Loft Floor Joist Thickness

True floor joist span calculations can only be made by a structural engineer or contractor.

Loft floor joist thickness.

I m building a loft above my garage for storage. 19 32 and 5 8 inch thick panels require joists spaced 20 inches on center. If you plan on placing the plywood around the perimeter of the opening or door and using it only to store light boxes or materials 1 2 inch thick plywood should suffice. The thicknesses are as follows.

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. Though joists may be any size that you desire using typical floor joist and beam specifications ensures that you can find hardware to fit the joists and that the floor provides adequate support for furniture and other items in a room. If the attic joists are not adequate one way to strengthen the floor for live loads is to sister the old joists. 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.

Existing loft joists are designed only to support ceiling boards so a structurally sound floor is needed. 7 16 15 32 and 1 2 inch thick panels require joists spaced 16 inches on center. No matter what the spacing is on your ceiling joists 3 4 inch plywood should be used if you plan on walking on it. Floor joists or beams provide the below surface support for the wood subfloor of a room.

Sistering is the process of adding a new joist next to each existing joist. Loft floors loft floor construction. Ceiling joists consist of two narrow low grade timbers often bolted together sistered above a supporting wall.