How To Repair A Broken Roof Joist

Tack a beam under the sagging joists.

How to repair a broken roof joist.

Pictured is joist repair method for end rotted joist using plywood and some suggestions for best practice. Identify the cracked or sagging joist before it causes additional problems. 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. Secure the patch on one side of the break with the wood screws and have your helper apply up pressure until the truss in realigned.

With the proper tools anyone can do this. Place a level on the bottom edge of the joist to determine the amount of sagging that has occurred. Use a c clamp on each end to hold the patching in position. 6 drill pilot holes for the bolts on each side of the crack.

If the repair was engineered then the repair technique would be drawn out on paper stamped with the engineers approval stamp and it would list the number and type of fasteners needed. Step 3 fixing the planks or plates. Identify and mark the joists needing repairs. Get to the roof and find out the extent of the damages on the joists.

I recently had to repair a broken floor joist that had cracked. Step 3 cut new roof joist. Nailing two 2x4s together will work to span about three joists unless the sag is under a weight bearing wall. Place the 4 foot board against the flat side of the broken truss making sure that the same amount of patch rests on either side of the break or that the break is centered in the middle of the patch.

How to repair a roof joist. Step 5 add. Remove any blocking or bridging above the sill or beam where the sister joist will go. Use your tape measure to record the distance of both rafter legs.

Use a circular saw to cut two sets of new rafters from the same size wood by the same dimensions. Step 4 place the new roof joist into position. In order to get at the broken roof joist you will need to either go into the attic or remove the ceiling tiles. Repeat the process for the joist beneath your old roof rafter.

Step 1 initial preparation. Jacking them up too fast may cause cracks in the walls and floors overhead. How to repair a cracked or sagging joist. Step 2 measure roof joist.

Fixing broken cracked sagging floor joists. Set a hydraulic jack and post under the beam and jack up the joists about 1 8 in. Step 2 marking the positions. Very easy to do.

Place one piece of patching material on each side of the joist. Click the image to enlarge. Step 1 locate broken roof joist. Measure the dimensions of the old rafters beneath your roofing surface.

This video shows how to repair a split rafter.