Designing Kitchens and Bathrooms - Tiling Countertops-Newbie needs a mentor.

My sis has 2 projects. The first is a old kitchen cabinet that was removed when she had new kitchen cabinets installed. The second is an antique dresser that we removed the top from after a previous guy she had working for her butchered the top. The old cabinet is in good shape, the old countertop has been removed. She has moved it out to the back porch where she's going to use the bottom for storage and the top for making bedding plants for her garden. The porch cabinet was our practice cabinet. We decided to put a new top on it as practice before tackling the dresser. We bought a tiling book from HD; the job looked simple enough. NOT! I cut a piece of 3/4" plywood, fastened it down to the old cabinet, tried the tiles on it and had some uneveness across the top surface. By unevness I mean the tiles at the seams are not level, some stick up a little, some go down a little, some are perfect. Not to worry I'm thinking, the mortar bed will make up for it. Next, I cut the hardiebacker board, laid a mortar bed on the plywood, troweled it out, used the notch side of the trowel, laid the backerboard on the mortar and screwed it down. The uneveness got a little worse. hmm.. After the mortar set uo a couple days we installed the tiles which are 12" x 12" x3/8" thick travertine. I put down a nice motar bed about 3/8" thick, set the tiles in place, pushed them down into the mortar and so on. She didn't want any spacing in between the tiles which I objected to but she says that's the rage now. Guess what- the tiles are still uneven. As you run your hand over the top, at some seams where the tiles come together, there is as much as 1/16" height difference. Well big deal, it's just an old cabinet that's now a quasi workbench. BTW- I grouted it, that was easy.

So a few weeks later I move on to the dresser. I install a 3/4" plywood top, lay out the tile [12" x 12" x 1/4" thick granite tiles this time, she wants the same thing, no spacing]. Same business, uneven across the top. Some tiles are actually wobbly like they're high in the middle. I scraped down the plywood top and got some slivers off but it's still uneven. So I lay down a motar bed that's thicker than the last job, lay down the hardiebacker board, then screw it down. I test the surface with the tiles again and I have the same uneveness. Before I put down the tiles I need to figure out what I'm doing wrong. I want the dresser top to be as perfect as possible. What am I missing? When you trowel out the motar, how do you get an even thickness?

Hmmmmm

It does sound like you did everything by the book but I would suggest laying a level across the hardibacker board to make sure it is indeed flat. Look for any caps between the level and the substrate. If you see spaces, that indicates that the substrate is not flat.

If this test shows the plywood/CBU is flat, then your tiling job is your problem.

Make sure the mortar bed is evenly troweled. When you lay your tile, set the tile in the bed but do not twist it back and forth to set it in. Just tap on the tile with a block and rubber mallet to set the tile down. Use a small tile level device to check height differences with your next tile. This level is only a couple inches wide and has legs to rest on two ajoining tiles.

Also, natural stone may not be perfectly flat as well, be sure to check that with a straight edge or level.

Good luck!

HI Hot:

Thanks for your reply. I already know that the substrate is not flat and level over the entire surface [apprx. 56" by 19"]. The problem I'm having is overcoming that deficiency. When I trowel on the mortar, I can tell it's not even. What's the secret to getting it even? No matter how I use the trowel, I can't seem to get the mortar bed the exact same thickness all across the surface. What is the secret? Start with a perfect substrate? Shim the tiles? I have already installed the hardiebacker board on the dresser top and it's not flat/level all the way across. Is there a way to sand it down?