Need advice on installing tub faucets

[mntentman]

Hi,

We are putting new tile on our tub surround. We have the cement board installed and will soon do the tiling. I need to replace the bath hardware, which I thought would be relatively straightforward, and maybe it is. But a lot of the hardware I'm looking at is more than the basic stuff we had, with temp controls, anti-scald, etc., which appears to require more work -- maybe behind the drywall -- than just basicaly slipping the new hardware on. But I'm not sure. I want something simple to install. Here is a photo what is on there now. Will I need to remove this and cut a larger hole in the board to get behind it, or is there a fixture that won't require that? I'm looking at HD. Thanks much.

[jadnashua]

Tub/shower valves can be bought with the rough-in valve and your choice of trim (but the big box stores often sell them together as a set). Even within brands, not all trim will fit all valves, so you'll need to remove what's there and start over. Assuming this is also used as a shower, codes require anti-scald technology in the valve. If it is a tub only, that's not required, but because most are used for a shower too, anti-scald is often in most of them.

There are two ways to get anti-scald (and some contain both): thermstatically controlled or pressure balanced. The objective is to keep the shower from both getting too hot (with a limit control) and to keep the mixture from getting too hot if someone say flushes a toilet, lowering the cold in the mix thus raising the temperature.

The pros here like Delta. They make both, so it's your choice. Personally, I like being able to set the temperature at your ideal, and never having to change it bacause most of them have a separate volume control. most pressure balanced valves turn on full force starting at cold and the further you turn it, the warmer it gets up to the limit stop. Your old one probably didn't have a limit stop.

[mntentman]

Thanks much, Jim. Yes, this is a tub/shower.

So my questions are these, then, which will show you how little I know about this stuff...

1) I am now assuming I will need to get behind the new backer board. Am I better off removing it (it is ony screwed in now, no taping yet) or can this work be accomplished by making a bigger hole in the board.

2) I should have asked this question first, and it may answer my previous one. If I need to replace whole assembly, will that require removing hardware between the section of pipe under this and above it? Or am I able to stop short of needing to do that? (Not sure how hard that is.)

Now I know why all I am seeing are anti-scald setups, since you say they are now required. I have never felt I had a problem without one, but so it goes.

Thanks again.

[Terry]

What you have is a non balanced Moen.

I would remove the board before it it taped, and replace with a balanced valve, there will never be a better time.

[mntentman]

Thanks. Will that involve getting a plumbr in here to solder a new valve in?

[hj]

1. Remove the wallboard.
2. Call the plumber.
3. Purchase a new valve or tell the plumber which one to bring.

[jadnashua]

If you aren't comfortable soldering in an area that will be covered up with timeconsuming and maybe expensive tile; this is the time for a pro to install a new valve for you.

You will need to tell him exactly what will be going on the wall so he can set the valve in the proper position so the trim will fit. The depth is important.

Most valves come with a plaster guard that shows the min/max depth location. Most people find it it is sticking out too far, it looks funny (I think it looks ugly), but you don't want it too deep in the wall and have to go find an extension kit so you can screw down the trim, either. that's why knowing the thickness of what's going on the wall is important. Maybe have a scrap of the cbu and tile on hand. Then you can put the trim up against it and see how it will look.

I don't see a vapor barrier behind the cbu, either. It's good to put roofing felt or plastic there, lapped over the tiling flange of the tub up on the studs before installing the cbu. The tile nor grout are waterproof, and moisture can get behind. Best to keep it off of the wood.

[mntentman]

Thanks. There is a vapor barrier behind the cement board and roofing felt in strips on ther studs so that the cement board meets up correctly with the drywall outside the tub. The barrier does extend down over the tub flange.