InterNACHI Roofing Systems and Components 2 — Questions and Answers
Question 1: What is the minimum recommended slope for asphalt shingles according to standard installation practices?
- 1:12
- 2:12 (Correct answer)
- 4:12
- 6:12
Correct answer: 2:12
Asphalt shingles require a minimum slope of 2:12 (2 inches of rise per 12 inches of run) for standard installation.
Question 2: Which roof component prevents water from entering at the intersection of a roof plane and a vertical wall?
- Ridge cap
- Drip edge
- Step flashing (Correct answer)
- Valley flashing
Correct answer: Step flashing
Step flashing consists of L-shaped metal pieces installed in courses along with the shingles where a roof meets a vertical wall.
Question 3: A home inspector observes cupping of asphalt shingles. What is the most likely cause?
- Improper ventilation causing heat buildup
- Moisture imbalance causing the shingle edges to curl upward (Correct answer)
- Too many fasteners per shingle
- Shingles installed in cold weather
Correct answer: Moisture imbalance causing the shingle edges to curl upward
Cupping occurs when shingle edges turn upward due to moisture differential between the top and bottom surfaces of the shingle.
Question 4: What condition does 'blistering' on an asphalt shingle roof indicate?
- Hail damage from a recent storm
- Trapped moisture or volatile compounds escaping from the shingle (Correct answer)
- Over-driven fasteners causing buckling
- Algae growth beneath the granule surface
Correct answer: Trapped moisture or volatile compounds escaping from the shingle
Blistering results from trapped moisture or volatile compounds in the asphalt that vaporize and create raised bubbles on the shingle surface.
Question 5: Which type of roof deck material is most susceptible to delamination when exposed to prolonged moisture?
- Solid lumber boards
- OSB (oriented strand board) (Correct answer)
- Plywood
- Steel decking
Correct answer: OSB (oriented strand board)
OSB is more susceptible to delamination and swelling from moisture exposure than plywood or solid lumber due to its composite wood fiber construction.
Question 6: When inspecting a roof, an inspector finds granules accumulating in the gutters. What does this most likely indicate?
- Normal weathering on a new roof
- The shingles are approaching end of useful life (Correct answer)
- Improper attic ventilation
- Ice dam formation
Correct answer: The shingles are approaching end of useful life
Significant granule loss in gutters typically indicates shingles are aging and losing their protective coating, signaling they are near the end of their service life.
Question 7: What is the purpose of a cricket (saddle) installed behind a chimney?
- To provide additional structural support to the chimney
- To divert water around the chimney and prevent ponding (Correct answer)
- To seal the chimney cap against wind-driven rain
- To improve attic ventilation near the chimney
Correct answer: To divert water around the chimney and prevent ponding
A cricket is a peaked saddle structure built behind wide chimneys to redirect water away and prevent it from pooling against the chimney base.
InterNACHI Roofing Systems and Components 2
What is the minimum recommended slope for asphalt shingles according to standard installation practices?