CSLB C-39 Roofing (Trade Exam) — All Questions
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55 questions
Which material is named in CSLB's definition of the C-39 Roofing classification?
- a.Structural steel
- b.Urethane foam✓
- c.Gypsum drywall
- d.Ceramic floor tile
CSLB's C-39 definition lists roofing materials including urethane foam, metal roofing systems, shakes, shingles, tile and slate. Structural steel, drywall and floor tile belong to other classifications.Cal. Code Regs. tit. 16 §832.39 (C-39 classification)
What is the minimum slope for building-integrated photovoltaic (BIPV) roof panels applied directly to the roof deck?
- a.1/4:12
- b.1:12
- c.4:12
- d.2:12✓
The CRC allows BIPV roof panels only on slopes of 2 units vertical in 12 horizontal or greater. One-quarter inch per foot is the minimum for membrane systems, not BIPV.2025 CRC R905.16.2
A homeowner wants a new covering on a 3:12 roof. Which covering is NOT permitted at that slope?
- a.Metal roof shingles
- b.Wood shakes
- c.Slate shingles✓
- d.Asphalt shingles
Slate requires a slope of 4:12 or greater. Wood shakes and metal shingles are allowed from 3:12, and asphalt shingles from 2:12.2025 CRC R905.6.2
Clay tile is proposed for a porch roof with a 2:12 slope. Is it allowed?
- a.Yes, with double underlayment
- b.Yes, if the tile is fastened every row
- c.No; tile needs 2-1/2:12✓
- d.Yes, if the tile is under 9 psf
Clay and concrete tile may be installed only on slopes of 2-1/2:12 or greater. Double underlayment is required from 2-1/2:12 to 4:12, but it cannot make a 2:12 tile roof legal.2025 CRC R905.3.2
Outside fire hazard severity zones, when must the ENTIRE existing roof covering be brought to at least Class C?
- a.When more than 50 percent is replaced within one year✓
- b.When more than 25 percent is replaced within five years
- c.Only when the building is sold
- d.Whenever any repair is made
The CRC requires the entire roof covering to be at least Class C when more than 50 percent of the total roof area is replaced within any one-year period. Any covering applied in a repair must itself be at least Class C.2025 CRC R902.1.2
Which roof assembly does the CBC treat as Class A without a listing?
- a.Untreated wood shakes
- b.Asphalt shingles on plywood
- c.A single-ply membrane on insulation
- d.An exposed concrete roof deck✓
The CBC's Class A exceptions include roof assemblies with coverings of brick, masonry or an exposed concrete roof deck. Shingles, shakes and membranes need a listing to establish their class.2025 CBC 1505.2
In the wildland-urban interface, how are roof assemblies with fire-retardant-treated wood shingles and shakes classified?
- a.As Class A assemblies✓
- b.As nonclassified roofing
- c.As Class B assemblies
- d.As Class C assemblies
The WUI Code requires roof assemblies containing fire-retardant-treated wood shingles and shakes to comply with CBC 1505.6 and be classified as Class A assemblies.2025 CWUIC 503.2.3
A house in Climate Zone 6 is getting a complete new low-sloped roof. What aged solar reflectance must the new roofing product have, if no trade-off is used?
- a.At least 0.10
- b.At least 0.63✓
- c.No requirement in Climate Zone 6
- d.At least 0.20
Low-sloped residential reroofs in Climate Zones 4 and 6 through 15 need an aged solar reflectance of at least 0.63 and thermal emittance of at least 0.75, or SRI 75. The 0.20 value is for steep-sloped roofs.2025 Energy Code 150.2(b)1I
For a steep-slope residential reroof in Climate Zone 9, which is listed as an alternative that counts as equivalent to the cool-roof product requirement?
- a.A thicker felt underlayment
- b.A new ridge vent line
- c.A radiant barrier in the attic✓
- d.A darker shingle color
The Energy Code treats a radiant barrier in the attic (not installed directly above spaced sheathing), R-38 ceiling insulation, no attic ducts in listed zones, or R-2 continuous deck insulation as equivalent to the steep-slope reflectance requirement.2025 Energy Code 150.2(b)1I
A nonresidential building has a 2,400 sq ft roof. The owner will replace 1,500 sq ft. Do the Energy Code roof-alteration requirements apply?
- a.Only if it is a hotel or motel
- b.Yes; over half is altered✓
- c.No; only full replacements count
- d.No; under 2,000 sq ft is altered
The trigger is more than 50 percent of the roof or more than 2,000 sq ft, whichever is less. Half of 2,400 sq ft is 1,200 sq ft, which is the lesser figure, and 1,500 sq ft exceeds it.2025 Energy Code 141.0(b)2B
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Under the Energy Code, how is a roof with a slope of 1-1/2:12 classified?
