A 12-foot ledger is laid out for deck joists at 16 inches on center with a joist at each end. How many joists are needed?
Correct Answer
A) 10 joists.
Twelve feet is 144 inches. At 16 inches on center, 144 / 16 = 9 spaces, so 10 joists are needed including both ends.
Why This Is the Correct Answer
Twelve feet is 144 inches. At 16 inches on center, 144 / 16 = 9 spaces, so 10 joists are needed including both ends.
Why the Other Options Are Wrong
Option B: 9 joists.
9 joists. is below the supported result for deck framing layout; it likely uses the wrong base, period, or account bucket.
Option C: 11 joists.
11 joists. is above the supported result for deck framing layout; it likely adds an unsupported amount or compares the wrong financial base.
Option D: 12 joists.
12 joists. is above the supported result for deck framing layout; it likely adds an unsupported amount or compares the wrong financial base.
Memory Technique
Feet and inches live in different drawers; Laying Out tells which opens.
Reference Hint
Study anchor (closed-book): memorize Deck framing layout from California Residential Code, California Code of Regulations Title 24. / Title 24 California Residential Code deck joist layout concepts; know the rule or calculation trigger without relying on exam-room lookup.
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