The bathroom I’m remodeling has a back tub wall of masonry block. I have ripped all the old tile off and still need to remove the mortar base that was underneath the tile, which showed some signs of water damage.
Do I tile right over the masonry or do I need to install backer board over the masonry? The new tub sits right against the masonry wall, so I can’t have very thick furring (if necessary). I’m a bit concerned about condensation from this cold exterior wall. I don’t know if there is any insulation.
Paul
Replies
Cement backer board is masonary, as long as the surface is smoth enough to lay the tile your good to go. If it's not then float it level with a skim coat. As far as the surface transmitting temp- that's another issue. when it comes to the masonary to stop, it's great at wind/sometimes.
paul
I also would be concerned about a cold masonary wall.
If I were you I'd check into the amt of cold air that infiltrates the area before I did anything.
A picture might be worthy in your post.
Seems to be more to this than I can comment on without pics and more of a description to comment.
Be well
andy
The secret of Zen in two words is, "Not always so"!
When we meet, we say, Namaste'..it means..
http://CLIFFORDRENOVATIONS.COM
Andy,
I was mistaken about the exterior wall. A room was added on behind this wall making it an interior wall.
I still have the problem of preparing the substrate. Currently, there is about 9/16 inch of mortar over a wall made from solid masonry block. There is lots of residue from the tile mastic left. From the tub edge up about a foot, I have chipped away the mortar to the surface of the block. It is getting fairly difficult to remove with hammer and chisel.
Should I use a demolition hammer to remove the rest of the mortar? If I take all the mortar off, I still have to attach a substrate to the masonry wall to get my tile beyond the tub lip, not to mention having a clean substrate to tile over. How would I attach the substrate? Backer board with thinset to hold it to the wall? Or some kind of mechanical faster, like a masonry anchor? Or a mechanical fastener that epoxies into the masonry?
If I choose to leave the remaining mortar on the wall, I need to install some furring in the area in which I have removed mortar, just to have some support for backer board in this area. This puts me out 9/16 inch beyond the tub lip, even before backer board and tile. I do have the option of moving the tub away from the wall a bit, I think. I would have to check the waste pipe in the crawlspace.
I would like to use Dens-shield, if possible. I used it in my own house and it was a joy to work with. Otherwise its Durock or Hardibacker.
Sorry, I don't own a digital camera Andy. Any advice would be appreciated.
I forgot to mention, in the middle of this back wall is an area of about 3' x 4' where there was a window. Now there is mortar over lath board.
Thanks Andy
Paul Somlo
Greeley, CO
paul
If its feasable to you I would use a wide masonary chisel to get the high spots down in order to get the dust at a minimum, after all, its not that huge an area.
I also believe that you can thinset the "Wonderboard" to the wall but use a liquid latex additive rather than water as that makes it a whole lot more sticky. I would trowel the thinset to the wall and additionally I'd butter the back of the "Wonderboard" for total adhesion.
I don't belive using this type of application would require any fasteners at all.
I've used this method to stick `18" heavy tiles (Granite) to shower ceilings and they've never failed on me. I used 2x material to hold the tiles to the ceiling and taken the 2x's down the next day and no, I didnt put a 2x under every tile....I rigged up a support system across the ceiling and used shims to hold them in place snuggly.
You may want to consider something similar for the CBU if you feel its necessary although I doubt you'd need that.
Be well
andyThe secret of Zen in two words is, "Not always so"!
When we meet, we say, Namaste'..it means..
I honor the place in you where the entire universe resides,
I honor the place in you of love, of light, of truth, of peace.
I honor the place within you where if you are in that place in you
and I am in that place in me, there is only one of us.
http://CLIFFORDRENOVATIONS.COM
Since it's an interior wall, you can apply the tile right over. Check with your local tile/masonry folks, there's an mixture you can put right on block, finished block, and both glazed and unglazed clay block to give a substrate that thinset will stick to like glue.
We're about to start in on a remodel that has glazed clay block, and we needed a way to add tile for new showers. Our masonry supplier led us to the new product which lets us skip the step of putting up backer board before the tile (which is saving space in some tight ada-driven dimensioned areas).
As much as I hate it you have to get the grinder out and dress that wall down. Set up a fan in the window??? hopefuly there is a window. You can lay your backer board in thinset and then use some 2xs to jack it against the other wall till it sets. The specs call for fastening it sooooo if that's what your gonna do in addition to a thinset base you can use some tapcons, recess the predrilled holes with a countersink so the heads lay flush.
You will get some leeway with the original wall using a 3/8" notched trowel. Check with a screed board for any high spots and take em down so the baker board gives you a good flat plane.