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CSLB C-39 Roofing Contractor practice questions

207 free questions with answers and explanations.

Practice test
  1. 51.A skylight curb measures 24 inches by 48 inches. The manufacturer's flashing kit is designed for skylights up to this exact size and includes head, sill, and step flashing pieces sufficient for the entire perimeter of one skylight. If a contractor is installing 5 identical skylights on the same roof, how many flashing kits must be ordered?Estimating and Planning
  2. 52.A contractor estimates a roofing job requires 22 squares of shingles priced at $145 per square, and adds a 10% material waste allowance to the order. What is the total material cost?Estimating and Planning
  3. 53.A property manager wants to protect a newly installed EPDM roof membrane from foot traffic damage near a roof access hatch and rooftop HVAC units. What is the correct practice for walkway pad placement?Low-Slope Roofing
  4. 54.A crew is installing a self-adhered SBS modified bitumen base sheet over a primed concrete deck. What is the primary purpose of applying asphalt primer to the concrete before installing the self-adhered membrane?Low-Slope Roofing
  5. 55.Under California's Title 24 Energy Code, a new low-slope (steep-slope alternative) residential roof covering must meet minimum cool roof requirements. What is the minimum aged solar reflectance typically required for steep-slope residential roofing products under the current standard?Flashing, Ventilation and Insulation
  6. 56.A contractor is insulating an attic ceiling assembly for a home in coastal Southern California (a mild Title 24 climate zone). Regarding vapor barrier installation, which statement best reflects standard California practice?Flashing, Ventilation and Insulation
  7. 57.A client wants a single-ply membrane that reflects sunlight to reduce cooling costs and is typically manufactured in white sheets, unlike EPDM which is almost always black. Which membrane best fits this description?Low-Slope Roofing
  8. 58.A low-slope roof section measuring 36 squares requires double-layer #15 felt underlayment per code. Each roll of #15 felt provides 4 squares of net coverage after overlap. How many rolls of felt are required?Estimating and Planning
  9. 59.A metal roofing contractor is installing a standing seam copper roof system and must account for thermal expansion and contraction. What is the typical spacing for concealed clips along the standing seams?Steep-Slope Roofing
  10. 60.A roofer installs asphalt shingles using 4 nails per shingle, with 80 shingles per square. The roofing nails used run approximately 320 nails per pound, and nails are sold only in 50-pound boxes. For a 24-square roof, how many boxes of nails must be ordered?Estimating and Planning
  11. 61.Starter strip shingle bundles each cover 105 linear feet. The eaves and rakes requiring starter strip total 340 linear feet. Applying a 5% waste allowance, how many bundles are required?Estimating and Planning
  12. 62.A 4-ply BUR system uses 36-inch-wide roofing felt applied by the shingle method with each ply overlapping the previous ply by 75 percent (typical for a 4-ply system). What is the exposed width of each felt ply per course?Low-Slope Roofing
  13. 63.Under California's Title 24 Energy Code, a builder is installing a steep-slope residential roof and wants to meet the prescriptive cool roof requirement using an aged solar reflectance rating. What is the minimum aged solar reflectance value the roofing product must meet?Flashing, Ventilation and Insulation
  14. 64.A roof has three valleys, each measuring 40 linear feet, for a total valley length of 120 linear feet. Valley flashing rolls provide 50 linear feet of net coverage after required overlap. How many rolls must the contractor purchase?Estimating and Planning
  15. 65.A hip roof's flat footprint area is 2,750 square feet with a slope of 9:12. The contractor applies a 15% waste factor for hips, valleys, and cutting. How many squares should be ordered, rounded up to the next whole square?Estimating and Planning
  16. 66.An attic space measures 2,400 square feet and has an approved vapor retarder installed, qualifying it for the 1/300 ventilation ratio with a balanced 50/50 split between intake and exhaust vents. How many square inches of net free area (NFA) must be provided by the exhaust (ridge) vents alone?Estimating and Planning
  17. 67.A foreman is preparing to torch-apply an SBS modified bitumen cap sheet directly over exposed polyisocyanurate insulation with no cover board present. What is the correct concern and course of action?Low-Slope Roofing
