I agree. I've done quite a few Kerdi Showers, including several steam showers, and I've yet to use any kind of valve seal.

Thank you for the reassurance, Jeffrow,

The face plates did come with strips of foam, but our tile man ripped them out saying they only become a source or mildew as they fill up with wet debris. Does that make sense to you?

I don't see how sealing the valve with Kerdi will affect laying the tile. All of the Kerdi behind the valve plate doesn't necessarily have to be covered with tile if that's the guy's objection. I use Kerdi-Fix or equivalent to seal the membrane to the valve.

In regular showers I don't seal the Kerdi to the the valve. It's really not required and doesn't improve things water-wise.

In steam showers I do.

I never caulk the escutcheon or valve cover plate to the tile. If for some reason you wanted to, don't caulk it at the 6 o'clock position. Leave that open for water drainage, just in case.

The foam strips on the back of the escutcheon plates should have been left intact. They prevent water that runs down the valve wall from getting behind the escutcheon plate or valve cover. If they get behind the plate then the water could get into the wall through the valve hole.

More technique than procedure I suppose, but that's how I do things.

Thanks Mongo,

I was hoping you'd field this question. :-)

Oh well, more experience for the next project. I'll replace the missing tack foam with a loop of grey insulation tubing, the fine one, and yes, with a little gap at the bottom for the water to run through.

Mongo:

In a steam shower, when you seal the Kerdi to the valve, are you using Kerdi-Fix to make a watertight seal around the body of the valve?

Does the plaster guard come off or do you glue the Kerdi to it?

I've heard before about leaving the bottom of the escutcheon unsealed, but doesn't that allow steam to penetrate in a steam shower?

1) In a steam shower I want to do the best I can to prevent vapor from getting into the wall through the valve opening. While it depends on the valve, when Kerdi-ing I'll try to slice the Kerdi and adhere it to the valve body with Kerdi-Fix. Neatly as possible, without gunking up the valve or it's threadings, or adjustment screws, or...

2) Plaster Guard, it depends on the valve. Some valve bodies come with a plaster guard that is simply meant to protect the valve during installation. It gets removed during the finishing phase. Other valves have plaster guards that remain in place after the work is complete. Some are hybrid guards/mounting plates.

If I can use the guard to my advantage, I keep it. If it's in the way, then out it goes. It all depends on the end goal, which for me in a steam shower is sealing the opening without compromising the valve. There's often not a "one size fits all" solution. Just detail things as you're able.

3) Unsealed escutcheon. I might not have been clear in my previous post, but I install the escutcheon just like the installation instructions say. In a regular shower the hole in the wall behind the escutcheon can remain open. In a steam shower I seal the opening behind the escutcheon.

All the above is a "my way" type of thing. It's not the only way for sure.

so i am getting ready build my walk in shower and have been doing a lot of research on kerdi stuff. one question I have is, My shower valve has the square plastic plaster guard ( I guess its called). i see where when the seal is put in place they remove the square guard. Question is does this plastic piece get used or is it trash>

It gets trashed. Wall board needs to be cut to it. It is also used to set the depth of rough in plumbing. You may not be able to use a preformed gasket. Depends on the fixture. This is a 10 year old thread. you will get more response starting a new one.