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CSLB C-39 Roofing Contractor practice questions

207 free questions with answers and explanations.

Practice test
  1. 1.A roofing crew is installing an open valley on a composition shingle roof. Per code, what is the minimum overall width of the sheet metal valley flashing (measured across the valley centerline)?Flashing, Ventilation and Insulation
  2. 2.A crew is installing 24-inch wood shakes using a double-coverage application on a roof with a 5:12 slope. What weather exposure should be used?Steep-Slope Roofing
  3. 3.A roof requires drip edge along 180 linear feet of eaves and 140 linear feet of rakes, for a combined edge length of 320 feet. Drip edge stock comes in 10-foot pieces, and the estimator adds a standard 5% waste allowance for laps and cuts. How many pieces of drip edge should be ordered?Estimating and Planning
  4. 4.A common rafter spans a horizontal run of 12 feet with a total rise of 5 feet. Using the Pythagorean theorem, what rafter length should the contractor use for the shingle and sheathing takeoff?Estimating and Planning
  5. 5.A contractor is installing 20-inch slate shingles on a roof with an 8:12 slope, which requires a 3-inch headlap. Using the standard slate exposure formula, what exposure should be used?Steep-Slope Roofing
  6. 6.A concrete tile roof has a slope length of 32 feet from eave to ridge, with battens installed at a 13-inch weather exposure per course. The roof width along the eave is 40 feet, and one continuous batten row runs the full width at each course. How many total linear feet of batten material are required?Estimating and Planning
  7. 7.A rectangular building measures 30 feet wide (eave to eave) and 50 feet long, with a roof slope of 5:12. Using a rafter length factor of 1.083 for a 5:12 slope, what is the total roof surface area (both roof planes combined), in square feet?Estimating and Planning
  8. 8.A roofer is installing a fully adhered EPDM membrane and applies EPDM splice adhesive to both the membrane and flashing surfaces before joining them. Per typical manufacturer instructions, what must the applicator do after coating both surfaces and before pressing them together?Low-Slope Roofing
  9. 9.A crew is fabricating open valley metal flashing for a composition shingle roof in an area requiring corrosion-resistant sheet metal per code. What is the minimum acceptable gauge for galvanized steel valley flashing under standard California building code provisions?Flashing, Ventilation and Insulation
  10. 10.While heating Type III asphalt in a roofing kettle, the foreman closely monitors the temperature to stay well below the material's flash point. Why is exceeding the asphalt's flash point during heating a critical safety concern?Low-Slope Roofing
  11. 11.A mason is coordinating with a roofer to install counter flashing into a raked mortar joint on a brick chimney. What is the typical minimum embedment depth required into the mortar joint for the counter flashing to be considered properly secured?Flashing, Ventilation and Insulation
  12. 12.A technician is detailing a roof transition where a PVC membrane flashing will make direct, permanent contact with an adjacent EPDM membrane. What compatibility issue should the technician be aware of?Low-Slope Roofing
  13. 13.A roofer is installing step flashing where a sloped composition shingle roof meets a vertical sidewall. What is the minimum required vertical leg height of each step flashing piece up the sidewall?Steep-Slope Roofing
  14. 14.A 2-inch diameter primary roof drain is rated by the plumbing code drainage table to handle 6,750 square feet of roof area at a rainfall intensity of 4 inches per hour. If the project's design rainfall intensity is only 2 inches per hour, what is the maximum roof area that single drain can serve?Low-Slope Roofing
  15. 15.A roofing contractor measures a house and finds the total roof surface area (all planes combined) is 2,450 square feet. Rounding up to the nearest whole square with no waste added, how many squares should be listed on the material order?Estimating and Planning
  16. 16.A technician is specifying a PVC single-ply membrane for a re-roof over an existing modified bitumen roof. Why is direct contact between PVC membrane and asphalt-based products typically avoided?Low-Slope Roofing
  17. 17.A hip roof has a flat plan (footprint) area of 2,400 square feet and a slope of 8:12. Using a standard roof area factor table, the area factor for an 8:12 hip roof is 1.20. What is the actual roof surface area, expressed in roofing squares?Estimating and Planning
