Roof Sailing Knowledge 3 — Questions and Answers
Question 1: What material is most commonly used for step flashing where a roof meets a vertical sidewall?
- Copper or galvanized steel (Correct answer)
- PVC sheeting
- Asphalt roll roofing
- Rubberized caulk alone
Correct answer: Copper or galvanized steel
Step flashing is cut from copper or galvanized steel and interwoven with each shingle course to redirect water away from the wall junction.
Question 2: What is the minimum recommended headlap for standard three-tab asphalt shingles?
- 1 inch
- 2 inches
- 3 inches (Correct answer)
- 6 inches
Correct answer: 3 inches
A minimum 2-inch headlap (often defaulting to a standard 3-inch exposure system) is recommended to prevent water infiltration between courses.
Question 3: Which condition makes a roof deck unsuitable for direct shingle application without repair?
- Deck boards with minor surface weathering
- Deck boards with gaps larger than 1/4 inch (Correct answer)
- Deck with a pitch above 6:12
- Deck painted with exterior-grade primer
Correct answer: Deck boards with gaps larger than 1/4 inch
Gaps larger than 1/4 inch between deck boards can cause shingles to crack or lose fastener hold, requiring repairs or a new overlay panel.
Question 4: In roofing, what does 'one square' of material cover?
- 10 square feet
- 50 square feet
- 100 square feet (Correct answer)
- 144 square feet
Correct answer: 100 square feet
One roofing square equals 100 square feet of roof surface, the standard unit used to calculate material quantities.
Question 5: What is the function of a cricket or saddle behind a chimney?
- To anchor the chimney cap to the flue
- To divert water around the chimney and prevent pooling (Correct answer)
- To support the weight of the chimney on the deck
- To seal the gap between flashing and mortar
Correct answer: To divert water around the chimney and prevent pooling
A cricket is a small peaked structure built behind a chimney to redirect water flow and prevent debris accumulation at that intersection.
Question 6: Which tool is used to measure the slope of a roof from the ground or eave?
- Chalk line
- Magnetic pitch gauge (Correct answer)
- Roofing hatchet
- Pry bar
Correct answer: Magnetic pitch gauge
A magnetic pitch gauge is placed on a rake or rafter and reads the slope directly, allowing measurement without climbing to the peak.
Question 7: When a roofer refers to 'starter shingles,' what is their purpose?
- They serve as a visible decorative bottom border
- They seal the tabs of the first full shingle course against wind and water (Correct answer)
- They provide extra thickness to the eave edge
- They replace the need for a drip edge
Correct answer: They seal the tabs of the first full shingle course against wind and water
Starter shingles are placed along the eave before the first full course and provide the sealant strip that bonds the first course tabs, preventing wind uplift.
Roof Sailing Knowledge 3
What material is most commonly used for step flashing where a roof meets a vertical sidewall?