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Joist
A joist is a horizontal framing member that supports a floor or ceiling.
Why it matters
Joists carry weight. Their size, spacing, and span affect how bouncy or solid a floor feels and how much weight it can safely support.
Where people get this wrong
A joist is not the same as a beam. Beams support joists. Cutting or notching joists incorrectly can weaken the floor.
Real-world example
A floor feels bouncy when you walk across it. The joists may be undersized for the span, or they may be damaged or improperly supported.
Where this hits your build
This shows up during framing. Once walls are up and covered, you lose access. The pre-drywall walkthrough is your window to verify.
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