  18. 68.A roofer is preparing to install standard concrete roof tile on a new residential structure. Per manufacturer and code standards, what is the minimum roof slope for a standard tile installation without requiring special low-slope modifications such as double underlayment?Steep-Slope Roofing
  19. 69.A general contractor is specifying a new TPO roof covering for a low-slope commercial building in California and must comply with Title 24 cool roof requirements. The minimum aged solar reflectance and thermal emittance values are primarily intended to reduce what?Low-Slope Roofing
  20. 70.A specification requires an elastomeric roof coating to achieve 24 dry mils thickness. The coating has 60% solids by volume. How many wet mils must be applied to achieve the required dry film thickness?Low-Slope Roofing
  21. 71.A technician is preparing to apply an elastomeric roof coating early in the morning on a humid day. Manufacturer specifications require the substrate temperature to remain at least 5°F above the dew point during application and curing. If the current dew point is 58°F, what is the minimum acceptable substrate temperature for coating application?Low-Slope Roofing
  22. 72.A building inspector is checking base flashing on a newly installed low-slope modified bitumen roof where it terminates at a parapet wall. Per standard code requirements, what is the minimum height the base flashing must extend above the finished roof surface?Low-Slope Roofing
  23. 73.A single-story home has an attic floor area of 2,400 square feet. The attic will be vented using the 1/300 ratio with a balanced system (50% intake at the eaves, 50% exhaust at the ridge). How many square inches of net free ventilation area are required at the ridge (exhaust side) alone?Flashing, Ventilation and Insulation
  24. 74.A sheet metal worker is installing edge metal at the perimeter of a low-slope built-up roof, designed to cover the felt plies at the roof edge and direct water away from the fascia. What is this component commonly called?Low-Slope Roofing
  25. 75.A sheet metal worker is installing counterflashing into a masonry parapet wall to cover the top edge of base flashing. To what minimum depth should the reglet (flashing receiver slot) typically be cut into the mortar joint for secure, weathertight anchorage?Low-Slope Roofing
  26. 76.A ventilated attic has a floor area of 2,000 square feet and will use a single powered attic ventilator instead of passive vents. Using the standard sizing guideline of 0.7 CFM per square foot of attic floor area, what minimum fan capacity should the ventilator provide?Flashing, Ventilation and Insulation
  27. 77.A vaulted cathedral ceiling assembly (no attic space) covers 3,600 square feet and will use the 1/150 ratio with vents split equally between the eave and ridge. How many square inches of net free area must be provided at the EAVE intake side?Flashing, Ventilation and Insulation
  28. 78.A roof has 2,400 square feet of deck area requiring new plywood sheathing. The contractor uses standard 4-foot by 8-foot sheets (32 square feet each) and applies a 10% waste factor for cuts and hips. How many sheets should be ordered?Estimating and Planning
  29. 79.A contractor is re-roofing over an existing asphalt-saturated felt substrate and plans to install a new PVC single-ply membrane. To prevent asphalt bleed-through from staining or reacting with the new membrane over time, what should be installed as a separator layer between the old substrate and the new membrane?Low-Slope Roofing
  30. 80.A low-slope roofing estimator is calculating material needs and refers to a single 'square' of roofing area. How many square feet does one roofing square equal?Low-Slope Roofing
  31. 81.A roof's flat plan (footprint) area measures 1,800 square feet, and the roof slope is 8:12. What is the actual roof surface area in squares, rounded to the nearest tenth?Estimating and Planning
  32. 82.A mechanically attached TPO membrane is installed using 10-foot-wide sheets. Manufacturer specifications require fasteners spaced 12 inches on center along each seam only, with no additional fasteners in the field of the sheet. How many fasteners are required per 10 ft × 10 ft square in the field zone?Low-Slope Roofing
  33. 83.A contractor is designing drainage for a newly installed low-slope built-up roof to avoid chronic ponding. What is the minimum slope generally required by code and industry standards for positive drainage?Low-Slope Roofing
  34. 84.A roofing crew is installing a metal expansion joint cover across a building's structural expansion joint on a low-slope roof. Why is the joint cover fabricated with a raised, bellows-shaped profile rather than a flat sheet?Low-Slope Roofing
