Strengthening Roof Joists

Long spans of joists in newer homes may wobble or bounce from foot traffic.

Strengthening roof joists.

Sistering is the process of adding a new joist next to each existing joist. As incremental parts of a building s structure joists are not easily replaced. You can however strengthen the joists. Add an additional row of fas teners midway between the joists to pull the layers tightly together.

Joists and orient panel ends over joists. To prevent sag in 2x6 s and strengthen at same time you could secure lengths of stainless steel or galvanized cable attach at each end of individual ceiling joists have cable go over a one or two spreaders or strut projecting down from the underside of the ceiling joist maybe 12 14 or so as not to lose too much headroom these could. Strengthening existing roof rafters is a difficult process that often requires professional help. Choose ring shank nails or screws that are long enough to penetrate the joists by 11 2 in and space them every 6 in.

When installing on the underside of the joists the process is the same. In the case of 2x6 joists you can pair them up with additional 2x6 joists by nailing them together side by side. Laminated and single piece beams are often reinforced with plywood. If you have a stick frame roof there are a few basic techniques that you can use to strengthen your rafters.

If the attic joists are not adequate one way to strengthen the floor for live loads is to sister the old joists.