CSLB C-39 Roofing (Trade Exam) — All Questions
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65 questions
What is the minimum number of fasteners for an individual (non-strip) asphalt shingle?
- a.Two✓
- b.Four
- c.One
- d.Six
The CRC requires at least the manufacturer's number of fasteners, but not less than four per strip shingle or two per individual shingle.2025 CRC R905.2.6
What minimum head diameter must an asphalt shingle roofing nail have?
- a.3/8 inch✓
- b.5/16 inch
- c.1/2 inch
- d.1/4 inch
Asphalt shingle nails need a minimum 3/8-inch-diameter head and a 12-gage shank. The 5/16-inch head is the tile nail minimum.2025 CRC R905.2.5
What minimum shank size must an asphalt shingle roofing nail have?
- a.12-gage✓
- b.18-gage
- c.14-gage
- d.16-gage
Asphalt shingle fasteners need at least a 12-gage [0.105 inch] shank. The 11-gage figure is the minimum for tile nails.2025 CRC R905.2.5
To which standard must asphalt shingles comply under the CRC?
- a.ASTM D226
- b.ASTM C406
- c.ASTM D3462✓
- d.ASTM D3909
Asphalt shingles comply with ASTM D3462. D226 is felt underlayment, D3909 mineral-surfaced roll roofing and C406 slate.2025 CRC R905.2.4
Concrete tile is installed at 3:12. What underlayment application is required?
- a.Double underlayment✓
- b.A single layer lapped 2 inches
- c.Self-adhered membrane at the eaves only
- d.No underlayment
For tile slopes from 2-1/2:12 to 4:12, double underlayment application is required. A single layer lapped 2 inches is the method at 4:12 and steeper.2025 CRC R905.3.2
In an area designated for ice barriers, which building does NOT need one?
- a.A two-story house
- b.A house with a 12:12 roof
- c.A detached unheated shed✓
- d.A heated garage attached to a house
The ice barrier requirement has an exception for detached accessory structures not containing conditioned floor area.2025 CRC R905.1.2 exception
Step flashing is installed where shingles meet a wall covered with lap siding. Where does the flashing's vertical leg go?
- a.On top of the siding, sealed
- b.Behind the sheathing
- c.Cut off at the siding's bottom edge
- d.Continuous under the siding✓
Where siding is provided on the vertical sidewall, the vertical leg of the sidewall flashing must be continuous under the siding.2025 CRC R905.2.8.3
What is the minimum thickness of corrosion-resistant metal cap flashing on an asphalt shingle roof?
- a.0.032 inch
- b.0.019 inch✓
- c.0.010 inch
- d.0.0125 inch
Cap flashing must be corrosion-resistant metal of minimum nominal 0.019-inch thickness, the same minimum as metal base flashing.2025 CRC R905.2.8.1
When must valley linings be installed on an asphalt shingle roof?
- a.After the shingles, as a cover
- b.Before the shingles✓
- c.Only on slopes below 4:12
- d.Only when the valley is closed
Valley linings shall be installed in accordance with the manufacturer's instructions before applying shingles.2025 CRC R905.2.8.2
Which copper valley lining meets the CRC table for asphalt shingle open valleys?
- a.Copper-colored paint on steel
- b.Copper foil tape
- c.16 oz cold-rolled copper✓
- d.8 oz copper sheet
The table lists cold-rolled copper of 0.0216 inch nominal, ASTM B370, 16 oz per square foot (and high-yield copper at 12 oz).2025 CRC Table R905.2.8.2
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What minimum height must the splash diverter rib on clay tile valley flashing have?
- a.2 inches
- b.3/4 inch
- c.1/2 inch
- d.1 inch✓
Tile valley flashing extends at least 11 inches each way and has a splash diverter rib at least 1 inch high. The 3/4-inch rib is the metal roof shingle rule.2025 CRC R905.3.9
What minimum head size must a nail for clay or concrete tile have?
