Posted By Kelsey Crisp on 30 Aug 2010 08:25 PM 

If you use the green board, water will not bother it even if it does get wet.

Posted By Kowboy on 30 Aug 2010 09:22 PM

Posted By Kelsey Crisp on 30 Aug 2010 08:25 PM 

If you use the green board, water will not bother it even if it does get wet.

Kelsey:

Not according to syndicated "Ask the Builder" columnist Tim Carter:

"For example, I have had great success using this green board drywall behind sinks, toilets and on walls with ceramic tile back splashes. But I have had horrific failures when I have used it behind ceramic tile in tub and shower areas. Water and water vapor can readily pass through ceramic tile grout and cause the paper facing of the drywall to disintegrate. Water-resistant drywall is simply not recommended for areas that are subject to constant moisture."

Joe

Once again the topic gets twisted so you will have something to post

Joe, if you read the post, I was talking about the area outside the shower, Norm was talking cover with Solid Surface,  and green board "is"  ok for an occasional splash.  I grew up installing greenboard behind showers in the 70's, laying ceramic tile over it. Now 30 yeras later, i am replacing countertops in some of those homes my family built and have torn out and replaced the very bathrooms I installed years ago, for solid surface surrounds. The problems I have run into is the floor around the tub, not the green board.
I have torn out many showers to find ceramic over plain drywall, all looked great, except around the faucets, the mold in the grout. If ceramic is laid right, which I guess he couldn't do since he admitted more than one failure, it holds up pretty good.

I'm not sure why you would post an argumentative reply, oh yes I do, it seems to be the nature of everything that comes after the words, Joe, Loosedeckcannon, Trebuchet, Kowboy.

It's amazing how so many who could not make it in their trade, suddenly overnight can become a consultant or expert in that field.


Geez...

I think the DensGuard or Denshield by another manufacturer is probably the best thing going as a substrate for any application. Getting off the subject a bit I always use cement backer board for tile installations along with a product from Laticrete called Hydroban. Hydroban is a liquid waterproofing membrane that can be water tested after 24 hours. I've found that the cement backer boards, although impervious to damage from water, do actually absorb water causing tile grout to grow mold, especially on a mosaic tile shower floor.

I have replaced tiled showers than were only five years old, most of them failed because the tile guys screwed  cement backer board to the inside of the curb through the shower pan liner. The correct way to do a curb on a tile application is to nail paper backed lathe on the outside of the curb, bend it over into the inside of the curb, and when the mortar bed is installed it will hold it in place.

Back to the original post, I think I will probably use Denshield as the substrate for the tub surround, extending beyond the tub approx. 3 inches, mostly because I don't like the idea of green board next to the outside of the tub, it's moisture resistant, not moisture proof.

One other tip, you can paint a bathroom with two coats of oil based primer (kilz) before applying a latex top coat to make it more moisture resistant.

Posted By Peter Carpenter on 31 Aug 2010 05:48 PM
I have spoken about this before on another thread, it doesn't matter what material you use behing the tiles or ss so long as it is approved in your area and if you water proof it. We use Water-based polyurethane-acrylic waterproofing membrane developed for high performance under-tile waterproofing on the walls and floors with a Coving Bandage applied on cracks greater than 6mm. Applied with a fluted roller, it is used as a reinforcement for membranes. I am doing a bathroom toilet and laundry soon so I will post some pics.