How To Sister A Roof Joist

Sistering joists means beefing them up with additional material.

How to sister a roof joist.

Step 1 evaluate your situation. Driving 16d common nails in old hard wood is difficult. Calvin suggests that i joists would have been an alternative to consider at the start of the project. How much repairing floor joists should cost.

I joists would have been a good bet. Framing lumber is the typical. No sistering or modification of i joists to the existing situation he says. However doing this does not fix the slant that the floor has taken since the old joists got damaged.

Take some extra time and jack the damaged area up so that the new lumber doesn t need to be notched. Then attach the sister joist using three 16d common nails driven every 16 in. For open ceilings set scaffolding to sister a roof rafter. In his own garage he used i joists with 2 4 flanges for a 30 ft.

Predrill and drive 3 8 in. If only a few joists are rotted primarily at the bottom they can be repaired using a process known as sistering after the rot is cleaned away and the timber treated to prevent more problems a new joist is laid beside the old one and fastened to it. Before you begin floor joist repair you should examine and evaluate your current situation. When the sagging joists are level apply a generous bead of construction adhesive to the existing joist.

Insulate basement rim joists. Lag screws if you re having trouble nailing. Average costs and comments from costhelper s team of professional journalists and community of users. Consider how weakened or damaged the joists are and also whether a weight above them could be causing the joists to fail.

In attics it s best to place strips of plywood across the ceiling joist as a work platform. How to sister a floor joist.