Second Story Floor Joist

Second floor construction techniques follow a standard process.

Second story floor joist.

For example if you double the thickness or number of joists in a floor the distance the boards can span will increase by approximately 25. We are kirk and jessica. A 2 by 10 joist is really only 9 1 4 inches wide and a 2 by 12 is only 11 1 4 inches wide so depending upon which size joist the blueprints call for they will add the respective measurement to the thickness of the floor. 2 grade of douglas fir are indicated below.

True floor joist span calculations can only be made by a structural engineer or contractor. 1 ft 0 3048 m. Live load is weight of furniture wind snow and more. See the image below for an example of joists spaced 16 on center 16 o c.

Typically the second story floor joists will not only run the same direction as the first floor joists they will also be directly over them. Standard floor joists are usually 2 by 10 or 2 by 12 dimensional boards installed on edge. The width of a board is an important factor in determining the distance a floor joist can span playing a much larger role than the thickness. Framers construct the second story floor system to match the layout of the main floor system.

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. The actual width of those boards however isn t identical to what their name implies. Maximum floor joist span for no. Hello i am looking at building a second story room over.

The purlins that support the exterior rafters are put in the walls and then we get the floor joist on. Floor joists installed on second or third or higher levels double as ceiling joists for the level below. Dead load weight of structure and fixed loads 10 lbs ft 2. 1 psf lb f ft 2 47 88 n m 2.

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. Time to start on the 2nd floor loft.