CSLB C-39 Roofing (Trade Exam) — All Questions

Intact asbestos-containing roofing has been removed and is waiting on the roof. By when must it be lowered to the ground?

• a.By the end of the work week in which it is removed
• b.Within seven days after the material is removed
• c.After the entire roof job is finished and cleaned
• d.As soon as practicable, and by the end of the shift✓

Intact asbestos-containing material must be lowered as soon as practicable and in any event no later than the end of the work shift. Seven days, the end of the week or the end of the job all leave debris on the roof too long.Cal. Code Regs. tit. 8 §1529

Non-intact asbestos-containing roofing must stay on the roof for a time. What are the allowed ways to hold it?

• a.Piled by the roof edge under a weighted tarp until pickup
• b.Stacked loose and covered with roofing felt scraps
• c.Left dry on the roof so it stays light to lift
• d.Kept wet, bagged impermeably, or wrapped in plastic✓

While it stays on the roof, non-intact material must be kept wet, placed in an impermeable waste bag, or wrapped in plastic sheeting. Loose stacks, dry piles and tarps do not contain fibers.Cal. Code Regs. tit. 8 §1529

During a reroof, existing clay tiles are removed for reinstallation. Which of them may NOT be reinstalled?

• a.Tiles from the lowest course
• b.Tiles with moss on them
• c.Tiles that are cracked or broken✓
• d.Tiles with faded color

Existing slate, clay or cement tile may be reinstalled, but damaged, cracked or broken pieces may not. Color fade, position on the roof and moss are not damage under the rule.2025 CRC R908.5

Under the CBC, where is flashing required?

• a.At penetrations that are over 12 inches wide
• b.Along the outside roof edges and the eaves
• c.At walls, gutters, slope changes and roof openings✓
• d.On the windward side of the roof in high wind

CBC 1503.2.1 calls for flashing at wall and roof intersections, at gutters, wherever the slope or direction changes, and around roof openings. Limiting it to edges, large penetrations or the windward side leaves leak paths open.2025 CBC 1503.2.1

What must the top surface of a parapet wall provide under the CBC?

• a.A level seat for coping stones
• b.A sealant joint along its length
• c.Positive drainage✓
• d.A raised crown at the center

The top of a parapet wall must provide positive drainage so water does not pond or enter the wall. A level seat would hold water, a crown is not required, and a sealant joint alone does not drain the surface.2025 CBC 1503.3

The CBC says intake and exhaust vents for attics are provided according to Section 1202.2 and which other source?

• a.The vent product manufacturer's instructions✓
• b.The roof covering warranty terms
• c.The owner's utility bill history
• d.The flashing manufacturer's color chart

Vents must follow Section 1202.2 and the vent product manufacturer's installation instructions. A covering warranty, a color chart or utility history is not an installation requirement for vents.2025 CBC 1503.4

Gutters that secure the perimeter edge of a low-slope membrane must be tested to which methods?

• a.RE-1, RE-2 and RE-3 of ES-1
• b.ASTM E108 and UL 790
• c.G-1 and G-2 of SPRI GT-1✓
• d.ASTM D3746 and D4272

Gutters used to secure the membrane perimeter are tested under methods G-1 and G-2 of SPRI GT-1. RE-1 through RE-3 of ES-1 are for other metal edge systems, E108 and UL 790 are fire tests, and D3746 and D4272 are impact tests.2025 CBC 1504.6.1

The CBC says flashing must stop water from entering the wall and roof through which of these?

• a.Gaps beside nailed ridge caps and along the hips
• b.Holes drilled for tie-downs and fasteners
• c.Joints in copings and moisture-permeable materials✓
• d.Seams between insulation boards in the assembly

Flashing is to prevent water entry through joints in copings, through moisture-permeable materials and at intersections with parapet walls and other penetrations. Ridge caps, tie-down holes and insulation seams are not the situations that section names.2025 CBC 1503.2

Which type of low-slope roof must have parapets complying with CBC Table 1504.8?

• a.Roofs with a white membrane
• b.Aggregate-surfaced roofs✓
• c.Roofs with standing seams
• d.Roofs with a vegetated cover

Parapets are required for aggregate-surfaced roofs so loose stone does not wash or blow off the edge. Membrane color, standing seams and vegetation are not the trigger in that section.2025 CBC 1504.8

Ballasted low-slope single-ply roofs must be designed in accordance with which standard?