- a.Steep-sloped
- b.Low-sloped✓
- c.Flat roof exempt from rules
- d.Mansard
The Energy Code defines a low-sloped roof as one with a rise-to-run ratio less than 2:12 and a steep-sloped roof as 2:12 or greater.2025 Energy Code 100.1 definitions
Besides C-39 Roofing, which classification does CSLB list as unable to submit a workers' compensation exemption?
- a.C-20 Warm-Air HVAC✓
- b.C-54 Ceramic and Mosaic Tile
- c.C-27 Landscaping
- d.C-33 Painting
CSLB lists C-8 Concrete, C-20 Warm-Air HVAC, C-22 Asbestos Abatement, C-39 Roofing and C-61/D-49 Tree Service as unable to submit an exemption.CSLB Issuing My License
How much credit toward the four-year experience requirement can a Certificate of Completion of Apprenticeship in roofing provide?
- a.Up to four years
- b.Up to one year
- c.None at all
- d.Up to three years✓
CSLB may grant up to three years of credit for an accredited apprenticeship certificate in the classification, but at least one year must be practical experience.CSLB Experience for Exam
A building is 45 x 28 ft in plan including overhangs, with a uniform 5:12 roof. How many squares of roof surface are there before waste?
- a.13.65 squares✓
- b.15.00 squares
- c.12.60 squares
- d.11.70 squares
The plan area is 1,260 sq ft and the 5:12 slope factor is 13/12, or about 1.083, so the roof surface is 1,365 sq ft, or 13.65 squares. 12.60 squares omits the slope factor.Roofing math
A roof covers 1,600 sq ft of plan area at a uniform 9:12 slope. What is its true surface area?
- a.2,262 sq ft
- b.1,923 sq ft
- c.2,000 sq ft✓
- d.1,600 sq ft
At 9:12 the slope factor is the square root of (144 + 81) divided by 12, which is 15/12 = 1.25. 1,600 x 1.25 = 2,000 sq ft.Roofing math
What is a 6:12 roof slope expressed as a percentage?
- a.60 percent
- b.50 percent✓
- c.25 percent
- d.6 percent
Percent slope is rise divided by run: 6 divided by 12 is 0.5, or 50 percent. The CRC writes 3:12 as 25-percent slope by the same arithmetic.2025 CRC slope notation
A roof needs 96 lineal feet of drip edge. Pieces are 10 ft long and every joint takes the code minimum lap. How many pieces are needed?
- a.10 pieces✓
- b.9 pieces
- c.8 pieces
- d.11 pieces
Drip edge segments must overlap at least 2 inches, so each 10-ft piece covers 9 ft 10 in. 96 divided by 9.833 is 9.8, which rounds up to 10 pieces.2025 CRC R905.2.8.5
A roof is 22 squares before waste. With 10 percent waste and shingles packaged 3 bundles per square, how many bundles should be ordered?
- a.66 bundles
- b.70 bundles
- c.76 bundles
- d.73 bundles✓
22 squares plus 10 percent is 24.2 squares; 24.2 x 3 = 72.6 bundles, rounded up to 73. Sixty-six bundles leaves out the waste allowance.Roofing math
An attic is 1,200 sq ft and does not meet the conditions for a reduced ventilation ratio. What minimum net free ventilating area is required?
- a.1,152 sq in✓
- b.2,400 sq in
- c.576 sq in
- d.1,200 sq in
The default ratio is 1/150: 1,200 divided by 150 is 8 sq ft, and 8 x 144 = 1,152 sq in. The 576 sq in figure is the 1/300 ratio, which needs the exception's conditions.2025 CRC R806.2
A rectangular hip roof with equal slopes on all sides measures 30 x 50 ft including overhangs. How long is the ridge?
- a.30 ft
- b.50 ft
- c.20 ft✓
- d.25 ft
For an equal-slope rectangular hip roof, the ridge is the length minus the width: 50 - 30 = 20 ft. A gable roof's ridge would run the full 50 ft.Roofing math
A four-person crew installs 10 squares per 8-hour day. How many labor hours does a 35-square job take?
- a.28 hours
- b.112 hours✓
- c.140 hours
- d.80 hours
The job takes 35 / 10 = 3.5 days, and 4 workers x 8 hours x 3.5 days = 112 labor hours. Twenty-eight hours counts days but not workers.Roofing math
A job's cost is $14,000. What selling price gives a 30 percent margin on price?
