How thick should I build a section of wall to hold shower and laundry plumbing?

[Canada_DIY_Plumber]

I'm redoing my bathroom to add a washer/dryer (X marks the spot). I've had to do a full gut since the sewer was under the slab and I needed to jackhammer down to it to put in a dedicated drain for the washing machine. I was tempted to just run the clothes washer into the drain currently servicing the bathtub but that's only 1.5" and part of a wet vent system. While I was at it, I moved the the bathtub drain onto the new 2" branch drain and I will dry vent it.

There is a little 4" thick wall that juts out and currently holds the plumbing for the shower valve. When I am done, that wall will also now hold the plumbing for the laundry (supply, drain, vent) and also a vent for the shower. My plan had been to just double that up with another set of 2*4s so I'd end up with a wall about 8" thick and lots of room for all the pipes.

In the latest hiccup, the 5' bathtub that came out was more like 4'11.5" and the new 5' tub is exactly 5; and it will not fit. As a result, I need to tear that wall down and rebuild it. (Sure becoming a lot of work for adding a washing machine...)

That opens up two new questions:
1) My tub is exactly 5'. How wide should I make the opening? 5'1" or 5' 1/2" and then I can use some shims when attaching to the walls? I will be tiling the surround.
2) How thick should I make the wall to hold the laundry supply/vent/drain on one side and the shower supply and vent on the other? I'm thinking I may be able to use a 2*6 instead of two 2*4s. I will be using PEX-B for my supply lines.

 

[wwhitney]

1) 5' would be fine if you can get the tub in. You could build the circled wall after placing the tub. Or you could go 5' 1/8", 5' 1/4", whatever you need to place the tub.

The tub should have an integral flange, and best practice is to fur out all 3 walls as required for your tile substrate to hang down clear over the flange. Since the wall at the bottom of the picture extends beyond the tub, probably best to position the tub tight to that wall, to minimize the required shimming there.

2) You need to do a paper layout for the plumbing in the wall. If you can avoid crossing any DWV pipes and still leave room for the shower valve , you could do it in 2x4. But that's likely not practical. 2x6 should be sufficient, just confirm the layout before constructing the wall. If space is really tight, you can go with a non-standard thickness and rip the framing to the required width.

Cheers, Wayne

 

[Sponsor]

 

[Canada_DIY_Plumber]

1) 5' would be fine if you can get the tub in. You could build the circled wall after placing the tub. Or you could go 5' 1/8", 5' 1/4", whatever you need to place the tub.

The tub should have an integral flange, and best practice is to fur out all 3 walls as required for your tile substrate to hang down clear over the flange. Since the wall at the bottom of the picture extends beyond the tub, probably best to position the tub tight to that wall, to minimize the required shimming there.

2) You need to do a paper layout for the plumbing in the wall. If you can avoid crossing any DWV pipes and still leave room for the shower valve , you could do it in 2x4. But that's likely not practical. 2x6 should be sufficient, just confirm the layout before constructing the wall. If space is really tight, you can go with a non-standard thickness and rip the framing to the required width.

Cheers, Wayne

Thanks Wayne!

 

[Jeff H Young]

5 ft 1/4 inch would be what I'd build.
Depending on site conditions and how it lays out 2x4 probably too tight , but you can fir as needed or try 2 x6 and likely not need to fir it more