GAF Case Analysis & Practical Application 3 — Questions and Answers
Question 1: A customer wants to re-roof over an existing layer of 3-tab shingles. The deck shows no rot, but the existing shingles have cupping. What is the correct approach per best practices?
- Install new shingles directly over the cupped layer
- Tear off the existing layer before installing new shingles (Correct answer)
- Nail down the cupped shingles flat before overlaying
- Apply roofing cement to the cupped areas and proceed with overlay
Correct answer: Tear off the existing layer before installing new shingles
Cupped shingles indicate moisture issues and will telegraph through new shingles, shortening their life; tear-off is required for a proper installation.
Question 2: A GAF Certified contractor inspects a 3-year-old roof with shingle blow-offs. The installation records show 4-nail patterns were used in a high-wind zone rated for 6 nails. What warranty consequence applies?
- The manufacturer covers the blow-offs under the standard limited warranty
- The warranty is voided because the installation did not follow GAF's high-wind nailing requirements (Correct answer)
- Only a prorated partial warranty applies based on years in service
- The contractor's general liability policy covers it without warranty impact
Correct answer: The warranty is voided because the installation did not follow GAF's high-wind nailing requirements
GAF's warranty requires adherence to published installation specifications, including high-wind nailing; non-compliance voids the warranty.
Question 3: During reroofing, a contractor discovers the roof decking has a 1/2-inch gap between OSB panels throughout. What action should be taken before laying underlayment?
- Proceed since small gaps are within tolerance
- Fill gaps with roofing cement and continue installation
- Install H-clips and ensure panels have proper 1/8-inch spacing, replacing panels if over-spaced (Correct answer)
- Overlay with 1/4-inch plywood before installing underlayment
Correct answer: Install H-clips and ensure panels have proper 1/8-inch spacing, replacing panels if over-spaced
Excessive gaps between deck panels can cause shingle irregularities and void warranties; panels should be repositioned or replaced to achieve proper 1/8-inch spacing with H-clips.
Question 4: A homeowner calls 6 months after installation complaining of interior ceiling stains below a skylight. The contractor installed new flashing per the skylight manufacturer, but not per GAF's flashing guidelines. Who bears responsibility?
- The skylight manufacturer, since their flashing was installed
- The roofing contractor, for not following GAF's required flashing methods (Correct answer)
- The homeowner, for choosing a non-compatible skylight
- Shared equally between GAF and the skylight manufacturer
Correct answer: The roofing contractor, for not following GAF's required flashing methods
GAF-certified contractors must follow GAF's flashing requirements; using alternate methods that cause leaks places responsibility on the installer.
Question 5: A steep-slope roof (10:12 pitch) requires workers to use fall protection. A subcontractor wants to use only toe boards. What is the OSHA-compliant and best-practice approach?
- Toe boards alone are sufficient on slopes above 8:12
- Personal fall arrest systems or a safety net system are required on roofs above 6:12 (Correct answer)
- Toe boards plus warning lines are acceptable above 8:12
- No fall protection is required since workers are experienced
Correct answer: Personal fall arrest systems or a safety net system are required on roofs above 6:12
OSHA requires personal fall arrest systems, safety nets, or guardrail systems on steep-slope roofs above 6:12; toe boards alone do not meet this standard.
Question 6: A flat roof section over a garage has been leaking at the parapet wall. The previous contractor used standard steep-slope shingles up the parapet. What is the correct repair?
- Extend the shingles higher up the parapet and add more roofing cement
- Remove the shingles, install base flashing and cap flashing at the parapet per low-slope specs (Correct answer)
- Caulk all visible gaps around the shingles at the parapet
- Add a metal cap to the parapet top only
Correct answer: Remove the shingles, install base flashing and cap flashing at the parapet per low-slope specs
Parapet walls on low-slope roofs require base flashing integrated with the membrane and metal cap flashing; steep-slope shingles are not an appropriate flashing material here.
Question 7: A contractor is asked to install a new GAF roof on a home where the attic has open soffits but no ridge vent. The homeowner declines to add a ridge vent. What is the best course of action?
- Proceed and install shingles; ventilation is the homeowner's responsibility
- Refuse the job entirely since ventilation cannot be waived
- Document the homeowner's refusal in writing and note potential warranty limitations before proceeding (Correct answer)
- Install power ventilators on the roof without the homeowner's approval
Correct answer: Document the homeowner's refusal in writing and note potential warranty limitations before proceeding
When a homeowner declines required ventilation improvements, the contractor should document this in writing because inadequate ventilation can void GAF's warranty.
GAF Case Analysis & Practical Application 3
A customer wants to re-roof over an existing layer of 3-tab shingles.
The deck shows no rot, but the existing shingles have cupping.
What is the correct approach per best practices?