JohnfrWhipple
BATHROOM DESIGN & BUILD
You need not be in this business for long time before the pickle of having to work over a painted concrete surface comes up. Front deck. Back patio. Basement mudroom or ground floor laundry room you need to figure out this step before going to far along.
I do not know of any product designed to work above or onto of a painted surface (concrete). That said I have tried a few approaches over the years.
On my old front deck (12 years ago) had flaking painted concrete slab. Nasty. Paint flakes all the time getting tracked in.
I rented a pressure washer and hit the front porch hard. Then I used my wire cup wheel and grinded the surface.
Then more water.
But - the surface was still littered with paint and I said **** it and went right over top with my tile prep. This was the firs time I used Grani-Rapid from Mapei to set Ditra. It worked really well. The Ditra sat down nice. The slate tile went it. I grouted with Ultra Colour Plus and for over nine years this black slate tile on my North exposure served me and my family well. Since then we have removed this front deck and added a floor to my home.
My new back deck is tiled and this time I worked over new construction. The slate tiles installed over NobleDeck, over cement board, over double ply, over double 2"x10"s on 12" centres. A TANK.
I have tried basic thin-set - unmodified and it sticks so poorly to a painted surface you might choose to instead burn your money versus spending hundreds of dollars and have tiles popping up.
You need a bond. And the weakest point is the paint. If the thin-set reacts with the paint and weakens the paint you are screwed. So - how do you check?
Do a test. Set a little tile over the painted concrete after you make every measure to rough up the surface and remove and loose bits. Leave it for a couple days. Then bash it off with a hammer.
What happens?
Did it come off to easy.
Did it shatter and stay stuck to the floor.
Did the paint peel away and the thin-set is still stuck to that.
This should give you a basic idea of how things are working.
Now if you can not get a chemical bond then you will need to switch to a mechanical bond. Visions of 1/4" wonder board and expanded diamond lath come to mind.
I do not know of any product designed to work above or onto of a painted surface (concrete). That said I have tried a few approaches over the years.
On my old front deck (12 years ago) had flaking painted concrete slab. Nasty. Paint flakes all the time getting tracked in.
I rented a pressure washer and hit the front porch hard. Then I used my wire cup wheel and grinded the surface.
Then more water.
But - the surface was still littered with paint and I said **** it and went right over top with my tile prep. This was the firs time I used Grani-Rapid from Mapei to set Ditra. It worked really well. The Ditra sat down nice. The slate tile went it. I grouted with Ultra Colour Plus and for over nine years this black slate tile on my North exposure served me and my family well. Since then we have removed this front deck and added a floor to my home.
My new back deck is tiled and this time I worked over new construction. The slate tiles installed over NobleDeck, over cement board, over double ply, over double 2"x10"s on 12" centres. A TANK.
I have tried basic thin-set - unmodified and it sticks so poorly to a painted surface you might choose to instead burn your money versus spending hundreds of dollars and have tiles popping up.
You need a bond. And the weakest point is the paint. If the thin-set reacts with the paint and weakens the paint you are screwed. So - how do you check?
Do a test. Set a little tile over the painted concrete after you make every measure to rough up the surface and remove and loose bits. Leave it for a couple days. Then bash it off with a hammer.
What happens?
Did it come off to easy.
Did it shatter and stay stuck to the floor.
Did the paint peel away and the thin-set is still stuck to that.
This should give you a basic idea of how things are working.
Now if you can not get a chemical bond then you will need to switch to a mechanical bond. Visions of 1/4" wonder board and expanded diamond lath come to mind.
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