- a.5/16 inch✓
- b.3/8 inch
- c.1/4 inch
- d.1/2 inch
Tile nails must be at least 11-gage with a 5/16-inch head. The 3/8-inch head is the asphalt shingle rule.2025 CRC R905.3.7
Concrete tile is installed in an area subject to snow. How many fasteners per tile are required at minimum?
- a.One
- b.One on every other row
- c.None below 5:12
- d.Two✓
In areas subject to snow, not less than two fasteners per tile are required.2025 CRC R905.3.8
Concrete tile is laid on solid sheathing without battens at 3:12 (no snow, no wind design, tile over 9 psf). How are field tiles fastened?
- a.Two fasteners per tile
- b.One fastener per tile✓
- c.No fasteners needed below 5:12
- d.One fastener every other row
On solid sheathing without battens, the table requires one fastener per tile at all slopes. The no-fastener entry below 5:12 applies to spaced sheathing or solid sheathing with battens.2025 CRC Table R905.3.8
Which ASTM standard must roofing slate meet under the CRC?
- a.ASTM C1167
- b.ASTM D3462
- c.ASTM C1492
- d.ASTM C406✓
Slate shingles comply with ASTM C406. C1167 is clay tile, C1492 concrete tile and D3462 asphalt shingles.2025 CRC R905.6.4
What minimum metal does the CRC require for slate valley and flashing metal?
- a.Any painted steel
- b.0.0179-inch G90 steel✓
- c.0.0125-inch G60 steel
- d.0.010-inch aluminum
Slate valley and flashing metal must be a minimum uncoated thickness of 0.0179 inch, zinc-coated G90, and valley flashing at least 15 inches wide.2025 CRC R905.6.7
Slate is installed on a very steep 22:12 mansard. What minimum headlap does the table require?
- a.6 inches
- b.3 inches
- c.2 inches✓
- d.4 inches
At slopes of 20:12 and steeper the minimum slate headlap is 2 inches; 3 inches applies from 8:12 to below 20:12 and 4 inches from 4:12 to below 8:12.2025 CRC Table R905.6.6
Which rule applies to joints in wood shingle courses?
- a.Only the starter course has a joint rule
- b.Joints must line up every other course
- c.No joints aligned in any three adjacent courses✓
- d.Joints may align if they are sealed
Wood shingles are laid with a side lap of at least 1-1/2 inches between joints in courses, and no two joints may be in direct alignment in any three adjacent courses.2025 CRC R905.7.6
Which nail does the table specify for 24-inch wood shingles?
- a.4d box nails✓
- b.3d box nails
- c.8d common nails
- d.6d box nails
The table specifies 3d box nails for 16- and 18-inch shingles and 4d box nails (1-1/2 in x 0.076) for 24-inch shingles.2025 CRC Table R905.7.6(2)
What is the minimum felt used as interlayment strips between courses of wood shakes?
- a.18-inch strips of No. 30 felt✓
- b.12-inch strips of No. 15 felt
- c.Self-adhered membrane strips
- d.36-inch strips of house wrap
Shakes are interlaid with 18-inch-wide strips of not less than No. 30 felt, positioned so the felt is not exposed to the weather.2025 CRC R905.8.8
What minimum grade must naturally durable wood shakes meet?
- a.No. 3
- b.No. 1✓
- c.No. 2
- d.Any grade if labeled
The shake material table requires No. 1 grade for wood shakes of naturally durable wood under the Cedar Shake and Shingle Bureau rules.2025 CRC Table R905.8.5
What is the minimum slope for a lapped, nonsoldered-seam metal roof installed without lap sealant?
- a.1/2:12
- b.2:12
- c.3:12✓
- d.1/4:12
Lapped, nonsoldered-seam metal roofs without applied lap sealant need a 3:12 slope; with lap sealant, 1/2:12; standing seam, 1/4:12.2025 CRC R905.10.2
What minimum weight does the CRC table set for cold-rolled copper sheet roofing (not high-yield)?
