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sgjordan 04-28-2013 07:44 PM

Tiling on top of adhesive
Ok, I know that you aren't supposed to tile over carpet adhesive, but I wanna. I pulled up the carpet 6 months ago and the glue (what's left) is not tacky. There isn't much left as I've spent hours scraping it. Below the carpet adhesive is black cutback with possible asbestos. I put a metal wire attachment on my angle grinder, and it would take off some carpet adhesive and smooth the black beneath. Possibly mixing them. I also have some old paint on the concrete floor on the other side. This is a nightmare. Can I just tile over it after I get anything that is remotely loose off?

oh'mike 04-28-2013 08:02 PM

Yes, you can tile over it---but you need the best thinset to do that---

Jaz might be able to offer a suggestion for a modified that will work---I use Kerabond (unmodified) mixed with Keralastic---(liquid latex?) --key it in first (flat side of the trowel) then add more and comb out your thinset---

In some situations, I will bury (encapsulate) the adhesive under a layer or self leveling compound--
For this, I use Jifset mixed with Linewebers liquid latex---That is an approved method and has always worked for me----

JazMan 04-28-2013 08:56 PM


I think Mike's suggestion of using a self leveling compound is the safest. Be sure the SLC you choose says it's ok for the conditions.

It's also likely that it may work using a high end thinset like Kerabond with Kerlastic. You can't get much better. However they all tell us to remove the old adhesive until there is only a film left. By that they mean you will see concrete through the film.

BTW, please do not dry-grind the floor if you suspect asbestos. Best way is to use a razor scraper but keep the floor wet as you scrape. It's no fun, but doable. The paint should be removed too.

Tell us more about this room. Big, small? I assumed it's concrete, yes?


cleveman 04-28-2013 10:31 PM

I have suggested this before. Just mix up a pound of thinset and set a few scrap tiles in the worst areas and see how it works out.

sgjordan 04-29-2013 07:16 AM

Just under 200 sq ft. Concrete floor. House was built in the 50s and this mudroom was an addition built a while ago, but I don't know when.

sgjordan 04-29-2013 07:26 AM

Why is it that a Slc can adhere to the floor but a thinset cannot? I'm no tile pro, I'm a just a glass guy that has had success with a wide range of other projects, so please excuse my ignorance. But the products seem similar.

sgjordan 04-29-2013 07:46 AM

While I'm posting multiple postings, I'll add that the floor is not level. Not even close, it's about 1 1/2" out over 18' (length of room). Also, this has nothing to do with flooring, it is outta square by 2" over 11' (width of room). I think that this was originally a driveway that went between the house and garage. I've done so much to this room already, this is truly turning chicken $hit to chicken soup. Thanks for all your help.

oh'mike 04-29-2013 06:48 PM


Originally Posted by sgjordan (Post 1169262)
Why is it that a Slc can adhere to the floor but a thinset cannot? I'm no tile pro, I'm a just a glass guy that has had success with a wide range of other projects, so please excuse my ignorance. But the products seem similar.

You are correct---some thinsets are fine to use over bad surfaces---

The self leveling compound, done correctly, will not only bond to the lousy concrete--but bury the loose bits of carpet adhesive that might come loose as you are troweling down the thinset---

There is little worse that finding bits of crud in the thinset---

JazMan 04-29-2013 09:24 PM


I doubt that floor was once a driveway. Driveways do not have footings, was probably what's known as a breezeway here in MI.

The floor does not have to be level, but it must be flat. Homes built in the '50's didn't get tiled, and few are flat enough. You need to get a long straight edge and determine what it needs to get it flat. The floor needs to be; within 1/4" in 10 ft. and 1/16" in 12", of the desired plane.


sgjordan 05-02-2013 09:02 PM

Thanks Jazman. I have the self leveling concrete down, and I'm ready to tile. I'm using the wood look-a-like tiles. They are 6x24. What size trowel should I used for this size tile. Thanks.

JazMan 05-02-2013 09:50 PM

Make sure the SLC came out flat before you continue. Get a long straight edge and check in every possible direction.

Use a 1/4x3/8x1/4 trowel. What thin set will you be using?


sgjordan 05-02-2013 10:48 PM

I was going to use custom blend from Home Depot with the ad-mix concentrate.

sgjordan 05-03-2013 07:55 AM

Or should I use versa bond?

sgjordan 05-03-2013 08:13 AM

Porcelain tile...

sgjordan 05-03-2013 09:14 AM

Ok, just left the Home Depot. I am in possession of
Custom blend ( without additive ) and versa bond. My guess is that versa bond is the better option.

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