Floor Joist Leveling By Sistering

You will have a level sound surface to lay your new floor on.

Floor joist leveling by sistering.

Now that said when you have a major humpy floor you should bite the bullet and remove the subfloor planks down to the joists. Sistering is a. On the top side of the floor another fix it idea to lay down new hardwood over the existing floor. Then attach the sister joist using three 16d common nails driven every 16 in.

Lay a new 3 4 plywood subfloor and bob s your uncle. I am going to sister this joist with an identical sized joist 2x10 over its full length. A plywood subfloor will bridge any minor waves in the existing floor and leveling compound would help too. Framing lumber is the typical.

If you have an uneven floor you may need to think about leveling floor joists with shims. But it s usually best to run the sister joist over the entire span. 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.

It is important to jack this end level to keep the floor from sagging any more and to keep the joists from splintering later. Our 60 year old floor joists are showing their age. You will have to make sure your joists can handle the addition of considerably more weight from the plywood subfloor and any floor coverings. 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. 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. I forgot to mention the construction adhesive in between them. Doing so strengthens weak joists and can help straighten sagging joists.

How to sister a floor joist. The amount of weight that each floor joist handles is pretty amazing. To permenantly secure the joist i will use 1 2 inch carriage bolts in sets. When sistering these pieces together it is easy to put just a few nails in the boards and move on.

Driving 16d common nails in old hard wood is difficult. This job can run you 1 000 and 5 000 depending on the extent of the job.