A good polymer modified thinset will stick just fine. If you are really
concerned, paint on a layer of concrete bonding compound or use latex admix
in the thinset (see bag instructions, more expensive thinset already has it
inside). BigBox has about 5 or 6 kinds in the store, you want the third
down from the most expensive (unless you want white)

I used this method on painted concrete with no problems yet.

If the sealer is more like a thick coat of polyurethane which can peel up on
its own, you will want to strip it or score it to expose much of the
underlying concrete. Sanding with a concrete brick works well in this
situation.

wrote in message
ups.com...
I'm working on tiling my house and have just got to the kitchen.
(approximately 95 sq/ft)

After pulling up the linoleum, I find that the concrete has been
treated with some kind of sealer, so that it repels water.

Hopefully you experts here will be able to give me a word of advice as
to what to do next?

Can I lay my thinset right on top of this sealed surface, or do I have
to treat it in some way?

Your help will be appreciated.

Lewis.

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