Typical Floor Joist Spacing

Joist span and spacing is set by your local building code.

Typical floor joist spacing.

2 grade of douglas fir are indicated below. See the image below for an example of joists spaced 16 on center 16 o c. Span entries are listed for 2 6 through 2 12 joists and 12 in 16 in and 24 in. You should check with your local building department for construction requirements in your area.

Maximum floor joist span for no. Two options that arise could be your wider 24 and your narrower 12 options for spacing. Dead load weight of structure and fixed loads 10 lbs ft 2. Live load is weight of furniture wind snow and more.

Given that 2x8s are actually 1 inches wide it works out to be 14 inches between each joist. The floor joist spacing is the distance between the centers of any two installed joists. 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. Floor joist table joist size joist spacing maximum span 2 x 6 12 on center 10 0 16 9 1 19 2 8 7 24 7 11 2 x 8 12 on center 13 2 16 12 0 19 2 11 3 24 10 2 2 x 10 12 on center 16 10 16 15 2.

Live load 30 lbs ft 2 1436 n m 2. 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. True floor joist span calculations can only be made by a structural engineer or contractor. Normally floor joists are spaced 16 inches apart on center.

This means from the center of one upright joist to the center of the next. 1 in 25 4 mm. 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. With some structures floor joists are required to be 12 or 24 inches apart on center.

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.