tiling over mastic (with asbestos) [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile


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05-17-2005, 02:09 PM
Hi folks:
I received a couple of quotes for removing linolium (with asbestos) from my kitchen floor. The flooring is agressively attached to the cement slab with mastic. Both abatement companies don't have a problem removing the the bulk of the sheeting, but they both say it's very difficult to remove the mastic from the cement.

They insist that there are some leveling compounds that can be poured over the mastic which can then be tiled.

I'm insisting the best way to tile is directly on the slab.

Can I get away with some type of levelling compound to float over the mastic once the sheeting has been removed, or should I insist on a clean cement slab?

If there are products that facilitate this, can anyone suggest quality brand names that have been sucessfully used in the past?

Many thanks

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05-17-2005, 02:44 PM
VersaBond or Flexibond is what I was told in a similar situation, but I'll let the experts chime in....

Rd Tile
05-17-2005, 07:28 PM
NO SLCs over cutback adhesive, if this is what you have, black stuff, correct?, if the floor is flat and no cracks, just use Flexbond from HD, it'll work fine, I use it all the time for this.:)

05-18-2005, 07:34 AM
Once the sheeting is removed, there is a grey mastic with some kind of felt-like residue. It is aggressively attached to the concrete. It can be forecefully shaved off with a razor scraper, but that requires a huge effort.

Will modified thinset adhere to this ok?

There are chemicals that can dissolve this residue, but my understanding is that these may often modify the surface of the concrete so that thinset will not adhere well. Is there any truth to this?


05-18-2005, 09:28 PM
honestly i was told to remove AS MUCH AS POSSIBLE of the cutback (black roofing material like adhesive that usually comes along with asbestos). i was also told that i needed to get the floor as flat as possible. in some areas it wasn't possible, but i think i managed after laying plywood over it all.
my arm (tennis elbow) and hand (tendonitis thanks to my drill) kicked in when i almost completed the job (200 sq ft).
if you go to home depot/lowes don't go buying the 14" scraper for removal of the adhesive. it doesn't have a sharp enough blade (trust me). it was good enough to almost lift each asbestos cork like tile - you have vinyl though - but it didn't help AT ALL on the adhesive. 12.5 hours later i finally finished removing it all.
unfortunately, only the 4" blade (i broke the first scraper - cutback caught in between the thing that pinches the blade tight) will be able to help scrape this sh*t up. it's gonna take some arm power babes....and buy a couple 5 packs of the replacement blades. good luck i feel for ya!

05-18-2005, 09:32 PM
oh, one more thing...
i got the impression that i needed to make the floors as flat as possible BEFORE laying the expensive thinset which supposedly sticks to cutback.
in my case, i laid plywood over it without thinset/mortar, because i needed a new layer for support.
in your case, it sounds like you want to lay tile right over it once you're done.
i am not sure if the flexbond or versibond is a self leveling compound or just a mortar. but i can tell you this; it's expensive once you get the required additives.