- a.8 oz per sq ft
- b.16 oz per sq ft✓
- c.20 oz per sq ft
- d.12 oz per sq ft
The metal roof covering table sets ASTM B370 copper at a minimum of 16 oz/sq ft, or 12 oz/sq ft for high-yield copper.2025 CRC Table R905.10.3(1)
Where must required attic ventilation openings open?
- a.Into the garage
- b.Directly outdoors✓
- c.Into the living space
- d.Into a wall cavity
Required ventilation openings must open directly to the outside air and be protected against birds, rodents, snakes and similar creatures.2025 CRC R806.1
How does the NPS clay tile brief describe removing a single broken tile?
- a.Break it out with a hammer from above
- b.Pry up the course above with a crowbar
- c.Leave it and seal the crack
- d.Cut its nails with a ripper or hacksaw blade✓
The NPS says a broken tile should be carefully removed with a slate ripper or hacksaw blade inserted under the tile to cut the nails holding it.NPS Preservation Brief 30
Why does the NPS say slate should be laid with copper or stainless steel nails?
- a.Steel nails crack the slate when driven
- b.Stainless nails need no pre-punched holes
- c.Copper nails are cheaper
- d.Steel nails rust out first✓
The NPS explains that plain steel and galvanized nails usually rust out long before the slate begins to deteriorate, which is a common cause of slate loss.NPS Preservation Brief 29
A shingle roof has a 5:12 slope. How does the CRC say single-layer underlayment is applied?
- a.Two layers, starting with a half-width strip
- b.Butted edge to edge with no lap
- c.Shingle fashion from the eave, lapped 2 inches✓
- d.Run up the slope, lapped 6 inches
At 4:12 or steeper, one layer is applied shingle fashion, parallel to the eave and starting there, with 2-inch laps. Two layers with a half-width strip is the 2:12 to 4:12 method, butted edges leak, and running up the slope reverses the lapping.2025 CRC R905.1.1
Underlayment materials that must meet a listed ASTM standard are delivered to the roof. What must each bear?
- a.A stamp showing the installer's license number
- b.A tag listing the wind zone for the roof's address
- c.A seal from the local building inspector's office
- d.A label indicating compliance with the standard✓
Underlayment required to comply with the listed ASTM standards must bear a label indicating compliance to the standard designation. An installer stamp, a wind zone tag or an inspector's seal does not identify the product's standard.2025 CRC R905.1.1
Mechanically fastened underlayment under asphalt shingles is nailed with caps. What pattern does the CRC table call for?
- a.A 12-inch grid, with 6-inch spacing at laps✓
- b.A 6-inch grid everywhere
- c.Nails along the laps
- d.A 24-inch grid, with 12-inch spacing at laps
Fasteners go in a grid of 12 inches between side laps with 6-inch spacing at side and end laps. A uniform 6-inch grid over-fastens the field, nails only at laps leave the field loose, and 24-inch spacing is too wide.2025 CRC Table R905.1.1(3)
Interlayment used between courses of wood shakes must comply with which standard?
- a.ASTM D3909
- b.ASTM D1970
- c.ASTM D226, Type I✓
- d.ASTM D4869, Type IV
Shake interlayment shall comply with ASTM D226, Type I. D1970 is self-adhering underlayment, which is not used under shakes, D3909 is mineral-surfaced roll roofing, and D4869 is a different underlayment standard.2025 CRC R905.8.4
On a 5:12 roof in an area with a history of ice along eaves, how far must an ice barrier reach inside the exterior wall line?
- a.To the ridge
- b.At least 24 inches✓
- c.At least 6 feet
- d.At least 12 inches
The ice barrier runs from the lowest roof edges to a point not less than 24 inches inside the exterior wall line. 12 inches falls short, and 6 feet or the full slope is more than the section requires.2025 CRC R905.1.2
What may an ice barrier consist of under the CRC?
- a.Two layers of loose-laid sheet metal at the eave edge
- b.A single coat of cold-applied mastic over the deck edge
- c.One layer of felt, lapped 2 inches at the eave
- d.Two cemented underlayment layers, or a self-adhering sheet✓
The ice barrier is at least two layers of underlayment cemented together, or a self-adhering polymer-modified bitumen sheet in place of normal underlayment. A single felt layer, a mastic coat or loose metal does not form that barrier.2025 CRC R905.1.2
Where the eave of a sloped roof meets a vertical sidewall, what does CRC R903.2.1 require?
