule loss on the shaded slope (Correct answer)
- Improper nailing pattern on the north slope only
Correct answer: Algae growth and moisture retention causing granule loss on the shaded slope
North-facing slopes receive less sunlight and stay damp longer, promoting algae/moss growth that loosens granules over time.
Question 4: A contractor is adding a second story to a home. The existing roof valley where the new addition meets the old roof must be rebuilt. Which valley method provides the best performance per GAF recommendations?
- Open metal valley with W-metal flashing (Correct answer)
- Woven closed valley with standard shingles
- Cut closed valley using architectural shingles
- Butted valley with no additional flashing
Correct answer: Open metal valley with W-metal flashing
Open metal valleys with W-metal flashing offer superior water-shedding performance and are preferred by GAF for high-volume water flow areas.
Question 5: A homeowner's insurance adjuster marks storm damage as 'cosmetic only' on a 5-year-old GAF Timberline roof. The contractor believes the dents compromise waterproofing. What is the best next step?
- Accept the adjuster's finding and repair only the cosmetic damage
- Request a GAF field representative inspection to document functional damage (Correct answer)
- Immediately replace the entire roof and bill the homeowner
- File a manufacturer warranty claim directly without the adjuster
Correct answer: Request a GAF field representative inspection to document functional damage
A GAF field representative can provide a third-party technical assessment that documents whether impact damage is functional, supporting a revised insurance claim.
Question 6: A flat-to-low-slope transition on a commercial project requires a change in roofing system. The steep-slope section uses GAF shingles and the low-slope section needs waterproofing. What system should the contractor specify?
- Extend the shingles over the low-slope area with extra nails
- Install GAF EverGuard TPO or similar low-slope membrane on the flat section (Correct answer)
- Use rolled roofing only for the low-slope section
- Apply three layers of standard underlayment on the low-slope area
Correct answer: Install GAF EverGuard TPO or similar low-slope membrane on the flat section
Low-slope areas require a dedicated waterproofing membrane system like TPO; standard shingles are not rated for slopes below the manufacturer minimum.
Question 7: After installing a new GAF roof, the contractor notices the ridge vents are misaligned with the attic baffles, restricting airflow. The home owner hasn't moved in yet. What should the contractor do?
- Leave it as-is since ridge vents still provide some airflow
- Document it and disclose at final walkthrough
- Correct the baffle and ridge vent alignment before project closeout (Correct answer)
- Add more soffit vents to compensate for the restriction
Correct answer: Correct the baffle and ridge vent alignment before project closeout
Proper airflow requires a clear path from intake (soffit) through baffles to exhaust (ridge vent); misalignment must be corrected before job completion.
GAF Case Analysis & Practical Application 2
A homeowner reports that shingles are lifting at the eaves after a winter storm.
The inspector finds no ice dam but notices the drip edge was installed over the underlayment at the eaves.
What is the correct fix?