Rough Guide On Sizing Floor Joists

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.

Rough guide on sizing floor joists. To come up with the deflection limit divide the joist span length with a number. Maximum floor joist span for no. Floor joist span tables for various sizes and species of wood. Let s expand our house beyond that 17 2 span capability to 24 feet wide.

Dead load weight of structure and fixed loads 10 lbs ft 2. 9030 floor. The optimum deflection limit on your floor joist is an inch for every 360 inches. Tj 9001 installation guide for floor and roof framing with tji 110 210 230 360 and 560 joists.

1 ft 0 3048 m. Step 4 determining the live load. True floor joist span calculations can only be made by a structural engineer or contractor. 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.

Joist span and spacing is set by your local building code. 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. Most of the time the length is divided by 360 inches. 2 grade of douglas fir are indicated below.

The maximum allowable diameter of a hole in any solid lumber joist is one third of. 5036 usp connector guide for trus joist products. Though joists may be any size that you desire using typical floor joist and beam specifications ensures that you can find hardware to fit the joists and that the floor provides adequate support for furniture and other items in a room. Tj 9006 installation guide for deep depth tji 360 560 and 560d joists.

See the image below for an example of joists spaced 16 on center 16 o c. Live load is weight of furniture wind snow and more. So the house dimensions will now be 24 x 13. Tj 9510 installation guide for floor and roof framing with tji s31 s33 and s47 joists east canada.

1 psf lb f ft 2 47 88 n m 2. 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. The floor joist spacing is the distance between the centers of any two installed 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.

The widest span in the floor joist span table in part 2 of this tutorial module showed that floor joists can span 17 2 if they are 2 x 12s spaced 12 o c.