• a.ANSI/SPRI RP-4✓
• b.FM 4474
• c.SPRI GT-1
• d.ANSI/SPRI ES-1

Ballasted single-ply systems follow ANSI/SPRI RP-4. ES-1 covers metal edge systems, GT-1 covers gutters, and FM 4474 is a wind-uplift test for membrane coverings.2025 CBC 1504.5

Above-deck thermal insulation under a roof covering must comply with which pair of standards?

• a.ASTM C1289 or ASTM C728
• b.NFPA 276 or UL 1256✓
• c.FM 4474 or UL 580
• d.ASTM E108 or UL 790

Above-deck insulation must be covered with a roof covering and comply with NFPA 276 or UL 1256 as an assembly. C1289 and C728 are insulation material standards, E108 and UL 790 are roof fire classification tests, and FM 4474 and UL 580 are uplift tests.2025 CRC R906.1

Gutters and leaders on the outside of a Type I commercial building must be made of what, under the CBC?

• a.Aluminum or copper sheet metal in standard gauges
• b.Galvanized steel sheet metal in standard gauges
• c.Noncombustible, or at least Schedule 40 plastic pipe✓
• d.Sheet material of the owner's choice

Outside gutters and leaders must be noncombustible or not less than Schedule 40 plastic pipe, except for Group R-3, private garages and Type V buildings. Material is not limited to one metal or left to any sheet product.2025 CBC 1502.3

TPO single-ply membrane falls under which ASTM standard in the CBC table?

• a.ASTM D4637
• b.ASTM D6878✓
• c.ASTM D4434
• d.ASTM D6162

TPO membrane is listed under ASTM D6878. D4637 is EPDM, D4434 is PVC, and D6162 is a modified bitumen sheet standard.2025 CBC Table 1507.12.2

Which ASTM standard does the CBC table list for aggregate surfacing on a built-up roof?

• a.ASTM D2178
• b.ASTM D448
• c.ASTM D4601
• d.ASTM D1863✓

Aggregate surfacing for built-up roofs is listed under ASTM D1863. D448 covers ballast stone for single-ply roofs, D2178 is glass felt, and D4601 is the glass fiber base sheet.2025 CBC Table 1507.10.2

Besides the base sheets in Section 1507.11.2, which standards may a base sheet meet when used with a modified bitumen cap sheet?

• a.ASTM D1970 or D4601✓
• b.ASTM D448 or D7655
• c.ASTM D3909 or D6083
• d.ASTM D226 or D1863

The CBC permits a base sheet complying with ASTM D1970 or D4601 under a modified bitumen cap sheet. D3909 is a mineral-surfaced cap sheet and D6083 an acrylic coating, D226 is organic felt and D1863 aggregate, and D448 and D7655 are ballast stone.2025 CBC 1507.11.2.1

Asphalt glass felt for a built-up roof is assigned to which standard in the CBC table?

• a.ASTM D2178✓
• b.ASTM D4601
• c.ASTM D226
• d.ASTM D1863

Asphalt glass felt is listed under ASTM D2178. D226 is asphalt-saturated organic felt, D4601 is the asphalt-coated glass fiber base sheet, and D1863 is aggregate surfacing.2025 CBC Table 1507.10.2

Why does a spray polyurethane foam roof rely on a protective coating, according to the DOE?

• a.Foam is susceptible to mechanical, moisture and UV damage✓
• b.The foam cannot be made watertight without a top layer
• c.The foam shrinks and loses thickness if left uncoated in sun
• d.The foam becomes fire rated when it is coated

The DOE explains that foams are highly susceptible to mechanical, moisture and UV damage, so they depend on a protective coating. The other reasons are not what the DOE gives.DOE Guidelines for Selecting Cool Roofs

What does the DOE call a built-up roof that is surfaced with a modified bitumen sheet?

• a.A ballasted roof
• b.A hybrid roof✓
• c.A flood-coat roof
• d.A protected membrane roof

The DOE says a modified bitumen sheet can be used to surface a built-up roof and calls the result a hybrid roof. A ballasted roof is held down with stone, a flood-coat roof is surfaced with embedded gravel, and a protected membrane roof places insulation above the membrane.DOE Guidelines for Selecting Cool Roofs

The DOE lists three ways a single-ply sheet may be secured to a roof. Which set is correct?

