Floor Joist Leveling By Sistering

Sistering joists means beefing them up with additional material.

Floor joist leveling by sistering.

This job can run you 1 000 and 5 000 depending on the extent of the job. On the top side of the floor another fix it idea to lay down new hardwood over the existing floor. But it s usually best to run the sister joist over the entire span. A plywood subfloor will bridge any minor waves in the existing floor and leveling compound would help too.

Lay a new 3 4 plywood subfloor and bob s your uncle. You will have to make sure your joists can handle the addition of considerably more weight from the plywood subfloor and any floor coverings. Our 60 year old floor joists are showing their age. The amount of weight that each floor joist handles is pretty amazing.

Sistering is a. Driving 16d common nails in old hard wood is difficult. You will have a level sound surface to lay your new floor on. It is important to jack this end level to keep the floor from sagging any more and to keep the joists from splintering later.

I have a floor joist that i noticed has several large knots that have split vertically through the joist. My plan is to use construction adhesive and tack it into place with nails. Doing so strengthens weak joists and can help straighten sagging joists. Here s how we are correcting the problems.

How to sister a floor joist. Sistering joists is a job for the pros who will bolt the new joists to the old joists and position the ends of the joists on the same sill plate that supports the original joists. When sistering these pieces together it is easy to put just a few nails in the boards and move on. When the sagging joists are level apply a generous bead of construction adhesive to the existing joist.

Then sister the joists will lvl joists at exactly the level you want. Now that said when you have a major humpy floor you should bite the bullet and remove the subfloor planks down to the joists. I forgot to mention the construction adhesive in between them. To permenantly secure the joist i will use 1 2 inch carriage bolts in sets.

I am going to sister this joist with an identical sized joist 2x10 over its full length. If you have an uneven floor you may need to think about leveling floor joists with shims.