[jfloor]

Hi there,
We are planning on applying/installing porcelain or ceremic tiles on a cement base. The area is located next to out garage and its nearly (12ftx8ft) in area. The area use to have a green outdoor carpet glued to the floor. Here are my questions:
a) We have taken out the glued carpet and the foam/rubbery material under it but we are not sure if we need to clean the surface more or its good to go for installing tiles. Please find the image 1 attached for your reference.

b) There is a crack in the cement that goes all the way across the area and through the garage. I am a little bit concerned about this being a structure problem or its a normal wear and tear for an old house. Please find image 2 attached for your reference

c) There is a 1/2inch gap between floor and the wall. I am planning on putting expanding foam and caulking but I am not sure if this is correct way to fill the gap. Many articles on internet suggests not to block it/cover it because it was left there for cement to expand.

d) We are planning on putting a waterproof membrane on the cement floor like this one (Waterproof-Floor-Uncoupling-Mat-Underlayment-CI-5m-B/304276429) and then just laid out the tiles on it, is it good enough or we have to do use some other materials in between to keep the flooring safe from moisture.


Any advise is highly appreciated. Thank you

 

[chandler48]

Where are you located? Filling out your profile will help us know how to address things. Mainly, if you are in Colorado, that floor will heave with the seasons, and should be left alone. We'll see once you post location.

Using Ditra or similar isolation mat embedded in thinset over your concrete to isolate the crack and keep your tiles from potentially cracking.

 

[jfloor]

@chandler48: We live in southern California. Thank you for your suggestion

 

[carpdad]

https://www.tcnatile.com/faqs/28-carpet-glue-residue.html


I have tiled over such floors. Long time ago and less careful. Above article does not definitively say one way or another but very good recommendations, esp that carpet glue could have been water soluble. Once cured, it may not feel like it. See if wet rag with alcohol brings up residues. I say alcohol because it will dissolve water based paint. It shouldn't do much if the glue was oil solvent based. If it does, I would remove the glue or look for primers. Check mapei website (not endorsing the brand although it seems to be most used) for primers and further info about carpet glue. As in the article, carpet/vinyl tile glue was also called cutback glue. Demolition impact hammer/drill with a scraping blade can remove the glue quickly. Ok if the concrete floor gets somewhat scratched or gouged.


Using a decoupler is a must, I think, since there is a crack already. The membrane adheres with thinset so the glue question is important.

 

[rusty baker]

https://www.tcnatile.com/faqs/28-carpet-glue-residue.html


I have tiled over such floors. Long time ago and less careful. Above article does not definitively say one way or another but very good recommendations, esp that carpet glue could have been water soluble. Once cured, it may not feel like it. See if wet rag with alcohol brings up residues. I say alcohol because it will dissolve water based paint. It shouldn't do much if the glue was oil solvent based. If it does, I would remove the glue or look for primers. Check mapei website (not endorsing the brand although it seems to be most used) for primers and further info about carpet glue. As in the article, carpet/vinyl tile glue was also called cutback glue. Demolition impact hammer/drill with a scraping blade can remove the glue quickly. Ok if the concrete floor gets somewhat scratched or gouged.


Using a decoupler is a must, I think, since there is a crack already. The membrane adheres with thinset so the glue question is important.

I would not scrape up cutback unless you keep it wet. It normally contains asbestos.

 

[firehawkmph]

I would not scrape up cutback unless you keep it wet. It normally contains asbestos.

There's a couple of soy based cutback removers on the market that work very well for disolving the old adhesive and wiping it up. I've used the one called Bean-E-Doo with very good results.
Mike Hawkins