If it's going to be a wet-area application, like a shower, I wouldn't
recommend it. If it's a counter backsplash in a kitchen, regular tile
adhesive is the way to go. You can't use thin set on sheet rock.
Wet areas such as showers require a water-resistant substrate. Be it
mortar or tile backer. Drywall is NOT an acceptable substrate in those
Also, thinset has been used as a setting agent for installing tile on
drywall since it's inception.
Thinset and tile has been installed on sheetrock since it's inception,
very common throughout the 70's. Grout when properly applied and sealed
has 3-5% penetration so water will never reach the masonry backing or
sheetrock. I like miracle sealants products
http://www.miraclesealants.com/ Just remember to reapply annually or
bi-annually. For what it is worth I would use a masonry substrate if it
were my shower/tub.
There comes a time in the affairs of man when he must take the bull by
the tail and face the situation. -- WCF
To clarify, in wet areas DO NOT install ceramic tiles over drywall, use
cement board as a substrate.
"If it's going to be a wet-area application, like a shower, I wouldn't
recommend it" - I wouldn't recommend installing tile over drywall.
In a kitchen backsplash, installing tile over drywall using a mastic
adhesive is o.k.
I evidently didn't make that clear enough.
All that's been said, often in a very belligerent fashion, is well
understood. So I'll tell the other side of it. Where I say I do it,
and have done it for years. With an I.Q. over 50.
Water should never get behind the tile. Ever. So the first part of
the tiling process is to eliminate the main reason for it happening.
At the beginning, I use Styrofoam to fully insulate the wall. No point
in having it chilled from outside and serving as a condensate site.
With different thicknesses, and cuts made to cause it to be a snug fit,
I arrange the insulation so that there are no air spaces in common.
For any small spaces that are not practical to fill, I use Great Stuff
foam insulation, cutting any extra with a hacksaw blade.
The Styrofoam comes to the exact edge of the stud, with no difference.
Then I put Greenboard in place. It's moisture resistant, but there
should be no water exposure, at all. An important element to that is a
well-leveled and secure tub or shower unit. I accomplish that by
bedding it into thinset. When a person takes a shower, the flooring of
the shower should be rock-solid, as should the sides.
First tile is most important. I run a fairly generous bead of pure, white
unpaintable silicone along the edge of the unit where the tile will go.Then
I run a bead along the mating edge of the tile, and a denerous squiggle
of it on the back. I put that tile onto the Greenboard about a half inch
from its final spot, then firmly push it into place, and any extra silicone
quickly removed by finger and put on the back of the next tile. And
I select a tile that will match the silicone. Often, I will use a style
Arctic Ice. I make the joints small, the silicone transitions are minimal. I
usually use 12" tiles.
I've been doing it this way for over 20 years, and have never had any
mildew problems, no wetness problems. Far as I'm concerned, the
main problem with tile is not the tile, but the grout. In these days, I see
no use for it. In the first tile job I did this way, I used a yellow tile
siliconed space of about an eighth inch, and after ten years it was still
Just wanted to give the other side of the story.
I've never seen a bathroom tile wall with 12 inch tile, but if you
Also, I am somewhat concerned about mold in your walls. Many of the
mold pictures I've seen show mold growing on the styrofoam insulation.
On Wed, 10 Dec 2003 03:06:31 -0500, "Michael Baugh"
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