I have installed cement backerboard around the bath area. We are planning to install 8x12 tiles. I have noticed that the walls are not perfectly flat. When I place a tile to certain spots on the wall (but not all) it rocks. The article on this site suggested applying a layer of thincoat to the walls. Can I do that to "flatten" the walls? If so how do I ensure that is flat? Or should I remove all the backer board (ouch) and repair the studs.
one section the wall bows out (1/4" max) can I "sand" or remove that area to flattens it? The other wall bows in about 1/8" - can I use thincoat to build up?
Re: flat walls
A 1/4" is a bit of play to mess with...but it might be do-able with the thinset. I guess I'd use a 3/8" V-notched trowel and where the wall bumps out..knock down the ridges from the trowel marks to where it'd make the tile lay flat/even to the adjoining tiles. I'd also back butter the tiles with a thin smooth coat of thinset for better adhesion.
Its really your call because I can't see it from where I'm sitting.
USing my method in your mind as you play with the tile on the wall you decide whether or not you're capable of making that work or not.
Next tile pay attention when you put up the backerboard or your fired :D
And youy better have put up a vapor barrier behind the backboard or don't come to work in the morning :rolleyes:
Re: flat walls
You can put a ¼" strip on each side, aply thinset, then drag a staight edge down the wall riding on the ¼" strips. It's much the same as leveling concrete.