CSLB C-9 Drywall (Trade Exam) — All Questions
18 questions
On a detail drawn at 1/2 inch = 1 foot, a soffit measures 7-3/4 inches. How long is the soffit?
- a.7-3/4 feet
- b.31 feet
- c.15-1/2 feet✓
- d.3-7/8 feet
At 1/2 inch to the foot each inch of drawing is 2 feet, so 7.75 × 2 = 15.5 feet. Thirty-one feet is the reading at 1/4 inch = 1 foot, 7-3/4 feet ignores the scale, and 3-7/8 feet divides by 2 instead of multiplying.CSLB C-9 study guide 13E-9 (computation questions)
A ceiling 30 feet by 20 feet will be covered with 4 × 10 sheets. With no waste allowance, how many sheets are needed?
- a.13 sheets
- b.20 sheets
- c.19 sheets
- d.15 sheets✓
The ceiling is 600 square feet, and 600 ÷ 40 = 15 sheets. Thirteen sheets is 600 ÷ 48, the count for 4 × 12 sheets; 19 sheets is 600 ÷ 32, the count for 4 × 8 sheets; and 20 sheets has no basis in the area.UFGS 09 29 00 (48-inch board width)
Two bedrooms, each 12 feet by 11 feet with 8-foot ceilings, get board on the walls only. How many square feet of wall board is that, before waste?
- a.1,000 square feet
- b.368 square feet
- c.736 square feet✓
- d.1,056 square feet
Each room's walls are 2 × (12 + 11) × 8 = 368 square feet, and two rooms make 736. Three hundred sixty-eight is one room, 1,000 adds both ceilings (264 square feet) to the walls, and 1,056 multiplies one room's floor area by 8 instead of using the perimeter.CSLB C-9 study guide 13E-9 (computation questions)
A 40-foot demising wall 10 feet high gets two layers of 4 × 10 board on each side, hung vertically. How many sheets are needed with no waste?
- a.40 sheets✓
- b.80 sheets
- c.10 sheets
- d.20 sheets
One layer on one face takes 40 ÷ 4 = 10 sheets; two layers on each of two faces is four layers, so 40 sheets. Ten sheets is one layer on one side, 20 sheets is one layer per side, and 80 sheets counts eight layers. Two-ply joints are then offset between layers.VA 09 29 00 §3.2 (two-ply application)
A setting compound covers about 52 pounds per 1,000 square feet and comes in 18-pound bags. How many bags are needed for 2,000 square feet of board?
- a.5 bags
- b.6 bags✓
- c.3 bags
- d.104 bags
2 × 52 = 104 pounds, and 104 ÷ 18 = 5.8, rounded up to 6 bags. Five bags runs short, 3 bags uses one thousand square feet's worth, and 104 is pounds, not bags.USG Easy Sand data sheet (coverage, bag size)
A crew used about 47 gallons of a ready-mixed compound whose data sheet lists about 9.4 gallons per 1,000 square feet. About how much board did it finish?
- a.About 50,000 square feet
- b.About 500 square feet
- c.About 442 square feet
- d.About 5,000 square feet✓
47 ÷ 9.4 = 5 thousands, or about 5,000 square feet. Four hundred forty-two multiplies 47 by 9.4, 500 drops a zero from the per-thousand rate, and 50,000 adds one.USG Midweight data sheet (coverage)
A bid price of $24,000 was set to give the contractor a 25% gross margin on the selling price. What was the contractor's cost?
- a.$6,000
- b.$18,000✓
- c.$19,200
- d.$30,000
Margin is on price, so cost = 24,000 × (1 − 0.25) = $18,000. Nineteen thousand two hundred treats the 25% as a markup and divides 24,000 by 1.25, $6,000 is the margin amount itself, and $30,000 adds the margin to the price.CSLB C-9 study guide 13E-9 (computation questions)
Half-inch board goes on a wall with studs 24 inches on center, screwed at the Residential Code's maximum spacing without adhesive. How many screws go on one 10-foot stud line?
- a.16 screws
- b.10 screws
- c.8 screws
- d.11 screws✓
At 24-inch framing the wall screw spacing is 12 inches, so 10 feet takes 10 spaces and 11 screws. Eight screws uses the 16-inch spacing that applies only at 16-inch framing, 10 screws forgets the end screw, and 16 screws has no basis.CRC Table R702.3.5
A ceiling has 10 flat seams, each 12 feet long, and no other joints. How many lineal feet of tape do the seams take, before waste?
- a.60 lineal feet
- b.22 lineal feet
- c.120 lineal feet✓
- d.240 lineal feet
Ten seams × 12 feet = 120 lineal feet. Twenty-two adds the numbers instead of multiplying, 240 counts each seam twice, and 60 counts half the seams. The federal specification lets tape be paper or mesh as the manufacturer recommends; the footage is the same.UFGS 09 29 00 (joint tape)
A room has six outside corners 8 feet tall and a soffit with two exposed edges 14 feet long. How many lineal feet of corner bead are needed, before waste?
