Fix uneven tile

Question

My first tile job has not gone according to plan. This was my previous post on preparing the underlayment for the small mosaic tile.

I pulled up the OSB and replaced, re-secured the subfloor, replaced the tar paper, installed 1/4" underlayment and 1/4" CMB.

The problem (one of them anyway) was that using the thinset to join the different CMB cuts cause the floor to be be about 1/8-1/4" un-level the length of the floor. This is very noticeable when walking on it.

Here's a few photos of the installation (be kind!).

What would be the fastest way to address this rather than taking up the entire floor again (possibly buying more tile depending on salvage) and applying self-leveling cement? I'm really worried about the transition if I add any more height to the floor as it's just even the way it is now.

Is it possible to bring up just the most affected areas and apply a thicker cost of thinset? Or, is that just begging for different problems?

Answer 1

You have to take it out or live with it.

1. You don't thinset between the cement board until you are tiling. This ensures that you will have a chance to flatten things out.

2. So knock out tile and all thinset, including the stuff between the cement board. You should be able to get this with a hammer and chisel pretty easy.

3. The retile, filing in the gaps during the tiling process. If they don't get all the way filled in perfectly, shit happens.

4. Tile again. You did a really good job on the actual tile work. Thinset maybe a little too much or maybe you need to clean your joints faster but a great first tile job.

What you learned is that 80% of tiling is prep work - you had a small hiccup here. That is why on those reno shows they are dumbasses acting like they are great at tiling showers when the contractor did all the prep for them.

Answer 2

I would take a more selective approach here. I really only see a few tiles that would be problematic. If there are more than that then take DMoore's advice.

I'd take out the tile in small areas (6 to 12 inches in diameter), then assess the situation. Chances are you can grind the substrate to level and reinstall tile (using a straightedge or flat panel as a leveler).

Answer 3

It looks like you did a good job of keeping the lines straight. I do not see the uneven line on my phone. When I use small tile I usually float the floor with thinset to make sure the slope to the drain is good. It sounds like the thinset has setup since you are walking on it. It would be difficult to repair without pulling up several rows. If you are very unhappy it may be best to bite the bullet and pull the tile. Thin set ridges are not hard to grind flat with a angle grinder and a masonry disk. A wide chisel can be used also but will take longer. Once the ridges are out mix some thinset and trowel a thin layer making sure to maintain the slope to the drain. You may be able to work the ridge down with just a couple of rows but this will be very difficult. If you do refloat the floor once set I usually check with water to make sure there there are no low spots that hold water prior to putting the tile down. Small tile is the toughest to do a really good job with in my opinion because there is no room to make up any errors in the base and with the short span and tighter grout lines it can be tough to get it perfect.