[rabi]

Hello everybody,
I am in the middle of rebuilding my shower's floor because leaks damaged the subfloor (engineered wood). Please help me with how I can redo the subfloor without impacting the walls that surround the shower in three directions.

I've removed the floor layers, including most of the damaged subfloor. As you hopefully see in the picture, I see two I joists underneath and one joist (on the left, away from the subfloor hole) that looks like a regular one (not I shaped, not engineered), that go in front to back direction in the pictures. The back wall is external, the one the left borders a room and the one the right borders a hot tub (this wall extends around 3 ft from the external back wall and it covers the hot tub's width; you are pretty much looking at all of it).

I need to replace the subfloor, not sure how much I should cut out on the left and the right.

I would think that the left/right walls are non-load bearing, and they don't need support from the subfloor?

Would it be ok to cut the remaining subfloor up to the edge of the bottom of the walls, and simply put a new board, perhaps with blockers/ledges for support (for the bathroom pan really, not for the walls)?

Thanks in advance.

 

[Nealtw]

On the right you may have trouble tying the floor to the wall, if you can live with that I don't think there is a problem.

 

[XSleeper]

I agree. You have room to throw blocking under the wall that will also support your subfloor. But on the right the joist is too close to the wall, so if you can leave that subfloor I would. Run your skilsaw down the middle of that joist and leave the existing subfloor to the right.

 

[rabi]

Thanks for the input Nealtw.

Hi XSleeper, For a number of reasons, I want to build a curbless shower, if there is a way to make it work. It would require the new subfloor to be in sections, recessed and flush with the top of the joists.

It will require removing the remaining one inch or so of the subfloor all around. Other sides I think it's ok to do it, but on the right it will mean edge of the remaining subfloor will not be on the joist. Is there a way to make it work?

 

[Nealtw]

Thanks for the input Nealtw.

Hi XSleeper, For a number of reasons, I want to build a curbless shower, if there is a way to make it work. It would require the new subfloor to be in sections, recessed and flush with the top of the joists.

It will require removing the remaining one inch or so of the subfloor all around. Other sides I think it's ok to do it, but on the right it will mean edge of the remaining subfloor will not be on the joist. Is there a way to make it work?

Are you aiming for the floor to be level with the top of the joist or just thinner above the joists?

You could remove part of the bottom plate to allow working room on the right?

 

[rabi]

New subfloor will need to be level with the top of the joist, so that a premade pan can sit on the level of the top of the joist.

 

[XSleeper]

I'd say you need to remove some subfloor on the other side of the wall then, so that you can add blocking between joists. The blocking will be placed low enough so that you can slip subfloor under the bottom plates on each side. The other joists can get cleats glued and screwed.

 

[rabi]

Ok. I need to figure out how to do blocking on the right side, given some obstacles.

I have been researching blocking for I joists and don't have a solid source to use yet. Do you have a link/suggestions on how best to do it?

Also, two blockings or four total? I could put two near the back wall, another two...middle of the shower, or closer to the shower door.

 

[Nealtw]

I think you have fill the joist before you do any thing extraordinary

1. nail thru the web to blocks on both sides.
2. or 3/4 plywood nailed to top and bottom flange.



City inspectors never pass anything like that with out the engineers stamp.

 

[XSleeper]

Geez, I didnt even notice they were I joists. Typically you use i joists for blocking but the problem is you are dropping the subfloor down to be flush. Anytime I have done that the joists were dimensional lumber.

Maybe you would have to put 3/4" plywood gussets on the sides of all the I joists. Then you would be able to place dimensional lumber blocking (dropped down to "let in" your subfloor) between them anywhere you like. Then glue and screw cleats onto the gussets, between the blocking.

 

[rabi]

Update - I had a pro come do the subfloor and went with above the joist design, not flush. Thanks for your suggestions.