Spacing For Floor Joists

Since the example house we are designing for is 12 feet wide we need to find in the floor joist span table a joist size and centering that can span 12 or wider.

Spacing for floor joists. Maximum floor joist span for no. If adding additional framing be sure to keep all boards level and in plane across the tops. 1 ft 0 3048 m.

Wood species grade of the lumber width and thickness of the boards spacing between joists load placed on the floor length that the. Just don t go smaller further apart or a longer span. For a more rigid feel 12 or less may be preferred.

Joist spacing for composite decking. Joist span and spacing is set by your local building code. There are six choices.

Most lay outs are on 16 so the field is pre selected. See the image below for an example of joists spaced 16 on center 16 o c. 2 8 s come standard at 1 inch thick.

Below is a table giving the minimum size floor joists needed for 16 and 24 on center o c spacing when using 2 lumber with 10 pounds per square foot of dead load and 40 pounds of live load. Most decking is not strong enough to support longer spans than 16. 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.

2 grade of douglas fir are indicated below. The floor joist spacing is the distance between the centers of any two installed joists. Live load is weight of furniture wind snow and more.