We have just install a new bathroom in the basement. Do I apply Redgard directly on the new purple drywall (unpainted) in the shower or do I apply a drywall primer first?

I just install a new bathroom in the basement. Do I apply Redgard directly on the purple drywall (unpainted) in the shower or do I apply a drywall primer first?

David,

Several things:

1. Moisture resistant wall board should not be used in wet areas, unless you install a waterproofing membrane that will work over it.

2. Redguard is not intended for application over wallboard whether it's a dry or wet area.



Since the MR board is up, you can continue by installing Kerdi Membrane. Kerdi will work great over wall board, you install it using a good quality unmodified thin set. Kerdi is part of a superior system that also includes the Kerdi Drain when the floor is tiled too. Is your shower floor getting tiles, or is it a pre-fab fiberglass unit?

Please explain your project from the ground up, you may have made another error.

Jaz