- a.$19,600
- b.$18,200
- c.$16,800
- d.$20,000✓
For a 30 percent margin, cost is 70 percent of price: $14,000 / 0.70 = $20,000. Adding 30 percent to cost ($18,200) is a markup that yields only about a 23 percent margin.Roofing math
In the CBC, a Class A roof assembly is one that is effective against which level of fire-test exposure?
- a.Moderate exposure
- b.Severe exposure✓
- c.Exposure to windborne embers
- d.Light exposure
The CBC describes Class A assemblies as effective against severe fire test exposure. Moderate exposure describes Class B, light exposure describes Class C, and the classes are not defined by embers alone.2025 CBC 1505.2
On a new house, the edge of the roof deck will sit 2 feet from the lot line. What roof classification rule does CRC R902.1 apply?
- a.No classification, since it is a house
- b.A noncombustible deck is required
- c.At least Class C is required✓
- d.Class A is required at that distance
R902.1 requires a minimum Class A, B or C roofing where the roof deck edge is less than 3 feet from a lot line. Residential use does not waive it, the code does not force Class A for every such roof, and a noncombustible deck alone does not satisfy a classification rule.2025 CRC R902.1
Where a Class A, B or C roof assembly is required, which test methods does the CRC name?
- a.ASTM E108 or UL 790✓
- b.ASTM C1167 or ASTM C1492
- c.ASTM D3161 or ASTM D7158
- d.UL 2703 or UL 7103
Fire classification is established by ASTM E108 or UL 790. D3161 and D7158 are wind tests for shingles, C1167 and C1492 are tile product standards, and UL 2703 and UL 7103 cover photovoltaic systems.2025 CRC R902.1
Under the 2025 WUI code, a reroofer replaces only one slope of an existing house in a wildland-urban interface area. What fire class must the portion applied meet?
- a.No class, since under half is replaced
- b.At least Class C
- c.At least Class B
- d.At least Class A✓
In the WUI code, all portions of a roof covering applied during an addition, alteration or repair must meet at least Class A. Class B and Class C are lower than the WUI floor, and the one-half replacement trigger does not excuse a repair portion.2025 CWUIC 507
A roof construction weighs 26 lb/ft2 and is part of a residential reroof. How does the Energy Code treat its reflectance and emittance minimums?
- a.It must meet the low-slope values
- b.It must meet them with a white coating
- c.It need not meet them✓
- d.It must meet them in cool climates
Roof constructions weighing at least 25 lb/ft2 are not required to meet the aged solar reflectance, thermal emittance or SRI minimums. Neither the low-slope values, a climate condition nor a white coating is imposed on such heavy roofs.2025 Energy Code 150.2(b)1Ii, Exception 3
In the 2025 CRC, a roof is in a Fire Hazard Severity Zone. Which additional code does R902.1.1 say its roofing must comply with?
- a.Part 9, the Fire Code for high-hazard areas
- b.Part 7, the Wildland-Urban Interface Code✓
- c.Part 2, the Building Code for fire-rated roofs
- d.Part 6, the Energy Code for roof reflectance
Roofing in Fire Hazard Severity Zones or WUI areas must also comply with Part 7, the California Wildland-Urban Interface Code. Parts 9, 2 and 6 are the Fire, Building and Energy Codes, which do not carry the WUI roofing rules.2025 CRC R902.1.1
A lapped, nonsoldered-seam metal roof will use applied lap sealant. What minimum slope does the CRC allow?
- a.2:12
- b.3:12
- c.1/2:12✓
- d.1/4:12
With applied lap sealant, lapped metal roofs need at least 1/2:12. 1/4:12 is the standing-seam minimum, and 3:12 is the minimum when no lap sealant is applied. 2:12 is not a figure the metal-panel section sets.2025 CRC R905.10.2
Mineral-surfaced roll roofing must conform to which standards under the CRC?
- a.ASTM C1167 or C1492, Grade 1
- b.ASTM D3909 or D6380, Class M✓
- c.ASTM D226 or D4869, Type II
- d.ASTM D3462 or D7158, Class H
Mineral-surfaced roll roofing shall conform to ASTM D3909 or ASTM D6380, Class M. D3462 and D7158 are asphalt shingle standards, D226 and D4869 are underlayments, and C1167 and C1492 are tile standards.2025 CRC R905.5.4
Solar panels will be racked over an existing roof covering. Which listing must the system carry?
- a.UL 2703✓
- b.ASTM D3462
- c.ASTM E1592
- d.UL 7103
Photovoltaic panel systems mounted on top of a roof must be listed and labeled to UL 2703. UL 7103 is for BIPV shingles that are the roof covering, D3462 is an asphalt shingle standard, and E1592 is a metal panel wind test.2025 CRC R907.4
A building-integrated photovoltaic system will serve as the roof covering. Which standard governs its fire classification test, listing and label?
