InterNACHI Roofing Systems and Components 4 — Questions and Answers
Question 1: What is the correct installation sequence for drip edge at the rake (gable) edge of a roof?
- Drip edge installed over the underlayment (Correct answer)
- Drip edge installed under the underlayment
- Drip edge installed with no underlayment required at rakes
- Drip edge is not required at rake edges
Correct answer: Drip edge installed over the underlayment
At rake edges, drip edge is installed over the underlayment so water is directed away from the fascia and off the roof edge correctly.
Question 2: A home inspector observes that a flat roof has significant ponding water 48 hours after rainfall. What is the concern?
- Ponding is expected and not a deficiency on flat roofs
- Ponding can accelerate membrane deterioration and indicates inadequate drainage (Correct answer)
- Ponding only becomes a deficiency if it exceeds 2 inches in depth
- Ponding indicates the roof was recently re-coated
Correct answer: Ponding can accelerate membrane deterioration and indicates inadequate drainage
Ponding water that remains 48 hours after rainfall accelerates membrane degradation and indicates poor slope or blocked drainage, both of which are reportable deficiencies.
Question 3: Which roofing material requires the installation of a solid or spaced wood deck for proper performance?
- EPDM membrane
- Built-up roofing (BUR)
- Wood shingles and shakes (Correct answer)
- Modified bitumen
Correct answer: Wood shingles and shakes
Wood shingles and shakes require either solid or spaced sheathing to allow airflow beneath them for drying and to prevent moisture-related decay.
Question 4: When inspecting a metal roof, an inspector notices white, powdery deposits near fasteners. What does this indicate?
- Galvanic corrosion from dissimilar metals in contact (Correct answer)
- Normal oxidation of the metal surface coating
- Efflorescence from the underlying concrete deck
- Condensation freeze-thaw cycling under the panels
Correct answer: Galvanic corrosion from dissimilar metals in contact
White powdery deposits near fasteners typically indicate galvanic corrosion, which occurs when dissimilar metals are in contact in the presence of moisture.
Question 5: What is the minimum headlap required for standard 3-tab asphalt shingles?
- 1 inch
- 2 inches (Correct answer)
- 4 inches
- 6 inches
Correct answer: 2 inches
Standard 3-tab asphalt shingles require a minimum headlap of 2 inches to provide adequate weather protection at the overlapping joint.
Question 6: Which type of ventilation system works on the principle of convection to move air through an attic?
- Power attic ventilator (PAV)
- Ridge-and-soffit ventilation (Correct answer)
- Gable-end fans
- Turbine vents with electric assist
Correct answer: Ridge-and-soffit ventilation
Ridge-and-soffit ventilation is a passive system that relies on convection (stack effect): cool air enters at the soffit and warm air escapes at the ridge.
Question 7: What condition is described when an asphalt shingle's tabs curl downward while the bond strip area remains flat?
- Cupping
- Blistering
- Clawing (Correct answer)
- Fishmouthing
Correct answer: Clawing
Clawing occurs when shingle tabs curl downward while the upper portion stays flat, typically caused by moisture imbalance or improper ventilation.
InterNACHI Roofing Systems and Components 4
What is the correct installation sequence for drip edge at the rake (gable) edge of a roof?