Repairing notched joist

[Rollin]

The last owner of our house has notched 4 floor joists in an upstairs bathroom . The span is about 12 feet and the notches are about 3 inches deep and right in the middle of the span.

Can this be repaired or do I have to get new joists fittted?

Bear in mind that a new bath is going to be sitting on top of them eventually.

[B17NNS]

You could lift the boards and bolt new joists to the existing to beef them up.

[m3jappa]

From that picture it actually doesnt look too bad, the guidlines on notching joists are imo (and the opinion of a few good builder friends) a little excessive.

That said i would still re inforce them by adding some extra timber, for example if its an 8" joist with a 3" notch i would add some 5x2 or 4x2 whatever you can get and then span maybe 600 either side of the notch and fit with a few coachbolts.

[Blakeatron]

B17NNS said:

You could lift the boards and bolt new joists to the existing to beef them up.

yep similar sized stock bolted either side of the current joist.

Or if that a abathroom you will have to level the floor with soemthing before tiling - can you not sit the bath on a thicker panel on top of the floor boards to spread the load?

[King Herald]

Yes, bolt a couple of stiffener planks to each side as mentioned, but I'd use some good wood glue at the same time, be stronger than the original then.

[Rollin]

I may end up having to use one of the notches, so is it possible to reinforce each side up to the bottom of the notch?

[DocJock]

A steel plate either side?

[Rollin]

Thats what I think.

[Paul Drawmer]

At the top of the joist, it's in compression. A couple of 18mm ply planks each side of the notch, extending 300mm each side of the notch and glued and screwed every 20mm should do fine.

[m4ckg]

Paul Drawmer said:

At the top of the joist, it's in compression. A couple of 18mm ply planks each side of the notch, extending 300mm each side of the notch and glued and screwed every 20mm should do fine.

^^^^^ this for me, use polyurethane glue known as p u, very strong and expands to fill any voids

[silverthorn2151]

Paul Drawmer said:

At the top of the joist, it's in compression. A couple of 18mm ply planks each side of the notch, extending 300mm each side of the notch and glued and screwed every 20mm should do fine.

I agree, I would tend to stiffen them with some ply. Screw the ply to the sides of the joists with a pretty full pattern. 3 rows, top middle and bottom would do it.

Get an 90 degree angle attachment for your drill to make life easier.