My basement is prone to getting water in it after big rains. I know that we definitely have a leak in the wall on one side of the basement so we're having a contractor come in and demo the whole basement and excavating the exterior in hopes of finding said leak. They are pretty confident they can find it easily and patch it up. Then I think we'll DRYLOK the whole thing as an added safety measure.

The other day when I was down there, I noticed several small piles of white dust scattered throughout the basement floor. I've researched this and I think what I've found are calcium deposits which I understand appear as water and moisture come through the concrete. (Am I right so far?)

I'd like to ultimately porcelain tile the basement floor (right now it has linoleum tiles) but I'd like to seal the floor somehow first. I read that DRYLOKing it will cause the thinset to not bond properly when laying the tiles. Are there other options out there?

  • You cannot tile a basement floor like that. Well you can put you will almost instantly have issues and not one will spend countless hours installing but also countless hours ripping it up. They make very good "rubber" plank click lock flooring that looks like tile. In your basement I would go with this.
    – DMoore
    Aug 20, 2013 at 17:34

1 Answer 1


Unless you truly fix the water intrusion, sealing the floor will not work. I would do a moisture transmission test in your 'wet season', after the repairs are done: secure a foot square of plastic to the floor in several locations. You should review the information here: Basement floor with lots of moisture.

A moisture meter (this one has a masonry setting) for before, during and after readings, will give you a lot of information.

Porcelain tile will, in effect, seal the floor, since porcelain tile is impervious to water (<= 0.5% water absorption). Be sure to use portland cement based thinset (the dry kind, NOT a premixed mastic "thinset").

  • Thanks HerrBag. Your suggestions are all part of my plan. I understand that the tile is impervious to water but the grout will not be, so I want to do my best to prevent water from coming up from the floor. I just don't know if the thinset (yes real, powered thinset) will bond properly to a sealed floor. Aug 20, 2013 at 17:21
  • You COULD use an epoxy grout, but my point is not to try to seal a floor, water will win. You would be better off letting a bit of vapor go through the grout, than to have the slab crack. If you do decide to seal, go a year before covering over the sealed floor.
    – HerrBag
    Aug 20, 2013 at 18:43
  • I might be over thinking it a bit.. 99% of the water that is in the basement comes from the same wall every time. I'm sure fixing that will fix most of the problem. There will still be a couple of spots that I've seen with calcium deposits, but that might be residual from the impact from hurricane Sandy. The other thing that was suggested to me was to use DITRA underlayment to provide some waterproofing to the tiled floor, instead of sealing the floor. Aug 21, 2013 at 1:10
  • I'm a big fan of Ditra. I'm just leery of asking a membrane to stop water flow from the INSIDE. Sounds like you will stop the intrusion. I REALLY don't like vapor barriers on basement walls unless there is closed cell foam to prevent condensation.
    – HerrBag
    Aug 21, 2013 at 12:47
  • Thanks for all your help @HerrBag. I'm still 4-6 months away from starting this work so I've got plenty more time to come up with a plan but this has been great info. Much appreciated. Aug 21, 2013 at 16:56

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