JoistLedger is an independent site that publishes deck framing spans and works out framing quantities.
It exists because span tables are published, free and almost unreadable — printed as grids of species, grade and spacing that you have to cross-reference three times before you know whether a 2×10 will do.
Where the numbers come from
- IRC Table R507.5 for joist spans, with all four of its assumptions stated on every page
- IRC R507.5.1 for the cantilever limit of one quarter of the actual span
- IRC R507.9 for ledger attachment, which is what actually fails when decks collapse
Every page states the source and the assumptions behind its figures, because a number without its assumptions is not much use. Where a limit comes from a code table rather than a calculation, the page names the table.
Species buys you a foot
Species is worth about a foot of span. The same 2×10 at 16 inches on center spans 14′ 0″ in Southern Pine and 13′ 0″ in redwood or cedar — same code, same size, and nobody mentions it at the register.
What this site does not do
We do not design decks carrying hot tubs, roofs or unusual loads, and we do not replace a permit. Local codes amend the IRC and high-snow jurisdictions use higher live loads.
Who runs it
One person who has built enough decks to know which numbers actually get looked up. There is no editorial team here. The check is simpler than one: every span on this site names its species, grade and the code table it was read from.
The framing maths is written as code and run across every span, spacing and species combination on the site, which is how a mistake in one constant becomes visible instead of staying hidden. When something is wrong it gets fixed, with a note recording the change.
How it is paid for
JoistLedger is free to read and funded by display advertising. Nothing here is sponsored and there are no affiliate links; no lumber supplier has any influence on these numbers.
Getting in touch
Corrections and questions go to [email protected]. A correction is the most valuable message this site receives — the editorial policy says what happens to one.