- a.76 lineal feet✓
- b.62 lineal feet
- c.104 lineal feet
- d.48 lineal feet
Corners: 6 × 8 = 48 feet; soffit edges: 2 × 14 = 28 feet; total 76. Sixty-two counts one soffit edge, 48 counts the corners only, and 104 doubles the soffit edges. Corner bead is a gypsum board accessory under ASTM C1047.CBC Table 2506.2 (accessories, ASTM C1047)
One manufacturer lists its 1/2-inch regular glass-mat panel at a nominal 2.0 pounds per square foot. About what do 50 sheets of 4 × 8 panel weigh?
- a.3,200 pounds✓
- b.64 pounds
- c.3,840 pounds
- d.1,600 pounds
One sheet is 32 square feet × 2.0 = 64 pounds, and 50 sheets weigh 3,200 pounds. Sixty-four pounds is a single sheet, 1,600 pounds is 25 sheets, and 3,840 pounds uses the same sheet's 2.4-pound figure for its 5/8-inch Type X glass-mat panel.USG glass-mat panel data sheet (weights)
Besides the C-9 definition, which classification's definition also names textures among the materials it applies?
- a.C-2 Insulation and Acoustical
- b.C-22 Asbestos Abatement
- c.C-35 Lathing and Plastering
- d.C-33 Painting and Decorating✓
The C-33 definition lists "paints, papers, textures, fabrics" among its materials. The C-2 definition covers insulation and preformed acoustical materials, C-35 covers plaster coatings and lath, and C-22 is the asbestos abatement classification named in the asbestos certification statute.CSLB classification pages, 16 CCR Div. 8, Art. 3 (C-33, C-2, C-35); B&P §7058.5
Metal corner bead for gypsum board must conform to which standard named in the Building Code?
- a.ASTM C1396
- b.ASTM C1178
- c.ASTM C1047✓
- d.ASTM C557
Table 2506.2 lists "Accessories for gypsum board" under ASTM C1047. ASTM C1396 is gypsum board, C557 is adhesive for fastening board to wood framing, and C1178 is glass mat gypsum backing panel.CBC Table 2506.2
Adhesive used to fasten gypsum board to wood framing must meet which standard under the Building Code?
- a.ASTM C954
- b.ASTM C557✓
- c.ASTM C1047
- d.ASTM C475
Table 2506.2 lists ASTM C557 for "Adhesives for fastening gypsum board to wood framing." ASTM C475 covers joint compound and tape, C954 covers screws for heavier steel, and C1047 covers accessories.CBC Table 2506.2
Glass mat gypsum backing panel used behind tile is manufactured to which standard?
- a.ASTM C1177
- b.ASTM C1178✓
- c.ASTM C1278
- d.ASTM C1766
The Building Code lists glass mat gypsum backing panel under ASTM C1178. ASTM C1177 is glass mat substrate used as sheathing, C1278 is fiber-reinforced gypsum panel, and C1766 is factory-laminated panel.CBC Table 2506.2
Under the evaluation report for one maker's cold-formed steel studs and track, what designation must each nonstructural member carry?
- a.The letters "NS"✓
- b.The letters "LB"
- c.The word "STRUCTURAL"
- d.A red paint stripe
The report requires that "For nonstructural members, each member must have the designation 'NS'." "LB," a paint stripe and "STRUCTURAL" are not the marking it requires.ICC-ES ESR-5236
In the federal gypsum board specification, what thickness is listed for Type X (special fire-resistant) regular board?
- a.1/4 inch
- b.1 inch
- c.5/8 inch✓
- d.3/8 inch
The specification lists Type X board as "1200 mm 48 inch wide, 15.9 mm 5/8 inch thick." Three-eighths and 1/4 inch are thinner products (1/4 inch is its flexible panel), and 1 inch is a shaftwall or gypsum-stud thickness, not Type X board.UFGS 09 29 00 §2.1.1.3
A supplier offers to deliver board to a site where it will sit in a closed trailer reaching 140°F in summer. What do the federal specification and a manufacturer's data sheet say?
- a.Board must be stored above 140°F to cure
- b.Wrapping makes the temperature irrelevant
- c.Board is unaffected by heat when dry
- d.Do not store it above 125°F✓
The federal specification says "Do not store panels where temperatures may exceed 52 deg C 125 deg F," and one manufacturer says to avoid sustained temperatures above 125°F. Dryness and wrapping do not lift the limit, and board does not need heat to cure.UFGS 09 29 00 §1.4.2; USG Firecode X data sheet