CSLB C-39 Roofing (Trade Exam) — All Questions
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65 questions
Which coating designation does the CRC table list for 55-percent aluminum-zinc-alloy-coated steel roof panels?
- a.ASTM A653 G90
- b.ASTM B370
- c.ASTM B209
- d.ASTM A792 AZ 50✓
The table lists 55 percent aluminum-zinc-alloy-coated steel under ASTM A792 AZ 50. A653 G90 is the zinc-coated galvanized designation, B209 is aluminum, and B370 is copper.2025 CRC Table R905.10.3(2)
Structural standing seam metal panel roof systems must be tested for wind resistance under which standards?
- a.UL 2703 or UL 7103
- b.ASTM E1592 or FM 4474✓
- c.ASTM D3161 or D7158
- d.ASTM C1492 or C1167
Structural standing seam systems are tested to ASTM E1592 or FM 4474. D3161 and D7158 are shingle tests, C1492 and C1167 are tile standards, and UL 2703 and UL 7103 are photovoltaic standards.2025 CRC R905.10.5
Why does the NPS say mastic or sealant is not a viable repair for damaged slates?
- a.It adds too much weight to the roof structure overall
- b.It stains the slate surface permanently within a year
- c.It eventually hardens and cracks, letting water in✓
- d.It cannot be applied below 60 degrees in cool weather
The NPS says mastic and sealants are effective at first but will eventually harden and crack, allowing water to enter. Staining, weight and temperature are not the reasons it gives.NPS Preservation Brief 29
According to the NPS, when are repairs to a slate roof usually less economical than replacing the roof?
- a.When the ridge needs to be repointed with mortar
- b.When 20 percent or more of the slates are failed✓
- c.When a single slate on the roof is cracked
- d.When the roof has been in service over 30 years
If 20 percent or more of the slates on a roof or slope are broken, cracked, missing or sliding, replacement is usually less expensive than individual repairs. One cracked slate, age alone or ridge work does not meet that threshold.NPS Preservation Brief 29
How does the NPS say a damaged slate is first removed?
- a.Pry it up with a long flat pry bar
- b.Burn out its nails with a propane torch
- c.Break it out in pieces with a hammer
- d.Cut or pull its nails with a ripper✓
The damaged slate is removed by cutting or pulling out its nails with a ripper. Prying and hammering break the neighboring slates, and a torch can damage the underlayment and structure.NPS Preservation Brief 29
How does the NPS say a replacement slate is secured?
- a.A wooden wedge driven under, covered by a loose shingle
- b.One nail in the joint above, hidden by a copper strip✓
- c.Adhesive on the back, then covered by a bead of sealant
- d.Two nails at the top corners, covered over by mastic
The new slate is held by one nail through the vertical joint in the course above, and a copper piece with friction fit is slid up over the nail. Two face nails, adhesive and wedges are not the method described.NPS Preservation Brief 29
Storm damage has opened part of a slate roof. What does the NPS advise doing right away?
- a.Paint the exposed area with sealant
- b.Install a temporary covering immediately✓
- c.Wait for dry weather and then inspect
- d.Remove the slates on the slope
The NPS says a temporary roof covering should be installed immediately after the storm to prevent more water damage to the interior. Waiting, sealing and stripping the slope either allow damage or create more.NPS Preservation Brief 29
How tightly should slate nails be driven, according to the NPS?
- a.Not tight, unlike asphalt and wood shingles✓
- b.Tight, driven flush with the slate surface
- c.Hard, until the head bites into the slate
- d.Slightly proud, with the head above the slate
Slate nails should not be driven tight, as is the case with asphalt and wood shingles. Nails driven too far crack the slate, and projecting nails puncture the slate above.NPS Preservation Brief 29
How can a roofer move across a tile roof to fix broken tiles without more damage, per the NPS?
- a.Walk along the ridge tiles of the roof
- b.Walk along the eave line, tile to tile
- c.Spread weight with plywood, planks or sandbags✓
- d.Wear hard-soled boots and step lightly and quickly
The NPS says plywood sheets, planks or burlap bags filled with sand distribute weight so the roofer can move without additional breakage. Ridge, boots and eave paths still concentrate load on the tile.NPS Preservation Brief 30
How does the NPS describe securing a replacement clay tile after the broken one is removed?
- a.Two nails through the face of the new tile
- b.Mastic spread under the new tile and edges
- c.A stainless wire tie to the batten above it
- d.A copper tab nailed below, bent up over the tile✓
A tab of double-thickness copper stripping is nailed to the sheathing below, the new tile is slipped in, and the strip is bent up over the tile. Face nails would crack it, and mastic and wire ties are not what the NPS describes.NPS Preservation Brief 30
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What causes galvanic corrosion on a roof, according to the NPS?
- a.Oil residue on new metal
- b.Overdriven nails in asphalt shingles
- c.Standing water on bare wood
- d.Dissimilar metals in direct contact✓
The NPS says galvanic action occurs when dissimilar metals, such as copper and iron, are in direct contact, for example steel nails in copper sheet. The other causes are not galvanic.NPS Preservation Brief 4
How does the NPS say galvanic corrosion can sometimes be prevented between dissimilar roofing metals?
- a.Wrap them in building paper
- b.Press them tightly together
- c.Insert a plastic insulator between them✓
- d.Paint both metals with aluminum paint
In some cases the corrosion is prevented by inserting a plastic insulator between the dissimilar materials. Paint, tight contact and paper do not isolate the metals reliably.NPS Preservation Brief 4
A contractor suggests coating existing asphalt shingles to make them cool. What does the DOE note?
- a.It adds a Class A fire rating to the shingles
- b.It may void the manufacturer's warranty✓
- c.It is required for roofs in hot climate zones
- d.It is a standard field step on most shingle roofs
The DOE says asphalt shingles are not typically coated in the field and doing so may void the manufacturer's warranty. It is not a standard step, it does not add a fire rating, and it is not required.DOE Guidelines for Selecting Cool Roofs
A new covering over wood shingles or shakes creates a combustible concealed space. What must cover the old surface?
- a.Two layers of roofing felt, nailed down securely
- b.Nothing, if the concealed space is vented to the outside air
- c.Gypsum board, mineral or glass fiber, or other accepted material✓
- d.Plywood sheathing nailed over the old shakes
The entire existing surface must be covered with gypsum board, mineral fiber, glass fiber or other accepted materials securely fastened in place. Felt and plywood are combustible, and venting does not remove the requirement.2025 CRC R908.4.1
For which existing roof covering does the CRC bar installing a recover roof?
- a.Slate, clay or cement tile✓
- b.One layer of asphalt shingles
- c.A standing-seam metal roof
- d.A built-up roof in good condition
A recover is not permitted where the existing covering is slate, clay or cement tile (or asbestos-cement tile). A single shingle layer, a standing-seam roof and a sound built-up roof are not listed as barring a recover.2025 CRC R908.4