Floor Joist Sizing Chart

How far apart are floor joists placed.

Floor joist sizing chart. 2 grade of douglas fir are indicated below. A lot of questions revolve around joists when it comes to building a deck. True floor joist span calculations can only be made by a structural engineer or contractor. How do i keep them even.

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. 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. Dead load weight of structure and fixed loads 10 lbs ft 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.

1 psf lb f ft 2 47 88 n m 2. 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. See the image below for an example of joists spaced 16 on center 16 o c. In general terms joists spaced 16 inches on center can span 1 5 times in feet their depth in inches.

1 ft 0 3048 m. A 2x8 up to 12 feet. 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. What is the proper placement.

Floor joist span tables for various sizes and species of wood. Joist span and spacing is set by your local building code. Live load is weight of furniture wind snow and more.