CSLB C-39 Roofing (Trade Exam) — All Questions
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250 questions
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
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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
A 1,200 sq ft attic uses the 1/300 ratio, and half the area goes at the ridge. A ridge vent offers 18 sq in of net free area per foot. What length is needed?
- a.24 ft
- b.32 ft
- c.16 ft✓
- d.8 ft
Total required is 4 sq ft or 576 sq in, half is 288 sq in, and 288 divided by 18 is 16 ft. 32 ft uses the whole 576 sq in, 8 ft takes only a quarter of it, and 24 ft assumes a 12 sq in per foot product.2025 CRC R806.2
Three roof planes have plan areas of 900 sq ft at 4:12, 450 sq ft at 6:12 and 300 sq ft at 9:12. About how many squares of surface?
- a.18.3 squares✓
- b.16.5 squares
- c.18.8 squares
- d.20.6 squares
Each plane is multiplied by its own slope factor (about 1.054, 1.118 and 1.250), giving about 1,827 sq ft or 18.3 squares. 16.5 squares uses plan area alone, 20.6 applies the steepest factor to everything, and 18.8 averages the three factors without weighting by area.Roofing math
A single 20.5 ft valley is lined with 10-ft pieces of flashing, each end lap 4 inches. How many pieces are needed?
- a.3 pieces✓
- b.2 pieces
- c.4 pieces
- d.5 pieces
The first piece covers 10 ft and each added piece adds 9 ft 8 in after the 4-inch end lap, so two pieces reach 19 ft 8 in, which is short of 20.5 ft, and three reach 29 ft 4 in. Two pieces leave the valley uncovered, and four or five add whole pieces the length does not call for.2025 CRC R905.3.9
A hip roof face is a trapezoid with a 36-ft eave, a 16-ft ridge side and a 12-ft slant height. What is its area?
- a.312 sq ft✓
- b.192 sq ft
- c.624 sq ft
- d.432 sq ft
Trapezoid area is the average of the parallel sides times the height, (36 + 16)/2 x 12 = 312 sq ft. 432 uses the eave length alone, 192 uses the ridge side alone, and 624 forgets to halve the sum.Roofing math
A roofer holds a level 48 inches out horizontally from the roof surface and measures 16 inches of rise to the roof. What is the slope?
- a.4:12✓
- b.5:12
- c.16:12
- d.3:12
16 inches of rise over 48 inches of run is the same as 4 inches over 12. 3:12 would show 12 inches of rise, 5:12 would show 20 inches, and 16:12 reports the measured rise without scaling the run to 12.2025 CRC slope notation
What is the minimum clearance the Fire Code sets between an asphalt kettle and combustible material or a building opening?
- a.50 feet
- b.5 feet
- c.10 feet
- d.20 feet✓
Kettles stay at least 20 feet from combustible material, combustible building surfaces and building openings, inside a controlled area marked by cones or barriers. 10 feet is the distance for fuel containers from the burner, and 5 and 50 feet are not figures in this section.2025 CFC 303.2
To shorten the hose run, a roofer wants the kettle parked on the commercial roof deck. What does the Fire Code say?
- a.Kettles are not allowed on the roof✓
- b.It is allowed with a fire watch posted
- c.It is allowed if attended
- d.It is allowed on a noncombustible deck
Asphalt kettles and pots shall not be used inside or on the roof of a building. Attendance, a noncombustible deck and a fire watch are conditions found elsewhere in the rules, but none of them overrides this prohibition.2025 CFC 303.2
What extinguisher rating must be within 25 feet of an asphalt kettle while it is in use under the Fire Code?
- a.At least 3-A
- b.At least 20-B:C
- c.At least 40-B:C✓
- d.At least 2-A:10-B:C
The Fire Code requires an extinguisher with a minimum 40-B:C rating within 25 feet of each kettle in use, plus a separate multipurpose unit on the roof. 2-A:10-B:C and 20-B:C are too small for this rule, and 3-A alone has no flammable-liquid rating.2025 CFC 303.5
How must waste materials from a roofing job be removed, under CBC 3301.5?
- a.By burning them on site in a steel barrel each day
- b.By dropping them in a pile beside the wall for pickup
- c.So they do not injure persons or damage adjacent property✓
- d.By sweeping them into the street gutter each evening
Waste must be removed in a manner that prevents injury or damage to persons, adjacent properties and public rights-of-way. Piling, burning and sweeping into the street all create hazards.2025 CBC 3301.5
Where must roofing materials and equipment NOT be placed on a job next to a public road?
- a.Within 10 feet of a neighbor's fence
- b.Within 15 feet of a utility pole
- c.Within 30 feet of a driveway
- d.Within 20 feet of a street intersection✓
The code bars storage that obstructs hydrants, standpipes, alarm boxes, catch basins or manholes, and bars storage within 20 feet of a street intersection. The fence, driveway and utility-pole distances are not part of that rule.2025 CBC 3308.1.1
Before a reroof, what must the structural roof components be capable of supporting?