• a.Mechanical fasteners, adhesives, or ballast✓
• b.Torch welding, hot mopping, or nailing on a deck
• c.Solvent welding, bead sealant, or sand fill
• d.Battens, hold-down clips, or standing seams

Single-ply sheets are rolled out and attached with mechanical fasteners, adhered with chemical adhesives, or held down with ballast. Torching and hot mopping belong to bituminous systems, and battens, clips and seams belong to metal panels.DOE Guidelines for Selecting Cool Roofs

A roof coating is to be installed. In addition to the CRC coating section, how must it be installed?

• a.Per the roofer's usual practice on similar jobs
• b.Per the owner's preferred coating thickness
• c.Per the manufacturer's installation instructions✓
• d.Per the method used on the neighboring roof

The CRC says roof coatings shall be installed in accordance with the manufacturer's installation instructions. Usual practice, a neighbor's method or an owner preference does not replace them.2025 CRC R909.1

An applied roof coating must still comply with which other CRC sections?

• a.R902 for fire and R904 for materials✓
• b.R1001 for chimneys and R1003 for hearths
• c.R703 for walls and R806 for venting
• d.R301 for loads and R302 for fire separation

The CRC says roof coating installation shall comply with Section R902, Section R904 and the coating section itself. The other pairs deal with loads, walls, venting or chimneys, not roof classification or materials.2025 CRC R909.1

Which ASTM standard does the CRC list for silicone roof coatings?

• a.ASTM D6083
• b.ASTM D3468
• c.ASTM D6947
• d.ASTM D6694✓

Silicone coating is listed under ASTM D6694. D6083 covers acrylic coatings, D6947 covers moisture-cured polyurethane, and D3468 covers liquid-applied roofing.2025 CRC R909.2

A homeowner wants to brush leftover house paint over a worn membrane. What does the DOE say?

• a.Ordinary paints are not designed to last on roofs✓
• b.Paint is acceptable if it is a white acrylic
• c.Paint is acceptable over a single-ply membrane
• d.Paint is acceptable in a dry, mild climate zone

The DOE says roof coatings are not the same as exterior paints, because ordinary paints are not designed to last on roofs or to protect them. Color, substrate and climate do not change that.DOE Guidelines for Selecting Cool Roofs

The DOE describes one coating type as water based and easy to handle. Which type is it?

• a.Acrylic✓
• b.Silicone
• c.Coal-tar pitch
• d.Aluminized asphaltic emulsion

The DOE lists acrylic coatings as water based and easy to handle with good adhesion. Silicone is described as solvent based and typically used on spray foam, and the emulsion and pitch are different materials.DOE Guidelines for Selecting Cool Roofs

Which product gives a glossy finish on some roofs but falls short of cool-roof standards on low slopes, per the DOE?

• a.Solvent-based silicone coating
• b.A white reflective TPO membrane
• c.Water-based acrylic coating
• d.Aluminized asphaltic emulsion✓

The DOE says aluminized asphaltic emulsions give a glossy finish but fall short of cool roof standards on low-sloped roofs. Acrylic, white TPO and silicone are products it treats as able to be reflective.DOE Guidelines for Selecting Cool Roofs

A membrane is to be adhered with chemical adhesive in cool weather. What does the DOE say about the membrane?

• a.It bonds best when it is cooled below ambient air
• b.It must reach and hold a minimum temperature✓
• c.It needs a primer coating before it is adhered
• d.It needs ballast stone over the wet adhesive

Membranes attached with chemical adhesives must reach and maintain a minimum temperature to bond properly. Chilling it, adding ballast or pre-coating does not address that.DOE Guidelines for Selecting Cool Roofs

How do the DOE guidelines say SPF roofs are kept up over time?

• a.Periodic re-coating with a reflective coating✓
• b.Painting them with ordinary exterior house paint
• c.Stripping off the coating completely each season
• d.Replacing the foam layer every year

SPF roofs are typically coated and periodically re-coated with reflective coatings to protect the foam from UV and water damage. Yearly foam replacement, seasonal stripping and house paint are not described.DOE Guidelines for Selecting Cool Roofs

A commercial low-slope roof with positive drainage is being recovered, and its actual slope is under 1/4:12. Must the slope be raised?

• a.Yes; unless the new roof coating is reflective white
• b.No; slope rules do not apply to existing roofs
• c.Yes; 1/4:12 is mandatory for a reroof
• d.No; this exception covers roofs that already shed water✓

Roof replacement or recover of low-slope coverings need not meet the 1/4:12 minimum where the roof has positive drainage. The minimum is not mandatory for every reroof, coating color is irrelevant, and the rule is an exception rather than a blanket exemption.2025 CBC 1512.1

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