AMERICAN WOOD COUNCIL EXPLANATION OF TABLES 1. Construction details should be in accordance with AS16842. Table4 7 Jpg 903 596 Deck Material Calculator Deck Framing Deck Flooring These tables can help calculate whether floor joists are strong enough to support themselves and the load they carry without the help of any walls underneath. Timber floor joist span tables . View Joist Rafter Tables. Get Instant Quality Info at iZito Now. Joist span table - Use these tables to determine floor joist spans based on grade of lumber size of joist floor joist spacing and a live load of 30 lbsft 2 or 40 lbsft 2. To use the joist span calculator below first select the species of lumber you will use for your construction project from the drop-down list. Use this table to determine the maximum lengths of floor joists based on species of lumber joist spacing and joist size. SCOPE hese span tables for joists and rafters are calculated T on the basis of a series of modulus of elasticity E an...