Sister Cracked Floor Joist

Pump up the jack until the post pushes closed the crack in the joist.

Sister cracked floor joist.

Since this is a repair of a faulty or damaged floor joist it is imperative to do this project correctly and there are a few big mistakes to avoid. Tools materials required. Slip an old work metal joist hanger onto the end of the joist. When the sagging joists are level apply a generous bead of construction adhesive to the existing joist.

But it s usually best to run the sister joist over the entire span. If a crack or sag is isolated to one area the sister joist should extend at least 3 ft. On both sides of the problem area. Structural screws and joist hangers if applicable.

Fixing broken cracked sagging floor joists. If needed notch the bottom edge of the sister joint so it fits over the foundation or beam. I suppose somewhere in the world there are floor joists that need to be repaired that have wide open clear joist bays with no pipes wires or obstructions. Squeeze a generous amount of carpenter s glue into the crack in the floor joist.

Properly sistering floor joists is very important and should not be rushed to save time. Cut a sister joist the same length as the damaged joist. 2 x 4s together to make a cross beam then place the beam perpendicular to the joists near one end of the joists. Place it next to the damaged joist with the crown side up.

Position a 2x4 post and hydraulic jack directly beneath the cracked end of the joist.