TILE OVER CONCRETE CRACKS

[Tim Conde]

I am doing the floor tile in a house that is around 50 years old. The house was built by "kids" back in the 60's and they made a lot of errors. Examples: the aggregate used in the concrete was smooth river rock. No wall insulation was required so none was done. Several drain pipes under slab were barely sloped and on and on.

Now, the homeowner wants to put in floor tile throughout the house. There is no carpet in the house, only 50 year old lino tiles. We knocked a few loose to see what was going on under and everywhere we looked we found spider cracks. Lots of them. The cracks start in stress points of the pour and meander through the slab all over the place. There is not a lot of displacement (1/16" max), but water is leaching up through the cracks in several places.

Without tearing the whole slab out and repouring it, does anyone know of anything I can do to the slab to put new tile down and have it last? People have suggested anti-crack sheet membranes, roll-on membrane solutions, patching the cracks somehow, etc. I am trying to get the slab leveled out, and put 18x18 floor tile down that will last.

Anyone have any ideas for this?

[benick]

Yea , RUN not walk away from that job...I see nothing but problems in your future and if the home owner doesn't like it he will be on here whining about how he was taken for a ride by an evil contractor..LOL...All kidding aside , I won't do shit jobs....Bad for the reputation and rarely is the owner happy and you could be going back forever trying to fix it...I see NOTHING good coming out of it...JMHO.....

[jloomis]

That is a tough one. I had to put a special layer of 1 1/2" concrete over a floor similiar to your floor for tile and or........whatever.....with no promises. The owner liked it, and ended up staining the "new concrete" and voila. The moisture coming up is bad news though for you. That will not stop. I had to put a good sealer on the existing concrete to minimize moisture although the slabe did not have that problem. What about a waterproof membrane, sleepers, and wood floor? I did this in a garage floor situation.....turned family room. It came out very nice, althought I had room for material heights and ventilation. They do make concrete overlay also for floors. See the "Concrete Colorist" for ideas........ Your moisture problem is limiting my ideas....... john

[Mike]

You may want to look into Schluter Ditra if you are using a stone or ceramic tile. Not cheap though. Mike

[reqluq]

Why don't you find where the water is coming from first and see if that can be solved..How big are the *spider cracks*? if smaller than the side of a credit card it should not be an issue req