2X3 Lumber?

Any reason I can't use 2X3s to frame my tub alcove ends? The 2" saved would sure help access to what's going to be behind the alcove.

2x3s might not feel quite as solid if/when someone might later bump up against them, but they should do fine.

2x3

a 2X3 is only 1" less than a 2x4, (not 2"), but the rigidity is considerably less. If you intend to install them flat, then the wall's integrity goes way down.

What's going on the alcove's walls? If tile, it sure isn't a good idea. If cross-braced and sheathed with ply you can recover some strength as can using smaller spacing on the studs.

If one of the alcove ends is the wet wall, that could present a challenge for the valve.

Nate R said:

...The 2" saved would sure help access to what's going to be behind the alcove.

Click to expand...

whatever that means.

no reason against using 2X3s, except strength, and space for valves and vent pipe.

davdi

What that means is that my bathroom is just under 7 feet wide. Right now the tub is in a corner with no alcove or enclosure. I'm moving the tub to an opposite wall. That wall is getting replaced, and a matching alcove back is being put up. This leaves the rest of the 7 feet behind the tub is available. I want to maximize this space. Image below shows the layout, and the blue is where the new alcove walls will be.



so the 2" gain would be 1" from each side of the alcove.

BUT, I didn't think about the valve difficulties. I may do 2X4s on the front, and just 2X3s on the back. The wall is getting cement board and then tile.

Rethink that; you want your wall strong enough so it doesn't flex if you slip in the shower and crack your tile.

I'd make a slim wall there, to optimize space. Several ways to do this.

Nate, this is getting clearer. The valves will be in the RHS wall? or the new LHS wall that encloses the alcove?

david

You have My permission!
Space studs 12" on center and block 1/2 way up the wall

Valves and such will be on the RH wall. Left wall will contain no venting, etc.

I'll have to look at my venting and valve scheme to see if I can use 2X3s on the RH wall.

what membrane will you be using? Shower wall membrane.

To save space, you can get 1/4" cement board CBU material, like 1/4" Hardi. Also, you can shave off a 1/2" from the existing studs. Then, when the wall tiles are laid, their top (surface) becomes flush with the drywall. You need a J strip to hold the drywall edge in, and to accommodate the always present but slight difference in "height" positioning. Looks cool.

At the LHS, I guess you are going to have shelves for towels, linens, soaps and "products" in general.

If so, I'd build that LHS "wall" with a rectangle of tempered glass going from the tub up to the ceiling.

david

Membrane? Hadn't crossed my mind. Need one in a tub? Suggestions? Why?
I guess I was originally thinking: Studs / Vapor Barrier/ Cement Board / Tile. Is this not acceptable? (Or, is there a better way?)

There are no existing studs on the right side. What was there was 2 pieces of 2X2 (Actually old 2X4 cut in half) that had 1/8" paneling nailed to them. This created the wall for the bathroom and closet that is on the other side. I will be putting in a proper wall now, so I have stud depth options.

I already bought 1/2" Cement board. I guess I didn't see how it would save wall thickness, since the tub determines the width between the insides of the Right and left walls, really.

Tempered glass IS a new and interesting idea for the LH wall, but I suppose I'd still have to make a little wall to support the tub. We did plan on some sort of shelving between the LH of the alcove and the bathroom wall, just as you said.

A vapor barrier behind the cbu lapping over the tiling flange is all that is required. Some people prefer a surface membrane to waterproof the wall instead of just making it water resistant. There are lots of choices here, I prefer Kerdi from www.schluter.com, but Noble makes some good stuff, along with Latticrete, and there are paint on waterproofing membranes like RedGard from Custom Building Products that work as well. Grout and tile are not waterproof, very water resistant, but some will get through. Then, it gets into the cbu. If it doesn't get a chance to dry out in between showers, it gets to the vapor barrier, which when done correctly, gets back into the tub. Blocking it at the surface under the tile is an other option. Don't do both.

A glass panel at the end sitting on a knee wall would be thinner than a true stud wall, at least on the upper area. Depending on what you were going to do, that is a possibility. Another choice would be a glass block - the thinner ones are 3" thick, I think, which would be thinner than a wall with sheathing and tile. If, when you build the wall, you make the shelves in the storage area rigid rather than moveable (or at least a couple of them), you'd go a long way to stabilize that wall. Otherwise, I'd still prefer to see a thicker one to help stabilize the tile.

HardieBacker states that you can use 1/4" wallboard on the walls, but most pros much prefer the 1/2" on a wall for the extra margin. I don't think any of the other brands suggest anything thinner than 1/2". 1/4" is all you ever need on a floor, although you can go thicker to help match heights.

no shower in the tub? Then no need for shower wall membrane.

If there is a shower head over the tub, you need at least plastic under the CBU. There is another thread going on right now about wall prep.

A little support under the tub is essential. It can be inside the tub, with nothing to speak of sticking out. Then, a glass panel would be siliconed onto the tub edge, not onto the edge of the support structure.


david