Fix illegal notch in joist

acerunner

There is a notch in the center of a 2x10 joist. Obviously that is illegal. It can only be notched on the outside 3rd.

So to fix it, I'm either going to sister another 2x10, or sandwich the joist between two 3/4" structural plywood.

My question is does the sister joist need to be the full span of the joist, or just in the center of the joist where the notch is.

Just Bill

The longer you span the notch, the better, but I would say at least 4' on either side. Glue/screw the pieces together.

acerunner

thanks. ur right, longer would be better. I just worry I won't be able to squeeze it over the top plates on both ends.

Gary in WA

Try a search here, I know I answered it has to be within the depth of the joist for a full sister. But your situation is different, just a scab each side, try to replace a chunk of solid lumber in the notch for compression with glue.

Gary

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FinalSay

As an home inspector in Ontario I would question a repair/sister that was not full length; any other type of repiar would need a P Eng apporval.

acerunner

is there a preference for full 2x10 sister, or plywood sandwich?

Tizzer

This joist is a ceiling joist? How's a home inspector going to see it covered in sheetrock?
If you feel the need to go wall to wall with the sister joist, cut it a couple or so inches short. Each end is still bearing, plug the notch with a chunk of wood as mentioned, and nail up the sister.
How big a notch is it?

acerunner

It's a two story home. This is the joists in between. I am remodeling the lower floor so sheetrock is ripped out and I uncovered this error.

The notch is about 2" wide, 2" deep. Nothing was running through it, so not sure why it was notched to begin with.

Daniel Holzman

The mechanics of a joist are that it carries approximately uniform load, meaning that the maximum moment occurs at the center of the joist, and drops off rapidly towards the supports, where there is zero moment. Therefore, there is no need to sister anything but approximately the middle 40 percent of the joist. Feel free to carry the sister joist all the way to the walls, but since the critical load is at the center of the joist, and shear at the ends almost never controls, it adds nothing to the ultimate capacity of the joist to carry the sister joist to the walls.

It is necessary to use a sufficient number of approved fasteners (typically common nails, but you can use approved screws or bolts as well) to insure that the moment is transferred from the damaged joist to the sister joist. Typically the pattern is a 16p common nail every six inches, with two on either end, assuming you cover the middle 40 percent of the joist, however this is simply standard practice, it is possible to compute the required nailing pattern based on the size of the joist, the type of wood, the load, and the type of fastener. I have never seen such a computation carried out for a sister project, although as I said in theory it can be done.