Lumber span reference
Look up allowable spans straight from the published code tables — floor joists, ceiling joists, rafters, and decks — for every species, grade, size, and spacing. Instant lookup, a deck calculator, and a “what size do I need” reverse tool. Every value cites its source.
SPF #2 floor joist, 40 psf live load
Every framing member
Each table is reproduced verbatim from its published source, cited on the page.
Floor joist
Floor joistsHorizontal members that carry a floor's live and dead load between supports.Rafter
RaftersSloped roof members that carry roof and snow loads down to the walls.Ceiling joist
Ceiling joistsHorizontal members that carry a ceiling and any limited attic storage.Decks
Deck joists & beamsDCA6 deck joist spans, overhangs, and beam sizes for residential decks.Popular lookups
Plan a whole build
The project planner lets you add each floor, roof, or deck member, check it against its published span, and — with Premium — pull a material takeoff and a printable inspector sheet. It runs entirely in your browser — no account, no sign-up.