A stair layout has 13 treads at 10 inches each. What total horizontal run is needed?
Correct Answer
A) 130 inches.
Thirteen treads at 10 inches each require 130 inches of horizontal run.
Why This Is the Correct Answer
Thirteen treads at 10 inches each require 130 inches of horizontal run.
Why the Other Options Are Wrong
Option B: 120 inches.
120 inches. is below the supported result for stair layout calculation; it likely omits allowance, conversion, coverage, or final round-up.
Option C: 140 inches.
140 inches. is above the supported result for stair layout calculation; it likely double-counts allowance, uses the wrong unit, or rounds too early.
Option D: 156 inches.
156 inches. is above the supported result for stair layout calculation; it likely double-counts allowance, uses the wrong unit, or rounds too early.
Memory Technique
Stair Layout memory for Checking Framing: treads make the run; risers make the climb.
Reference Hint
Study anchor (closed-book): memorize Stair layout calculation from California Residential Code, California Code of Regulations Title 24. / Title 24 California Residential Code stair geometry concepts; know the rule or calculation trigger without relying on exam-room lookup.
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