JoistLedger is an independent site that publishes deck framing spans and works out framing quantities.
It exists because the answers to these questions are mostly published somewhere already — in code tables, manufacturer datasheets and industry standards — and almost none of it is available in a form you can actually use while standing in a merchant's yard.
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 constant is a convention rather than a measurement, we say so.
Species is worth about a foot of span…
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, working on this alongside other things. There is no editorial team and we are not going to invent one — what should earn your trust is that every figure on the site names the standard it came from, so you can check it yourself.
Calculations are written as code and tested against every combination they can produce, rather than typed into a page by hand. When we get something wrong we correct it and leave a note.
How it is paid for
JoistLedger is free to read and funded by display advertising. There are no sponsored placements and no affiliate links on the site; nothing here changes based on who sells the product.
Getting in touch
Corrections and questions go to [email protected]. Corrections are the most useful thing you can send — see the editorial policy for how we handle them.