GBA Logo horizontal Facebook LinkedIn Email Pinterest Twitter Instagram YouTube Icon Navigation Search Icon Main Search Icon Video Play Icon Audio Play Icon Headphones Icon Plus Icon Minus Icon Check Icon Print Icon Picture icon Single Arrow Icon Double Arrow Icon Hamburger Icon TV Icon Close Icon Sorted Hamburger/Search Icon

Community and Q&A

Concrete sealer for laying tile on basement slab

Smoke Teff | Posted in General Questions on


As part of an ongoing basement renovation, I am planning to lay tile on the concrete slab. I’ve read that it’s wise to use a concrete sealer between the slab and morter for moisture-proofing purposes–I’ve also read that this sealer should be flexible/elastomeric in order to help prevent cracks in the tile.

I sealed the walls in black liquid rubber foundation sealant and have a few gallons leftover. Would this work? One source said rubber was ideal, but another said a sodium silicate or lithium silicate based sealer was ideal. 

Any opinions/advice?

GBA Prime

Join the leading community of building science experts

Become a GBA Prime member and get instant access to the latest developments in green building, research, and reports from the field.


  1. Expert Member
  2. Smoke Teff | | #2

    Hi Malcolm,

    I assume that link means you're endorsing that product as one that would work in this situation. I can't tell, however, if you're suggesting that the product I mention is inappropriate or wouldn't work for some reason.

    That product can be found here:

    1. Expert Member
      Malcolm Taylor | | #4

      Yes. Redgard is made for exactly what you are doing, and has a great track record. Keith has given you good advice about what you are suggesting as an alternative.

  3. Keith Gustafson | | #3

    I think the problem with your idea is that it is not intended to lay tile on, or be indoors.

    There could be bonding issues.

    Or not

Log in or create an account to post an answer.


Recent Questions and Replies

  • |
  • |
  • |
  • |