- a.A continuous sealant bead along the siding
- b.A flashing that diverts water off the wall✓
- c.A wider overhang on the wall-side rafters
- d.A second layer of underlayment at the wall
A flashing must divert water away where the eave meets a sidewall, which is a kickout or diverter. Sealant, an overhang and extra underlayment do not redirect water.2025 CRC R903.2.1
Drip edge on a shingle roof is nailed to the deck. How far apart may the fasteners be, at most?
- a.16 inches on center
- b.6 inches on center
- c.12 inches on center✓
- d.24 inches on center
Drip edges are mechanically fastened to the roof deck at not more than 12 inches on center. 24 and 16 inches are too far apart, and 6 inches is closer than the rule requires.2025 CRC R905.2.8.5
What minimum width applies to one-ply smooth roll roofing lining a covered valley?
- a.36 inches✓
- b.18 inches
- c.12 inches
- d.24 inches
A closed valley lined with one ply of smooth roll roofing needs a width of not less than 36 inches. 24 inches is the metal lining width for an open valley, 18 inches is the bottom layer of a two-ply open lining, and 12 inches is not a code width.2025 CRC R905.2.8.2
Valley flashing under wood shakes must reach how far past the centerline on each side?
- a.At least 15 inches
- b.At least 10 inches
- c.At least 11 inches✓
- d.At least 7 inches
Wood shake valley flashing extends not less than 11 inches from the centerline each way. 7 and 10 inches are wood shingle figures, and 15 inches is the width of slate valley flashing.2025 CRC R905.8.9
Insulation is going into an attic that has eave vents. What clearance must remain at the roof sheathing?
- a.At least a 6-inch space
- b.At least a 1-inch space✓
- c.No space if the insulation is rigid
- d.A 1/4-inch space
R806.3 requires not less than a 1-inch space between the insulation and the roof sheathing and at the vent so air can flow. 6 inches is more than needed, rigid insulation is not exempted, and 1/4 inch is the shake airspace figure.2025 CRC R806.3
An attic uses the 1/300 ventilation exception. Where must the balance of the required ventilation be placed?
- a.In the bottom one-third of the space✓
- b.At the gable ends
- c.Anywhere, with no location rule
- d.In the upper third beside the ridge
After 40 to 50 percent goes at upper ventilators, the balance must be in the bottom one-third of the attic space to set up airflow. Placing it high, only at gables, or anywhere defeats the cross flow.2025 CRC R806.2
An attic in a Climate Zone 6, 7 or 8 area, as the CRC sets climate zones, uses the 1/300 ventilation ratio. What vapor retarder condition applies?
- a.A Class III retarder installed under the roof shingles
- b.Class I or II retarder, warm-in-winter side of ceiling✓
- c.No retarder is needed, since the attic is well vented
- d.A Class I retarder on the roof sheathing underside
In Climate Zones 6, 7 and 8, the 1/300 exception requires a Class I or II vapor retarder on the warm-in-winter side of the ceiling. A Class III retarder, no retarder or a retarder on the sheathing does not meet the condition.2025 CRC R806.2
Asphalt shingle nails must be long enough to penetrate the roofing and reach how far into the sheathing?
- a.Roughly 1 inch
- b.At least 3/4 inch✓
- c.At least 1-1/2 inches
- d.At least 1/4 inch
Nails must penetrate through the roofing materials and not less than 3/4 inch into the sheathing. 1/4 inch is too short to hold, and 1-1/2 inches or roughly 1 inch are not what the section sets.2025 CRC R905.2.5
What is the smallest attaching wire the CRC allows for securing clay or concrete tile?
