Second Story Floor Framing Joist Size

You should check with your local building department for construction requirements in your area.

Second story floor framing joist size.

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. Looking at this table you will see there is a choice in the size of floor joist 2 x 6 2 x 8 2 x 10 or 2 x 12 and there is a choice in the joist spacing 12 16 or 14. 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. Builders can adjust their choice of lumber size and spacing depending on circumstances.

A 2x8 up to 12 feet. 2x10 to 15 feet and 2x12 to 18 feet. With some structures floor joists are required to be 12 or 24 inches apart on center. Live load is weight of furniture wind snow and more.

Normally floor joists are spaced 16 inches apart on center. Given that 2x8s are actually 1 inches wide it works out to be 14 inches between each joist. Dead load weight of structure and fixed loads 10 lbs ft 2. Once the rim joist is in place which creates a frame around the perimeter of the second story floor you ll install the floor joists which are the same dimension as the rim joist.

This means from the center of one upright joist to the center of the next. The floor joist spacing is the distance between the centers of any two installed joists. In typical deck construction with a ledger on one side of the joist and beam on the other the size of the joists is driven by the size of the deck and based on the general maximum spans mentioned above. The 2x12 lumber that i picked up a few weeks ago is perfect.

1 psf lb f ft 2 47 88 n m 2. Joist span and spacing is set by your local building code. What this means is that the first story ceiling joists will also serve as the floor joists for the second story. Floor joists align with the wall studs which align with the first story floor joists.

While first floor supports are needed to account for the additional weight of a second floor the walls are pretty much the same as those of a single story home. The joists are so straight that i can t hardly find the crown in the lumber. Maximum floor joist span for no. See the image below for an example of joists spaced 16 on center 16 o c.

The larger the deck the larger the joists.