  35. 85.A roof slope length from eave to ridge measures 26 feet. Underlayment rolls are 36 inches wide and installed horizontally with a 4-inch overlap between courses, leaving 32 inches (2.67 feet) of effective exposure per course. How many courses are needed to cover the full slope length?Estimating and Planning
  36. 86.A rectangular building measures 24 feet by 36 feet. The roof has a 4:12 slope and 12-inch overhangs on all four sides. What is the approximate total roof surface area including overhangs, in squares (rounded to the nearest tenth)?Estimating and Planning
  37. 87.A roof rises 6 inches over a horizontal run of 24 inches. Expressed as a standard roof pitch (rise per 12 inches of run), what is the slope?Estimating and Planning
  38. 88.A general contractor is selecting a mechanically attached TPO membrane for a warehouse roof with anticipated heavy rooftop foot traffic and equipment servicing. Which membrane thickness would provide the best long-term puncture and wear resistance compared to a thinner alternative?Low-Slope Roofing
  39. 89.A roof has a 12-inch eave overhang and a 6-inch-thick exterior wall. Code requires the ice barrier to extend to a point at least 24 inches inside the interior wall face. The roof slope is 6:12. What is the minimum length of ice and water shield required, measured along the roof slope from the eave edge, rounded to the nearest tenth of a foot?Estimating and Planning
  40. 90.A client's roof requires 21 squares of standard three-tab asphalt shingles. Each bundle covers 33.3 square feet, meaning three bundles equal one square. How many bundles must be ordered for the entire job?Estimating and Planning
  41. 91.An attic has no vapor barrier installed and the contractor wants to avoid the more restrictive ventilation ratio. Under California building code provisions, which ventilation ratio applies to attics WITHOUT a vapor barrier?Flashing, Ventilation and Insulation
  42. 92.During tear-off of an old built-up roof, a laborer uses a long-handled steel tool with a flat, angled blade to pry up and scrape away layers of felt and gravel from the deck. What is this tool called?Low-Slope Roofing
  43. 93.A contractor calculates that an attic space requires a total net free ventilation area (NFA) of 432 square inches. The static roof vents specified for the job each provide 50 square inches of net free area. What is the minimum number of static vents required to meet the ventilation requirement?Estimating and Planning
  44. 94.A crew is installing a gravel-surfaced BUR system on a 3,000 sq ft roof section. The flood coat of asphalt is applied at 60 lb per square, and gravel is embedded at a rate of 400 lb per square. How many total pounds of gravel are required for the section?Low-Slope Roofing
  45. 95.To ensure positive drainage at a roof drain, a contractor installs a sump (depression) in the tapered insulation around the drain bowl. The surrounding field insulation is 2 inches thick, and the drain bowl must sit flush with insulation that is recessed 1/2 inch below the surrounding field surface. What insulation thickness should be installed directly at the drain?Low-Slope Roofing
  46. 96.A roof deck requires new plywood sheathing over 3,200 square feet. Standard sheets measure 4 feet by 8 feet (32 square feet each), and the contractor adds a 10% waste factor for cutting and irregular deck shapes. How many sheets of plywood should be ordered?Estimating and Planning
  47. 97.After hot-air welding TPO membrane seams, a quality control technician wants to verify the seam is fully fused. Which field test is the standard method for checking seam integrity?Low-Slope Roofing
  48. 98.A roof section drains toward a single low point but currently ponds water after rainfall because the existing slope is only 1/8 inch per foot over a 24-foot run to the drain, while code minimum is 1/4 inch per foot. How much additional total rise (in inches) must tapered insulation add at the high point to meet minimum code slope over that run?Low-Slope Roofing
  49. 99.A chimney measures 48 inches wide, measured perpendicular to the roof slope, and sits on a roof with a 6:12 slope. A cricket (saddle) must be built behind the chimney to divert water, with its peak height calculated as half the chimney width multiplied by the roof's rise-to-run ratio. What height should the cricket peak be built to?Estimating and Planning
  50. 100.A single-story home has an attic floor area of 3,000 square feet. The contractor will use the 1/300 ventilation ratio with a balanced system split evenly between soffit intake and ridge exhaust vents. How many square inches of net free area must the soffit vents alone provide?Flashing, Ventilation and Insulation