What size hole for my Delta Shower valve should I cut out in exterior wall?

[BRrenovator]

Hello,

I have a Delta R10000-PX Multichoice Universal Rough Valve Body. I'm using the Schluter Kerdi materials in my bathroom. I'm not sure whether I should use the Kerdi Seal MV for the shower valve - KMSMV235/114. It's a 4 1/2" seal. Neither Schluter or Delta would tell me what size hole to cut in the exterior wall (1/2" Kerdi board).

The exterior wall in this shower stall will be tiled? What size hole should I cut in the exterior wall? Should I use this seal? Why or why not?

https://youtu.be/Ri0jru_o4E0
See video at 4:39 to 4:55 mark

Thanks much,

 

[frodo]

how big is the trim face plate? hole needs to be smaller than the trim plate

 

[johnjh2o]

There should be a plastic cover that came with the valve body which is the size the cut out should be.

 

[Matt30]

If you don't have that plastic cover, just remember the hole must be smaller than the trim plate but you must have access to the holes to screw the trim plate into the valve body

 

[journeyman]

I usually just use a 3 inch hole saw it will give you the room you need

 

[KULTULZ]

Where is the mud ring that came with the kit?

If you are CDO (correct alphabetical order) like myself , order a replacement mud ring for exact hole size.

 

[BRrenovator]

I usually just use a 3 inch hole saw it will give you the room you need

The Kerdi mixing valve seal is 4 1/2" round. The plastic guard that came with the valve is square.

I wanted to use the Kerdi seal and caulk around the trimplate. I was thinking I would use the Kerdi seal hole as a template for the hole in the Kerdi board. I'll check to see if it's smaller than the trimplate. If I don't use the Kerdi seal, do I just use silicon caulk around the trimplate on the finished wall? What's the best practice?

Thanks much

 

[Matt30]

The trim plate should have a foam gasket on the back. No silicone required.

 

[BRrenovator]

The trim plate should have a foam gasket on the back. No silicone required.

There is a gasket that goes over the valve/cartridge, and then there is a styrofoam ring on the outer edge of the trimplate. Since the hole in the wall will be larger than the hole for the valve/cartridge, how is the water prevented from getting behind the finished wall?

 

[Matt30]

You answered your own question. The gasket on the outer edge of the trim plate