I am framing in a new shower stall. There are no exterior walls to this shower. I am installing solid surface Swanstone over 1/2 inch cement board attached to wood studs. I was thinking I would not need a moisture barrier under these conditions. Much of the CBU is up. Any comments are welcome.

Hi Murztwins

Many different schools of thought here.

Best case would be to install a 15LB felt paper (tar paper) over the studs BEFORE installing the cement board.

Next best would be to roll a waterproof membrane over the entire surface of the cement board once it is installed, but with swanstone walls I don't think that is correct procedure!

Others would say that with no outside walls and no STEAM SHOWER UNIT being installed you don't even need a vapor barrier (I am not one of those people).

In this case, I would have to tell you to contact the manufacturer of the product for a final say on this.

I do know that swanstone will require that you roll a water or oil based primer over the cement board before installing the swanstone walls. This should be clearly stated in the instructions under USE CEMENT BOARD... ;)

Back to you...

Mark

PS: DO NOT install a double vapor barrier by installing insulation on inside walls with vapor barrier toward bathroom, OK?

Swanstone does not require a vapor barrier but it is so cheap do do just lay down 15lbs felt or visqueen. However, I never have and have had no issues. He biggest failure installing a Swanstone is forgetting to grout the base in with Structolite or dry mixed drywall compound or even flooring thinset. A slight flex can happen to the floor of the base and that will result is noise and eventual leaks at the drain. Didn't you get a booklet like this one? http://www.swanstone.com/images/link_installation/BK-326072.pdf