amodoko

Hi guys, I'm about to tile my bathtub surround and have some questions regarding moisture barriers. I already have the 1/2 durock cement board and 6 mil plastic sheeting. Before I put up the plastic sheeting on the studs, I wanted to double check to see what people thought was a better moisture barrier... Redgard painted directly onto the cement board or the 6 mil heavy duty plastic sheeting attached to the studs. If you pick one over the other, can you tell me why? Is there a difference in how well each one will protect from long term moisture problems? It would be nice to hear the pros/cons to Redgard vs the plastic sheeting.

I'm debating whether or not I should just go buy some Redgard and leave my plastic sheeting for another purpose. But if they both offer the same long term protection, then I'm happy just sticking with my plastic sheeting since it will save me a trip to the store and I am more familiar with that as a moisture barrier.

nealtw

Red gaurd is used to protect the board from getting wet. Your poly is only required for the insulation and is not needed anywhere else. I can't think of any reason why you couldn't do both. I would buy the Red Gaurd.

amodoko

Yeah, originally I thought about doing both RedGard and plastic sheeting, but after doing a bit of research it seems that this is not safe. Apparently, if you do both of these moisture barrier methods, vapor can get trapped between the cement board and the plastic, and then it has trouble escaping which can cause issues. I'm not an expert at all, but that was just what I have heard.

Oh, and I don't know if this makes a different, the tub's long side will be up against an exterior wall.

inspectorD

Good research!
Redguard is a moisture barrier,( keeps the water in the shower from getting to the interior)
I would eliminate the plastic, you do not need it to trap any moisture or vapor in the wall. Don't forget you also screw throught he plastic to install the cement board. And not that it will never dry out, it takes longer after it does get wet. I am also not a fan of plastic. I have done to many remodels with damage in the walls that have a plastic vapor barrier. Kraft paper is a much better product,for future reference, In my opinion.

__________________
Just My
Made in the

amodoko

thanks for the message So you think I should not use either plastic sheeting or Red Gard and have no barrier? Or do you think I should use only Red Gard?

nealtw

The short answer: just use redgaurd.