  18. 18.A contractor is installing closed-cell spray polyurethane foam directly against the underside of the roof sheathing to create a conditioned, unvented attic assembly. According to standard building practice for this assembly type, what is required regarding attic ventilation?Flashing, Ventilation and Insulation
  19. 19.A common rafter runs 14 feet horizontally to the ridge with a rise of 8 feet over that run, and extends an additional 2-foot horizontal overhang beyond the exterior wall (total horizontal run of 16 feet) at the same consistent slope. Using the Pythagorean theorem, what is the total rafter length including the overhang, to the nearest tenth of a foot?Estimating and Planning
  20. 20.A roof-to-sidewall intersection ends where a sloped roof meets a wall and transitions into a gutter. Without a specific flashing detail at this termination point, water running down the wall can be diverted behind the gutter and into the wall assembly. What flashing component is specifically required at this location to prevent that intrusion?Flashing, Ventilation and Insulation
  21. 21.A building owner has a low-slope roof section prone to persistent ponding water that has damaged prior asphalt BUR systems. A roofing consultant recommends a coal tar pitch built-up roof for this area instead of asphalt. What property of coal tar pitch makes it better suited to standing water conditions?Low-Slope Roofing
  22. 22.A gable roof with two valleys has a total roof surface area of 2,600 square feet. To account for additional cutting and waste caused by the valleys, the estimator adds a 15% waste factor. How many roofing squares should be ordered, rounded up to the nearest whole square?Estimating and Planning
  23. 23.A roof valley measures 80 linear feet. Self-adhered membrane rolls are 36 inches wide by 36 feet long, and code requires a minimum 6-inch (0.5-foot) end-lap overlap between consecutive rolls along the valley run. How many rolls are needed to cover this single valley?Estimating and Planning
  24. 24.A design engineer specifies an inverted roof membrane assembly (IRMA) for a low-slope building, in which rigid extruded polystyrene insulation is placed above the waterproofing membrane rather than below it. What additional installation requirement is necessary because of this insulation placement?Low-Slope Roofing
  25. 25.An attic space measures 1,800 square feet and has no vapor retarder installed, requiring a 1:150 ventilation ratio per code. What is the total net free ventilating area (NFA) required for this attic, expressed in square feet?Estimating and Planning
  26. 26.A foreman is heating Type III steep asphalt in a kettle for a BUR application. The kettle thermometer reads well above the equiviscous temperature (EVT) range specified on the asphalt's safety data sheet. What is the primary risk of continuing to apply asphalt at this temperature?Low-Slope Roofing
  27. 27.A roofer uses 4 nails per shingle and installs 80 shingles per square across a 26-square roof. Nails are sold in boxes of 3,600. How many boxes must be purchased to complete the job?Estimating and Planning
  28. 28.A technician is using a hand-held hot-air welder to seam TPO membrane sheets. What nozzle temperature range is typically used as a starting point before fine-tuning for ambient temperature and travel speed?Low-Slope Roofing
  29. 29.In a cold climate application, where should the vapor barrier of a batt insulation assembly be installed relative to the insulation to minimize condensation within the wall or roof cavity?Flashing, Ventilation and Insulation
  30. 30.A foreman is installing an APP (atactic polypropylene) modified bitumen membrane on a low-slope roof. Which installation method is most commonly specified for this type of membrane?Low-Slope Roofing
  31. 31.A synthetic underlayment roll covers 10 squares (1,000 sq ft) net after overlap. The total roof area is 32 squares. Applying the standard 10% waste factor for laps and cuts, how many rolls should be ordered?Estimating and Planning
  32. 32.A technician installs step flashing along a shingle roof/sidewall intersection. Each individual step flashing piece must extend a minimum of how far up the wall and overlap the piece below it by how much?Flashing, Ventilation and Insulation
  33. 33.During a roof drainage inspection, a technician checks the strainer/dome on a primary roof drain. Per the California Plumbing Code, at minimum how many inches must the strainer extend above the roof surface immediately surrounding the drain?Low-Slope Roofing
