Floor Joists Capacity

Floor joist capacity max working load 3 0 kn m 2 as pdf file.

Floor joists capacity.

1 psf lb f ft 2 47 88 n m 2. Live load 30 lbs ft 2 1436 n m 2. Maximum floor joist span for no. Dead load weight of structure and fixed loads 10 lbs ft 2.

2 grade of douglas fir are indicated below. Live load is weight of furniture wind snow and more. This is the most common as the typical span is 15 feet. In this case your joists are adequate to support a 30 psf live load and 10 psf dead load.

The floor joist spacing is the distance between the centers of any two installed joists. Bci joist span and size charts available for download. Reading the table you ll see that 2 x 8s installed 16 apart on center can span 12 4. The span table for a 30 psf live load 10psf dead load floor indicates a required fb value of 1 315 and a minimum e value of 1 800 000.

See the image below for an example of joists spaced 16 on center 16 o c. Floor joist capacities max working load 3 0 kn m 2 floor joist capacities for timber grade c 18 c 24 and c 30 joist center space ranging 300 to 600 mm are indicated in the diagram below. Also available for the android os. In the example the joists have a spacing of 16 inches and a span of 11 feet 2 inches.

With these factors the lightest joist will have a maximum span of 17 feet 8 inches. 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. Span calculator for wood joists and rafters also available for the android os. 1 ft 0 3048 m.

For example a floor joist at 16 spacing s that can carry 53 pounds per linear foot would translate into a 318 pound single point load at its center. 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. Joist span and spacing is set by your local building code. So our house would look like the picture below with all floor joists 2 x 8.

True floor joist span calculations can only be made by a structural engineer or contractor. Location and configuration of heavy loads should be looked at on a case by case basis. The heaviest joist along with the above factors will span a maximum of 23 feet 8 inches. You should check with your local building department for construction requirements in your area.