- a.ASTM D7158
- b.UL 2703
- c.UL 790
- d.UL 7103✓
BIPV systems installed as the roof covering are tested, listed and labeled for fire classification to UL 7103. UL 2703 is for panels mounted over a covering, UL 790 is the general roof assembly test, and D7158 is a shingle wind standard.2025 CRC R902.3
Roofing is delivered in bulk shipments instead of marked packages. What must accompany them under the CRC?
- a.A contractor's signed receipt confirming the load was delivered
- b.A copy of the roofing permit posted for the job address
- c.Manufacturer marks and test-agency labels on a bill of lading✓
- d.A safety data sheet attached to each pallet of material
Bulk shipments must carry the same identifying marks and testing agency label information as packages, issued as a certificate or on a bill of lading. A receipt, a permit copy and a safety data sheet do not identify the product or its listing.2025 CRC R904.4
A 40 x 24 ft building plan, overhangs included, has a gable roof at 6:12 with equal slopes. About how many squares of roof surface?
- a.11.5 squares
- b.21.5 squares
- c.10.7 squares✓
- d.9.6 squares
Plan area is 960 sq ft. The 6:12 slope factor is about 1.118, so surface area is about 1,073 sq ft, or 10.7 squares. 9.6 squares forgets the slope factor, 11.5 uses the 8:12 factor, and 21.5 mistakenly doubles the area.Roofing math
A plan note gives the roof as a 50-percent slope. What is that expressed as rise in 12 inches of run?
- a.6:12✓
- b.4:12
- c.5:12
- d.8:12
Percent slope is rise divided by run times 100, so 50 percent is 6 in 12. 5:12 is about 42 percent, 4:12 is about 33 percent, and 8:12 is about 67 percent.2025 CRC slope notation
A rafter spans a run of 14 ft with a total rise of 7 ft. What is its length along the slope, to the nearest tenth of a foot?
- a.21.0 ft
- b.14.0 ft
- c.12.1 ft
- d.15.7 ft✓
Rafter length is the square root of 14 squared plus 7 squared, about 15.65 ft, which rounds to 15.7 ft. 21.0 ft adds run and rise, 14.0 ft ignores the rise, and 12.1 ft subtracts instead of adding the squares.Roofing math
Two equal 8:12 roof planes meet in a valley that runs 9 ft along each plan side. How long is the valley measured on the roof, to the nearest tenth?
- a.9.0 ft
- b.18.0 ft
- c.14.1 ft✓
- d.12.7 ft
Each plan side is 9 ft and the rise over that run is 6 ft, so valley length is the square root of 81 + 81 + 36, about 14.1 ft. 12.7 ft is the plan diagonal without rise, 9.0 ft is one side only, and 18.0 ft adds the two sides.Roofing math
Laminated shingles come 4 bundles to the square. An estimator figures 28 net squares and adds 8 percent for waste. How many bundles go on the order?
- a.112 bundles
- b.84 bundles
- c.91 bundles
- d.121 bundles✓
28 squares with 8 percent waste is 30.24 squares; at 4 bundles per square that is 120.96, which rounds up to 121 bundles. 112 omits the waste, 84 omits the waste and uses 3 bundles per square, and 91 uses 3 bundles per square.Roofing math
A roof has a 36-ft ridge and four hips of 17 ft each. One bundle of cap shingles covers 30 lineal feet. How many bundles are needed?
- a.5 bundles
- b.2 bundles
- c.3 bundles
- d.4 bundles✓
The total is 36 + 68 = 104 lineal feet. 104 divided by 30 is 3.47, and bundles cannot be split, so 4 are needed. 3 bundles falls short, 2 counts the ridge only, and 5 is more than the arithmetic requires.Roofing math
Underlayment for a 2,300 sq ft surface at 6:12 goes on in a single layer with 2-inch laps. Each 36-in-wide roll is 144 ft long. How many rolls?
- a.6 rolls✓
- b.5 rolls
- c.7 rolls
- d.8 rolls
With a 2-inch lap each roll shows 34 inches, so net coverage is 408 sq ft. 2,300 divided by 408 is 5.64, which rounds up to 6 rolls. 5 rolls rounds 5.6 down and leaves part of the roof bare, while 7 and 8 add waste allowances the problem did not ask for.2025 CRC R905.1.1
On a 3:12 roof, full-width sheets of underlayment overlap half a sheet plus 2 inches. A 36-in-wide, 144-ft roll covers how much roof, ignoring the starter strip?
