Strengthen Attic Floor Joists

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

Strengthen attic floor joists. Sistering is the process of adding a new joist next to each existing joist. I went to get a permit from the city to finish the attic and they said i needed to reinforce the floor since for a live load it was not strong enough for our span below about 12. Nailing two 2x4s together will work to span about three joists unless the sag is under a weight bearing wall. If your attic joists won t bear the weight necessary to finish out a living space but the engineer cleared them to support floor decking for light storage you can install inch plywood or.

This is a great answer. A steel plate can be used the same way. Plywood firmly fastened to the undersides of joists helps prevent this side to side bending and stiffens the floor. Jacking them up too fast may cause cracks in the walls and floors overhead.

Strengthening attic joists for live loads by sistering if the attic joists are not adequate one way to strengthen the floor for live loads is to sister the old joists. In my 80 year old house the attic had 2x6 floor joists about 16 oc. Tack a beam under the sagging joists. A day until they re level.

Pretty sure you mean joists not rafters rafters are the sloped members that run directly under your roof whereas joists are the horizontal members that sit atop the ceiling of the floor below the attic. A layer of 3 4 in. You can however strengthen the joists by securing another length of wood to the existing joist called sistering or reduce wobbly floors with block inserts between the joists called. Gluing and screwing a 3 4 attic subfloor and providing solid bridging should also be considered.

For this fix to work well the upper edges of the joists must be solidly fastened to the subfloor above. Adding a 2 x 4 along the bottom chord of the 2 x 6 ceiling floor joist maybe helpful in stiffening the joist as well. You will have to use a very sturdy piece of wood or some steel plating to reinforce the floor joists. I recommend three gusset pairs per joist at the quarter points one about every 3 feet.

Squeaks in a floor usually mean that the subfloor has loosened from the joists.