Roof Deck Joists Span

The 2015 irc includes a new table r507 5 deck joist spans for common lumber species.

Roof deck joists span.

Joist spacing for composite decking. Also available for the android os. Two by twelve douglas fir joists spaced 12 inches apart on center for example can span 20 feet 7. Some builders reduce joist spacing to 12 on center to strengthen the deck frame or to increase maximum allowable joist spans.

To learn more about deck joist sizing spacing and allowable span reference this chart. As a rule the larger the deck the larger the joists. Most decks use 16 on center spacing for joists. The closer the joists are to each other the greater the distance they re able to span safely.

Before building a composite deck always read the installation instructions from the manufacturer paying. The table makes it easier for deck builders to accurately size deck joists and for inspectors to check decks for adequate framing. Span calculator for wood joists and rafters also available for the android os. Ready to start calculating how much lumber you ll need for your joists.