Floor Joist Sizing Chart

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

Floor joist sizing chart.

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. Maximum floor joist span for no. Floor joist span tables for various sizes and species of wood. A lot of questions revolve around joists when it comes to building a deck.

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. 2x10 to 15 feet and 2x12 to 18 feet. What is the proper placement. Dead load weight of structure and fixed loads 10 lbs ft 2.

How do i keep them even. 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. Live load is weight of furniture wind snow and more. 1 psf lb f ft 2 47 88 n m 2.

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. How far apart are floor joists placed. 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. A 2x8 up to 12 feet.

True floor joist span calculations can only be made by a structural engineer or contractor. See the image below for an example of joists spaced 16 on center 16 o c. 2 grade of douglas fir are indicated below.