I'm going to tile my bathroom. I'm in the second story, but the surface is concrete. I live in a condo. I'm told you're supposed to use Red Guard. Do you Red Guard after you float, before you tile? Or, before you even start to float?

1 Answer 1


You use Redguard after the floor is prepped. You can do minor floating as in a thin layer of thinset to fill in an area that may have been overlooked while floating the bath floor the first time.

Being its a condo and the floor is concrete, the floor is either poured in place or precast panels set in place. That in mind, I can't see the floors being much out of whack that would make the floors difficult to get right. Worst case with a precast floor, you may have a joint where two precast slabs meet, that would be the most problematic. If there is two distinct levels then there is not enough grinding that will fix it, better to use a self leveling underlayment with their approved primer, the add the Redguard. You can still touch it up a bit with thinset if you feel it is needed.

The larger tile will take a LARGE notched trowel (1/2"X1/2")to set the floor. This itself will automatically build in some give and take. A level floor is good, but you can work with a floor that is all on the same plane. In other words, flat, no high spots, maybe just a little out of level, not much though.

  • so you float first, and then use redguard? I'm not sure if prepping means floating or etching/cleaning. Feb 16, 2015 at 7:25
  • I'm not doing a shower, I'm doing a bathroom. It'll get wet. But not soaked. I'm just confused at the order of operation with the waterproofing and floating. Do I make the bathroom level with self-leveling mortar, and then waterproof and then the thinset for tiling goes over the waterproofing? Or, do I waterproof and then level the whole bathroom using self-leveling mortar. Feb 17, 2015 at 17:05
  • It's a mortar bead of some sort, already. I live in a condo and all I can see for the floor is concrete. The floor is pretty bad out of level. I'm thinking about using a grinder on the concrete to take down the high points -- I'm not sure if that's a kosher idea, that'll be another question. I'm not sure what I'm using yet. To be honest, I don't much care. I tend to think bigger tile looks better and is less grout to clean. So probably something 16 inch or larger. Thanks for all the help. Feb 18, 2015 at 0:40
  • I modified the answer I gave to better reflect the question, I included some of my comments into the answer.
    – Jack
    Feb 18, 2015 at 3:47

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