  34. 34.A roofing contractor is installing tapered insulation to create positive drainage on a low-slope BUR roof. The specified taper is 1/4 inch per foot, sloping from a roof drain at the low point to a high point 40 feet away. If the insulation thickness at the drain is 1.5 inches, what minimum insulation thickness is required at the high point?Low-Slope Roofing
  35. 35.A contractor installs R-19 fiberglass batt insulation (designed for a 6-1/4 inch cavity) into a 2×4 wall cavity that is only 3-1/2 inches deep. What is the most accurate outcome of this installation?Flashing, Ventilation and Insulation
  36. 36.A homeowner asks a contractor to add gable end vents to an attic that already has a continuous ridge vent and soffit vents. Why should the contractor advise against combining gable vents with a ridge vent system?Flashing, Ventilation and Insulation
  37. 37.A ballasted EPDM roof system is being installed in a low wind exposure zone where code requires a minimum ballast rate of 10 lb per square foot. The roof area is 6,000 sq ft. How many tons of ballast are required?Low-Slope Roofing
  38. 38.A standard three-tab asphalt shingle measures 12 inches by 36 inches. What is the standard weather exposure used when installing these shingles on a typical steep-slope roof?Steep-Slope Roofing
  39. 39.Per California Building Code provisions governing asphalt shingle roof underlayment, a double layer of underlayment is required for roof slopes within which range?Estimating and Planning
  40. 40.A hip roof has a ridge line of 36 linear feet and four hips measuring 14 linear feet each. Ridge cap shingle bundles cover 25 linear feet per bundle. Applying a 10% waste factor, how many bundles of ridge cap should be ordered?Estimating and Planning
  41. 41.A sidewall where a roof meets a vertical wall measures 24 feet long. Standard 3-tab shingles are installed with a 5.625-inch weather exposure, and one step flashing piece is required at each course along the wall. How many step flashing pieces are needed?Estimating and Planning
  42. 42.A contractor is installing fully adhered EPDM membrane using bonding adhesive rated to cover 60 square feet per gallon per surface, applied to both the substrate and the underside of the membrane. How many gallons of bonding adhesive are needed for a 3,000 sq ft roof section?Low-Slope Roofing
  43. 43.A roofer is flashing a skylight installed on a composition shingle roof. Which flashing component is installed last, at the top (upslope) edge of the skylight curb, overlapping the roofing material above it?Flashing, Ventilation and Insulation
  44. 44.A hip roof has a common rafter run of 15 feet with a 6:12 slope. Using the standard rafter table hip/valley factor of 16.97 inches of hip length per foot of common rafter run, what is the total hip rafter length?Estimating and Planning
  45. 45.A crew is installing a 4-ply BUR system on a 1,200 square foot roof section, requiring 3 interply asphalt moppings at a rate of 23 pounds per square (100 sq ft). How many total pounds of asphalt are needed for the interply moppings?Low-Slope Roofing
  46. 46.A roof has 14 plumbing vent stack penetrations requiring pipe flashing boots. The estimator adds 10% extra to cover potential damage during installation, and boots are sold in packs of 6. How many packs must be purchased?Estimating and Planning
  47. 47.A two-person roofing crew can install 2.5 squares per hour on a straightforward gable roof. The job totals 32 squares of shingles. Based solely on the installation rate, how many labor hours should the estimator budget to complete the shingle installation?Estimating and Planning
  48. 48.A roofer is installing an open metal valley on an asphalt shingle roof. Per standard practice, what should be done regarding the shingles adjacent to the valley?Steep-Slope Roofing
  49. 49.A roof's flat footprint area is 3,000 square feet, and the roof's slope factor yields a calculated roof surface area of 3,600 square feet (36 squares). Due to numerous hips, valleys, and dormers requiring extensive cutting, the contractor applies an additional 18% waste factor on top of the slope-adjusted area. How many squares should be ordered, rounded up to the nearest whole square?Estimating and Planning
  50. 50.A low-slope built-up roof deck measures 3,200 square feet. Modified bitumen cap sheet rolls provide 100 square feet of net coverage per roll after side and end laps are accounted for. How many rolls are required if no additional waste is added?Estimating and Planning