[sticks41]

I am installing a one piece shower in a new addition. What size hole do I drill for a one piece mixing valve in the shower. They do not state in the directions what hole I should drill

 

[rjniles]

Drill the size of the plaster ring on the valve.

 

[sticks41]

you stated drill the hole the size of the plaster ring? Doesn't the ring stay on the back side of the shower? If I drill the hole that size, the whole ring would go right thru the shower?

 

[rjniles]

The plaster ring should be flush with the finish surface.

 

[Ghostmaker]

Older plumbers normally secure the valve with two by fours in the wall.

Makes life easier when removing bad cartridges in the future.