Residential Wood Floor Joist Span Table

Residential structural design vertical structural forces we were about to start learning about floor joist span tables.

Residential wood floor joist span table.

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 lbs ft 2 or 40 lbs ft 2 these tables can also be used to determine deck joist span. Using floor joist span tables. Span tables for joists and rafters 3 american wood council table 9 1 required compression perpendicular to grain design values f c in pounds per square inch for simple span joists and rafters with uniform load. Floor joist span tables for various sizes and species of wood.

Joist span and spacing is set by your local building code. This sample table gives minimum floor joist sizes for joists spaced at 16 inches and 24 inches on center o c for 2 grade lumber with 10 pounds per square foot of dead load and 40 pounds of live load which is typical of normal residential construction. Of bearings and is based on uniformly loaded joists. Span ft 1 5 2 0 2 5 3 0 3 5 2 30 22 18 15 13 4 59 44 36 30 25 6 89 67 53 44 38 8 119 89 71 59 51 10 148 111.

The maximum span is measured o c. The minimum bearing length is 1 spans values in bold indicate that web stiffeners are required at the osb end panel. When building a house or even a deck it is important to confirm you have the correct joist sizes spans and spacing before you get started. Simplified maximum span tables for selected visual and mechanical grades of southern pine lumber in sizes 2 4 thru 2 12.

The tables permit a bearing length of up to 3 5 inches but since 1 5 is probably the worst case that you ll encounter for joist or rafter bearing it s a safe value. While most residential construction uses 2x8 joists with 16 inch spacing there are many other factors you need to consider when determining the proper joist span length. Don t worry you won t need to do a lot of calculations in determining the size and placement of the structural framing within your house design. Listed are 46 tables based on common loading conditions for floor joists ceiling joists and rafters.

The spans are based on simple span joists. You can also use the wood beam calculator from the american wood council website to determine maximum rafter and joist lengths. Apa performance rated i joists pris are manufactured in accordance with pri 400 performance standard for apa ews i joists form x720 this performance standard provides an easy to use table of allowable spans for applications in residential floor construction allowing designers and builders to select and use i joists from various member manufacturers using just one set of span. Use the span tables below to determine allowable lengths of joists and rafters based on size and standard design loads.

View joist rafter tables.