Bathroom remodel, how to install new tub with MINIMAL access behind?

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Old 10-25-12, 11:24 PM
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Bathroom remodel, how to install new tub with MINIMAL access behind?

Hi folks,

Completely gutted my guest bath down to studs because it was old, the tub was yellow and had brass fixtures, the popcorn ceiling was flaking off into the floor constantly. In addition, the previous owner had tiled the floor, removed the tile but not the Ditra and thinset, then nailed down 1/4" concrete backer board so it was unlevel. I removed everything down to the 3/4" plywood over the joists, installed an additional layer of 3/8" plywood over the original, then put down 1/4" of mortar and a 1/4" of concrete backerboard in preparation for tile.

That leads me to my current question. I have the backerboard down under where my new tub will go. I have the new tub in the bathroom currently but I do not have it installed (it is standing on it's side) I'm wondering how I will get the drain to match up to the current drain without having "full" access to the back of the tub? I was able to cut a hole in the vanity and drywall in the adjacent bathroom and give myself about a 6X6 hole to access the shutoff valves I placed (there were none before). I have several questions regarding the tub install:

1. Do I install my drain to the trap in the floor first, then scoot the tub into place and make my connections to the overflow and floor drain?

2. Do I need to put down concrete under my tub before I install it? (it is an acrylic tub)

3. I've seen videos where some people have placed 1/4" strips on the studs behind the cement backerboard in order to prevent the backerboard from "kicking out" at the bottom when placed over the lip of the tub. Is this standard practice? By the way, I'm not installing a tub surround, I will be tiling one myself.

Here are some photos of what I'm working with. Any help would be greatly appreciated.
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Old 10-26-12, 04:38 AM
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Welcome aboard...

You will want to hook the drain assembly to the tub first and lower it into the p-trap. Probably want an extension of some sort so that you can make the final hookup above grade (otherwise, hole in ceiling below to access).

You will need a ledger board on the walls to set the tub level.

Don't forget to add nail plates to protect all those copper lines from accidental puncture.

Looks like you have done good so far. I would have put down 1/2" instead of 3/8" and I would have held off until I had the tub set. If you need to adjust the drain location, would have been easier prior to finishing the floor. And have fun with that horizontal vent stack conveniently located in line with where your new valve rough-in probably should have been.

Keep us posted
 
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Old 10-26-12, 05:26 AM
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To further Czizzi's comments, You may have to make ceiling repairs, but you will find that access from below will make this install much easier as far as the drain goes. Yes, after you install the ledgers, you will need to put down several dollops of thinset around the base (not a solid layer, as it has to squish out), then set the tub in it.

Since you are going to tile, I wouldn't bother with the strips on the studs. Bring your cbu down to the top of the lip of the tub and stop it there. Your tile can jump that short distance, and it will also prevent any possible wicking in the cbu.

You may dodge the bullet on the vent since this a tub install, but your shower stand pipe will need careful routing so as not to be interfered with on that horizontal pipe.
 
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Old 10-26-12, 07:25 AM
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So you have a hole in the ceiling now? Thats how your accessing?

Will there be a permanent hatch?

Valves in the wall for the tub???? Not a good idea imo.


If the drain for the tub does not line up, you will need to swing the trap. Is it hard trapped? Most common is an LA trap.

Let us know.
 
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Old 10-26-12, 03:32 PM
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czizzi -

I would have put down 1/2 but I also have a radiant heat mat to put down under my tile, so I was trying to save height where I could without raising the transition from the hallway into the bathroom significantly. I planned on placing a ledger board, It's usually 1" below where you dry fit, correct?

chandler -

access from below is pretty much a big NO. It is in the center of my living room. The way this house was designed pretty much set up the bathrooms for catastrophic failure if there were a simple leak. Also, there were no shutoff valves to the showers at all, or access to the back. I'm going to have to create some better access to the back of this current shower when I remodel the master bath.

What you see in the second picture is a small access hole to my shutoffs I cut in the side of my vanity in the master bath. I have to remove the drawers to get to it.

I like the idea of stopping the cbu at the top of the tub to prevent wicking, and I can just tile down over it and silicone the seam. Do you suggest putting silicone on my vapor barrier on the lip of the tub?

It doesn't look like it but the walls are actually 2x6's so there's more room there than it looks like. The other line feeding the shower head before didnt have any problem going through there.

Lawrosa-

No there is no access from the ceiling below and the trap is hard trapped so if I have to swivel It i'll have a lot more work to do. My rough measurements from the wall show it being centered at 16 inches so I think I'll be ok.
 
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Old 10-26-12, 04:45 PM
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Do you suggest putting silicone on my vapor barrier on the lip of the tub?
I guess there are as many variations as there are tile setters. I do remodeling, so most of mine is from what I have learned over the years, advancing techniques as I go. I like to bring my vapor barrier all the way into the tub, cutting it off over the lip letting it hang under the cbu and over the tub lip. Tile will cover it all and it has a free flow into the tub. I also, if I can get a good tile fit, don't silicone the lip to tile connection, leaving a 1/8" crack all the way around. My theory is, if any moisture should penetrate, it can migrate back into the tub via the vapor barrier without obstruction. Likelihood is remote, but it's there. Water won't wick up the back of the tile and lip of the tub, and you don't have the constant problem of removing moldy silicone from that area and replacing it just to see the mold grow again. Others will have different ideas, so hang in there for their comments, too.
 
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