Joining Two Floor Joists

Learn how to make structural repairs by sistering floor joists.

Joining two floor joists.

If there was water damage make sure that whatever leaky pipe or condensation issue caused the rot is fixed. Common sense tells you that large floor joists can carry more load and spacing joists closer together also increases the load bearing capacity of a floor. This is unusual in new deck construction and would only be necessary for very long spans that exceed the length of your longest boards. The floor joist spacing is the distance between the centers of any two installed joists.

Tack a beam under the sagging 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. The extra two inches of vertical distance when a floor is framed with 2 x 10 joists rather than 2 x 12s can be quite important for example. Nailing two 2x4s together will work to span about three joists unless the sag is under a weight bearing wall.

These problems must be addressed firsthand prior to implementing any restoration steps. Family handyman deck board spacers. A day until they re level. Some allowances can be made on the length and thickness of the plywood gussets to suit your particular needs.

Most often floor joists need to be sistered because of two problems either water damage which leads to rot or termite damage that crumbled the joist. But larger is not always better when builders are constructing a home or adding a room addition. The joists need to cover a span of 136. There is a decent amount of storage space to be gained if i add some joists and plywood flooring in the roof area.

Sistering or joining joists the term sistering joists is the practice of overlapping two joists by a certain distance across a beam to create an extended joist. While it is prudent to over engineer your repair. These yellow deck board spacers can be used to space boards either 1 8 in. Pictured at left is a diagram of some recommend prescriptive repair techniques for floor joists.

You need to know these modern deck building tips and tricks. Then set new joists same height as existing ones alongside the old. It may be acceptable to use 1 2 plywood or a somewhat shorter gusset depending. I have several 2x6 s from another project but they are only 75 long.

Set a hydraulic jack and post under the beam and jack up the joists about 1 8 in.