- a.The weight of the crew standing on the deck
- b.The dead weight of the finished covering itself
- c.The new covering plus material and equipment loads✓
- d.The weight of the existing covering being replaced
R908.2 requires the structure to carry the covering system and the material and equipment loads during installation. The finished covering alone, the old covering alone, or the crew alone each leave out part of the load.2025 CRC R908.2
A low-slope roof has an existing scupper that serves as its required secondary drainage. The roof is being replaced. What is the rule?
- a.Keep it if the roof membrane is a white one
- b.Keep it unless a code-compliant overflow system replaces it✓
- c.Remove it and seal the parapet wall opening shut with sealant
- d.Replace it with a single primary roof drain
Existing secondary drainage required by the code shall not be removed unless replaced by secondary drains or scuppers designed to Section 1502.2. Sealing the parapet would trap water, membrane color is unrelated, and a primary drain does not provide emergency overflow.2025 CBC 1512.1
A roof is not sloped to drain over its edges. Where does CRC R903.4 require roof drains?
- a.At each corner of the building
- b.Along the ridge line
- c.At the center of the roof
- d.At each low point of the roof✓
Unless the roof drains over its edges, drains go at every low point where water would collect. The center, the corners and the ridge are not selected by where water pools.2025 CRC R903.4
How tall must the opening of an overflow scupper through a parapet be, at minimum?
- a.6 inches
- b.8 inches
- c.2 inches
- d.4 inches✓
Overflow scuppers must be three times the size of the roof drains with a minimum opening height of 4 inches, and their inlet sits 2 inches above the low point. 2 inches is the inlet elevation, not the opening height; 6 and 8 inches are not set by the section.2025 CRC R903.4.1
During a reroof, an existing roof vent flange and edging are rusted. What does the CRC require?
- a.Prime and reuse them
- b.Replace them✓
- c.Cover them with mastic
- d.Reuse them if they are sealed
Existing flashings, edgings, outlets and vents that are rusted, damaged or deteriorated shall be replaced. Priming, mastic and sealing do not restore a corroded component.2025 CRC R908.5
Before bitumen is applied to sheet-metal flashing, what step does the CRC require?
- a.Leave it bare for best bonding
- b.Sand it before installation
- c.Prime it before installation✓
- d.Coat it with aluminized emulsion
Metal flashing to which bituminous materials are to be adhered shall be primed before installation. Sanding, aluminized emulsion and bare metal do not meet that requirement.2025 CRC R908.6
A roof leaks, and the owner wants a reflective coating applied. According to the DOE, what comes first?
- a.Apply ordinary exterior paint as a primer
- b.Apply the coating thick enough to bridge them
- c.Wait for the next rain to find them
- d.Repair the leaks and membrane problems✓
The DOE guidance says any leaks or problems with the membrane must be repaired before the roof is coated. A thick coating hides rather than cures defects, waiting does not repair, and ordinary paints are not designed to last on roofs.DOE Guidelines for Selecting Cool Roofs
A clay tile roof is leaking. According to the NPS, what must happen before repairs are made to the sheathing, felt or structural members?
- a.Identify the source and cause of the leak✓
- b.Remove the felt and underlayment from the deck
- c.Coat the entire roof with a thick sealant layer
- d.Replace the tiles on the leaking slope at once
The NPS says repairs to structural members, sheathing, felt or roofing paper follow once the source and cause of the leak are identified. Replacing every tile, sealing the roof or stripping the underlayment would not locate the cause.NPS Preservation Brief 30
Which condition prevents a roof recover (a new covering over the old) under the CRC?
- a.The deck is dry and sound
- b.The new covering follows manufacturer instructions
- c.The existing covering is one layer of shingles
- d.The roof already has two or more coverings✓
A recover is not allowed where the existing roof already has two or more applications of any covering. One existing layer, a dry sound deck and manufacturer-instructed installation are conditions that permit a recover.2025 CRC R908.4
When asbestos-containing roofing is removed, how must the material be taken off the roof wherever feasible?
- a.Pulverized with a power broom
- b.In an intact state✓
- c.Broken into small pieces
- d.Pried off with sudden force
Section 1529 requires roofing material to be removed in an intact state to the extent feasible, which limits dust. Breaking, pulverizing or prying with sudden force all render the material non-intact and release fibers.Cal. Code Regs. tit. 8 §1529
Asbestos-containing roofing will be rendered non-intact during removal. What method is required unless it is infeasible or creates a hazard?
- a.Dry power brushing
- b.Wet methods✓
- c.Compressed-air blowing
- d.Dry sweeping
Wet methods are required for roofing that is not intact or will be made non-intact, unless they are infeasible or create safety hazards. Dry sweeping, compressed air and dry brushing all throw dust into the air.Cal. Code Regs. tit. 8 §1529
Gravel-surfaced built-up roofing containing asbestos felts is being cut with a power cutter. What controls the dust?
- a.Collected by HEPA or HEPA vacuumed at the cut✓
- b.Left in place and covered with loose gravel
- c.Collected with a standard shop vacuum at the cut
- d.Swept dry with a broom along the cut line
For aggregate-surfaced built-up roofs, dust from the cutter must be collected by a HEPA dust collector or HEPA vacuumed along the cut line. Dry sweeping and ordinary vacuums release fibers, and leaving dust in place does not control it.Cal. Code Regs. tit. 8 §1529