- a.0.105 inch
- b.0.035 inch
- c.0.083 inch✓
- d.0.120 inch
Attaching wire for clay or concrete tile shall not be smaller than 0.083 inch. 0.035 is a cap thickness, and 0.120 and 0.105 are tile nail and shingle nail shank sizes.2025 CRC R905.3.7
Which ASTM standard must concrete roof tile comply with under the CRC?
- a.ASTM C1492✓
- b.ASTM C1167
- c.ASTM D3462
- d.ASTM C406
Concrete roof tile follows ASTM C1492. C1167 is for clay tile, C406 is for slate, and D3462 is for asphalt shingles.2025 CRC R905.3.5
Tile fastening is stepped up near the perimeter. How far does that zone extend?
- a.The outer two courses of tile along each roof edge
- b.Tiles within 10 feet of the eave or the rake
- c.Three courses, at least 36 inches from edges, hips, ridges✓
- d.A 12-inch band of tile along each edge and ridge
Perimeter fastening areas include three tile courses but not less than 36 inches from either side of hips or ridges and from eaves and rakes. Two courses or a 12-inch band is narrower than the rule, and 10 feet is wider.2025 CRC R905.3.7
Tile with an installed weight under 9 lb/ft2 is used. What is the minimum fastening?
- a.One fastener per tile at any slope✓
- b.Two fasteners per tile throughout the roof
- c.None, if the slope is below 5:12
- d.One fastener on alternate rows
Tiles weighing less than 9 lb/ft2 require not less than one fastener per tile regardless of slope. The no-fastener and every-other-row rules belong to battened tables, and two per tile is the snow-area requirement.2025 CRC R905.3.8
How many fasteners does the CRC require to secure each slate shingle?
- a.One per slate
- b.Four per slate
- c.Two per slate✓
- d.Three per slate
Slate shingles are secured with two fasteners per slate. One fastener allows the slate to twist, and three or four exceed the requirement.2025 CRC R905.6.6
Slate shingles must be tested for wind resistance to which standard?
- a.ASTM E1592
- b.ASTM D3161✓
- c.ASTM C406
- d.ASTM D7158
The CRC says slate shingles shall be tested in accordance with ASTM D3161. C406 is the slate product standard, D7158 is the asphalt shingle wind test, and E1592 is for structural standing seam metal.2025 CRC R905.6.5
Wood shingles are laid over spaced sheathing boards. What minimum nominal board size does the CRC set?
- a.1 x 2
- b.1 x 3
- c.2 x 4
- d.1 x 4✓
Spaced sheathing boards must be not less than 1-inch by 4-inch nominal, spaced on centers equal to the weather exposure so the fasteners land on a board. 1 x 2 and 1 x 3 are too narrow to hold the nails, and 2 x 4 is heavier than the rule requires.2025 CRC R905.7.1
Nails for wood shingles go in 10 miles from saltwater. Which does the CRC require?
- a.Type 316 stainless steel✓
- b.Aluminum
- c.Electro-galvanized steel
- d.Type 304 stainless steel
Fasteners within 15 miles of saltwater coastal areas must be Type 316 stainless steel. Electro-galvanized steel and aluminum are not allowed, and Type 304 is acceptable inland but not within the coastal band.2025 CRC R905.7.6
How far must joints in adjacent courses of wood shakes be offset from one another?
- a.At least 3/8 inch
- b.At least 6 inches
- c.At least 1-1/2 inches✓
- d.At least 3 inches
Wood shakes are laid with a side lap of not less than 1-1/2 inches between joints in adjacent courses. 3/8 inch is part of the spacing range, and 3 and 6 inches exceed the code minimum.2025 CRC R905.8.7
What makes up the starter course along the eaves when shakes are the roof covering?
- a.A single course of full-length 24-inch shakes laid flush
- b.Tripled, with felt strips laid between each of the three layers
- c.A single course, set flush with the fascia board edge
- d.Doubled, bottom layer of 15-, 18- or 24-inch shakes or shingles✓
The starter course at the eaves is doubled, and its bottom layer is 15-, 18- or 24-inch wood shakes or shingles. A single course, or a tripled one, is not what the section describes.2025 CRC R905.8.8