I am tring to find a way to put tile over painted concrete. the paint is lead based so I cannot removed it. It was exterior steps but have closed it inside now. now they want to tile it. No problem on the stability, the tile will be fine. Was wondering if your could thinset Durrok and use tapcon screws to hold it encasing all the stairs as well. Will this work or anybody have any ideas.

Hi Trigger ..... you're thinking in the right direction but it won't work. Nice if it did though.
I used a mortar bed over a slurry for this job. I was required to raise the height of the top 2 steps in relation to the increased height of the deck.
In your case you would also want to mud the face of the risers. Fat mud (mortar-mix) mixed with latex would work fine for the job and would be MUCH easier to use than the deck mud (sand-mix) that I used here.
Your bed would only need to be around 1/2" thick.

thanks harry. I thought of that but will the mortar bed stick too the paint and should I be adding ditra on top. These people are tiling it no matter what. I would like to guarantee it but not sure with the paint. thoughts on this. by the way why would the durrock not work. out of curosity. Is it the moisture from under neath and the sweating of the concrete. Thanks

Durock must be set into a bed of thinset mortar and screwed, and if the paint (as you correctly pointed out)loses it's bond ... the screws regardless how they are set will not hold the cement board into place. Cement board isn't contructed in a way to be able to depend on just a mechanical fastener or just a bond coat. It must be both when over plywood only ... over concrete (vertical or horizontal)is a no-no.

Wedi board may be used over concrete .... but then again you have to concern yourself with the bond between paint and concrete.

If you don't want to remove the paint, a mortar bed over an anchored layer of lath would be ideal .... but a lot of work and certainly not cheap in regard to labor.
Bottom line ... if the bond of the paint to the concrete is going to dictate the type of installation you proceed with, then this is the only thing I can think of which would be up to proper standard.

Someone else might have an idea more up your alley.

Even if it is paint with lead in it,I'd remove it with a scarifier or concrete surface grinder.I have a Bosch surface grinder with a vacuum port on it ...and with a good vacuum there is no dust present when grinding.

Boy, I will tell you, this has gotten to be a headache, guess it comes with the job. I thought about grinding too but under comp laws and enviremental laws I am not suppose to touch it. All is great if nothing happens or nobody hears about it, but my luck that will not happen. Also owner does not want me to scr it up either. I like Harry's idea of mortar bed. that was my first thought about how to go about it, but give up on the idea when I did not think the screed would stick to the concrete. Harry you said to anchor the mesh to the concrete, how would I go about that. I usually put an acrylic additive in my screeds would I increase the concentration in this one or leave the same. Also do you guys think I would use some sort of bonding agent on the concrete. Last but not least do you think ditra is nessesary Thanks guys

I know this thread is "for all the experts"...but I'm going to chime in here anyway.

Get one of your men to remove the paint trigger. Just say you've got an estimate to do or something.

If your customer is willing to forget any warranty on those steps, then Keralastic would bond pretty well to the paint. All you would have to do is hope the paint stays on the step.

And yeah, if your going to do a mud bed, then tapcon down some wire mesh to the steps. Even if it doesn't stick to the paint, it will still be sturdy enough to support the tile.

hey bri hoe are ya?
thought about keralastic too but the steps are so far out of wack need to level up some how. gotta go for a walk with the boy be back in a bit to discuss farther see ya

Rusty

Well then, I think a combination will work. Tapcon on some wire lath, then use Keralastic slurry over the wire, and then the mud. IF it comes loose from the paint, it will still be held in place by the wire. Plus, you get to make the step to fit the tile...which always comes out looking really sharp.

Unless Harry or Ron thinks it's best not to use the bond coat with the wire? It has always worked for me...so far. :rolleyes: