A 21-foot partition wall is framed at 16 inches on center with a stud at each end. How many layout studs are needed before openings?
Correct Answer
A) 17 studs.
Twenty-one feet is 252 inches. At 16 inches on center, 252 / 16 = 15.75 spaces; round up to 16 spaces and add one end stud for 17 studs.
Why This Is the Correct Answer
Twenty-one feet is 252 inches. At 16 inches on center, 252 / 16 = 15.75 spaces; round up to 16 spaces and add one end stud for 17 studs.
Why the Other Options Are Wrong
Option B: 16 studs total.
16 studs total. is below the supported result for wall framing layout calculation; it likely omits allowance, conversion, coverage, or final round-up.
Option C: 18 layout studs.
18 layout studs. is above the supported result for wall framing layout calculation; it likely double-counts allowance, uses the wrong unit, or rounds too early.
Option D: 19 marked studs.
19 marked studs. is above the supported result for wall framing layout calculation; it likely double-counts allowance, uses the wrong unit, or rounds too early.
Memory Technique
Laying Out takeoff: count the condition before counting the package.
Reference Hint
Study anchor (closed-book): memorize Wall framing layout calculation from California Residential Code, California Code of Regulations Title 24. / Title 24 California Residential Code wall framing layout concepts; know the rule or calculation trigger without relying on exam-room lookup.
More Class B Trade Questions
A 2-inch horizontal sanitary branch must be installed at 1/4 inch fall per foot. What total fall is needed over a 24-foot run?
A 4-inch building drain is laid out with a required 1/8 inch fall per foot. What fall is required across 40 feet?
A rooftop unit schedule shows 3 tons of cooling. Using 12,000 Btu per hour per ton, what cooling capacity is this?
A pump motor is listed as 2 horsepower, and the coordination table asks for watts. Using 746 watts per horsepower, what is the approximate motor power?
A slab is 30 feet long, 18 feet wide, and 4 inches thick. How many cubic yards of concrete are needed before waste?
A footing is 80 feet long, 2 feet wide, and 12 inches deep. How many cubic yards of concrete are required before waste?
A patio subgrade must drain at 2 percent away from the building for 20 feet. What total drop is required?
A building pad needs 150 compacted cubic yards of fill. If the borrow material shrinks 10 percent after compaction, about how many loose cubic yards should be hauled in?
A roofing estimate shows 2,850 square feet of roof area. How many roofing squares is that?
A waterproof deck surface is 14 feet deep and must slope 1/4 inch per foot to the drain. What vertical fall is needed?