Ceramic Tile Over Concrete Floor

Handyman62010

I am planning in installing a 12 x 12 ceramic tile over my concrete basement floor. This is an older house, the concrete is very smooth and appears to have been sealed years ago (dark in color, wet looking but no moisture when I did the taped plastic on floor test).

I am hesitant to use an etching acid to roughen it up unless this is the only solution. Is there any other prepping method than the acid etch to get the mortar to stick properly? Has anyone ever tried a thin coat of "drylock" wall paint on the floor? It penetrates the concrete and chemically bonds to it and has silica in it which provides a rough surface.

Any helpful advice would be appreciated.
Thanks in advance.

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Taranis

Problem with any "primer" like the one you say - it can't penetrate the concrete because the sealcoat will act as a barrier. You have to remove it, either by mechanical means or acid-etching.

Handyman62010

Can it be sanded off with a coarse abrasive or is the acid etch the only way to go? I tried sanding to see if that would work but it didn't roughen it up, It was still smooth but was lighter in color.

Question: Does the sealer I am removing penetrate or is it just on the surface?

Thanks for the reply.

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R&D Tile

Go rent a scarifier.

Handyman62010

Awesome!
Never heard of it but I will check around and see if I can find one to rent. Sounds like the solution I am looking for.
Thanks

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PrecisionFloors

You can rent one at HD for about $40 a day.

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Precision Flooring
(772) 237-9900
Tile, Hardwood, Laminate, and Resilient
Installation, Sales & Repair - "We do it right the FIRST time"

Floorwizard

you will also need an anti fracture membrane or you risk tiles and grout problems.

Red Guard is one used often around here.

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"in 20 years you will regret more what you did not do than what you did"

Handyman62010

Why would I need a floor membrane over a solid concrete floor?
I thought that was as stable as it could get...
But I am here to learn from you guys so please let me know.
Thanks again

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R&D Tile

I would go with a sheet membrane, if no cracks in the slab, not needed, but good insurance, do a search, many crack and uncoupling membranes out there, I would install Ditra or Noblecompays membranes, Flexguard is a good peel and stick one that works very well also.

BrianDL7

A company called Tavy makes a product called "Tileskin" which may work. It is a thin membrane (maybe 3 mil thick), one side is adhered to the floor obviously, and the side facing up has a rough layer similar to a rough concrete surface which mortar can adhere to easily. Honestly it would be alot cheaper to buy muriatic acid and etch your floor rather than to use a seperate substrate to cover the concrete. A product called TSP (tri-sodium phosphate) can also remove the concrete sealer, and it isn't as dangerous as using muriatic acid.

One final note - Drylok does not suggest using its product on the floor for any reason. Before you put alot of money into a home improvement job, make sure you are doing it right, so you don't cost yourself twice as much money down the road trying to fix it.

- Brian

R&D Tile

Do not use any chemical strippers on the floor, think twice about thin skin and etching the floor has nothing to do with crack isolation, anything else?

Handyman62010

Most of the floor is solid and crack free. I have one crack in an area where tile is to go. Do I use a thin membrane just over the crack area like you would tape a drywall joint or do you have to cover the whole floor with the "Thin Skin"?

I am going to rent the scarifier to prep the surface but what to do with the crack area? I hadn't thought of that as a problem.

Thanks again for all your advice!

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Floorwizard

All I know is that for better assurances that the possible movement of the concrete does not affect the tile, you need a membrane.
it's not deflection.

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"in 20 years you will regret more what you did not do than what you did"

pitterpat

Go check out the forums at www.JohnBRidge.com, post you r questions in the Tile Forum/Advice Board.

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Pat Harris
A HandyWOMAN Service, LLC
"Why call a handyman when you can call A HandyWOMAN?

PrecisionFloors

Great advice there...best tile info site on the internet by far.

__________________
Precision Flooring
(772) 237-9900
Tile, Hardwood, Laminate, and Resilient
Installation, Sales & Repair - "We do it right the FIRST time"