Height Of Floor Joists

Maximum floor joist span for no.

Height of floor joists.

Live load is weight of furniture wind snow and more. Even though we use 1 pt lumber the joists are often slightly warped or vary in depth at times causing adjacent joists to differ in height by as much as 1 2 inch or more. 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 floor joist spacing is the distance between the centers of any two installed joists.

2 grade of douglas fir are indicated below. Dead load weight of structure and fixed loads 10 lbs ft 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. Standard floor thickness however is substantial in order to provide the strength necessary for bearing the weight of the walls the ceiling and the roof.

1 psf lb f ft 2 47 88 n m 2. True floor joist span calculations can only be made by a structural engineer or contractor. Setting the joists perfectly level at the house is easy and the beam makes them fairly even near the front edge but the problem is in the middle. In joist sizes the larger size such as 6 inches represents the height of the joists while the 2 inch size represents the joist width or the area on which the floorboards sit.

Two by 6 inches is a joist size frequently used in both indoor floors and as deck joists.