- a.192 sq ft✓
- b.408 sq ft
- c.432 sq ft
- d.216 sq ft
The lap is 18 + 2 = 20 inches, leaving 16 inches of exposure, so 144 ft x 16/12 = 192 sq ft. 216 uses only a half-width lap, 408 uses the single-layer 2-inch lap, and 432 ignores laps entirely.2025 CRC R905.1.1
A crew of three roofers each lay 6 squares per day. Counting only whole days, how long does a 63-square reroof take?
- a.4 days✓
- b.5 days
- c.3 days
- d.11 days
The crew installs 18 squares a day, so 63 squares is 3.5 days, which is billed as 4 full days. 3 days stops short of the work, 5 days adds an unneeded day, and 11 days divides by one roofer's rate with no crew multiplication.Roofing math
Direct cost of a reroof is $18,000 and the bid is set at cost plus 25 percent. What share of the bid price is gross profit?
- a.20 percent✓
- b.80 percent
- c.30 percent
- d.25 percent
A 25 percent markup gives a price of $22,500 and a $4,500 profit, which is 20 percent of the price. 25 percent confuses markup with margin, 80 percent is the cost share of the price, and 30 percent is a markup, not the margin this price yields.Roofing math
A 30-square roof has two layers of shingles to tear off, each layer weighing 220 lb per square. How many tons of debris result?
- a.13.2 tons
- b.66 tons
- c.3.3 tons
- d.6.6 tons✓
Two layers of 30 squares at 220 lb is 13,200 lb, and dividing by 2,000 lb per ton gives 6.6 tons. 3.3 tons counts only one layer, 13.2 tons treats a ton as 1,000 lb, and 66 tons shifts the decimal.Roofing math
Tile on a 24-square roof runs 90 pieces per square. With a 5 percent breakage allowance, how many tiles should be ordered?
- a.2,160 tiles
- b.2,520 tiles
- c.2,268 tiles✓
- d.2,052 tiles
24 x 90 = 2,160, and 5 percent more gives 2,268. 2,160 leaves out the breakage allowance, 2,052 subtracts it instead of adding it, and 2,520 uses 100 pieces per square.Roofing math
Concrete tile weighs 880 pounds per square, installed. What is that in pounds per square foot?
- a.0.88 lb/ft2
- b.9.8 lb/ft2
- c.8.8 lb/ft2✓
- d.88 lb/ft2
A square is 100 sq ft, so 880 lb divided by 100 is 8.8 lb/ft2, which is below the 9 psf line the CRC uses for tile fastening. 88 and 0.88 misplace the decimal, and 9.8 adds an arbitrary pound.2025 CRC R905.3.8
How many 4 x 8 ft insulation boards does a two-layer, staggered job need on a 50 x 36 ft deck, with 5 percent waste?
- a.113 boards
- b.60 boards
- c.119 boards✓
- d.57 boards
One layer is 1,800/32 = 56.25 boards, two layers is 112.5, and 5 percent waste gives 118.1, rounded up to 119. 113 omits waste, 60 is one layer with waste, and 57 is one layer without waste.Roofing math
Felt rolls cover 2 squares net after laps. How many rolls does a 38-square roof need if it is built with four plies and no waste is added?
- a.76 rolls✓
- b.19 rolls
- c.38 rolls
- d.152 rolls
Four plies on 38 squares is 152 squares of felt, and at 2 squares per roll that is 76 rolls. 19 rolls counts a single ply, 38 rolls counts only two plies, and 152 treats each roll as 1 square.Roofing math
A 30 x 60 ft attic meets both conditions for reduced venting. What total net free area does the 1/300 ratio require?
- a.12 sq ft
- b.6 sq in
- c.864 sq in✓
- d.1,728 sq in
1,800 divided by 300 is 6 sq ft, and 6 x 144 is 864 sq in. 1,728 sq in uses the 1/150 ratio, 6 sq in drops the conversion factor, and 12 sq ft is the 1/150 area in square feet.2025 CRC R806.2
A 2,000 sq ft attic uses the 1/300 ratio. How much of the required net free area must be at upper ventilators?
- a.384 to 480 sq in✓
- b.192 to 240 sq in
- c.480 to 960 sq in
- d.576 to 720 sq in
Total required is 2,000/300 x 144 = 960 sq in. The upper portion must be 40 to 50 percent, which is 384 to 480 sq in. 576 to 720 uses 60 to 75 percent, 192 to 240 uses 20 to 25 percent, and 480 to 960 uses half to all of the total.2025 CRC R806.2