LVP directly over old cutback?

Discussion in 'Floor Preparation' started by indigox3, Oct 28, 2019.

  1. indigox3

    indigox3 Member


    I am a DIYer with little renovation experience. I recently purchased a 50's bungalow in Toronto, Canada.

    It had VAT in the basement. An abatement company removed the tiles, but residual cutback adhesive remains firmly bonded on the concrete slab. The cutback tested positive for asbestos.

    Can I lay floating (click) LVP directly on top of the old cutback? The slab appears mostly flat except around the drain. No efflorescence present (that I can see). Basement was waterproofed from the outside in 2014 by the previous owner.

    From what I have read on this forum, most people seem to recommend skim coating first with something like Ardex feather finish before laying down new flooring. Just wondering if this is necessary for floating LVP since it does not need to be bonded/glued to the slab?

    Thanks for any input!
  2. Daris Mulkin

    Daris Mulkin The One and Only Charter Member I Support TFP Senior Member

    The reason for skim coating is now the cutback is enscapulated and the asbestoes is covered and can't escape. Any type of abrashion can cause it to become airborne.


  3. indigox3

    indigox3 Member

    That makes sense, thanks Daris.

    Would the LVP itself prevent the cutback from being disturbed? Or it possible that the new flooring might rub against the slab a bit, causing abrasion?
  4. Chris 45

    Chris 45 Director of P.R. on some deserted island. I Support TFP

    I would think that if you paid a company to abate the asbestos that they should have abated the cutback adhesive as well. What’s the point of removing the tiles and leaving you with another asbestos problem to deal with. :hmmm:

    Anyway, I wouldn’t be so concerned with the cutback becoming airborne while it’s underneath your floating floor. I would be more concerned with it possibly still being sticky and then sticking to your floor and releasing causing noise. I’ve seen it happen before underneath wood underlayment. Or a possible reaction between the cutback and your new floor. Encapsulating is fairly easy. It’s just a couple skim coats. Cheap insurance.
  5. Mike Antonetti

    Mike Antonetti I Support TFP Senior Member

    The “reaction” would be staining the new Int’l flooring to be clear.
    • Agree Agree x 1
  6. Incognito

    Incognito No more Mr. Nice Guy! I Support TFP Senior Member

    Not only could there be problems with a noisy, crackling, sticky old adhesive but there could also be a chemical reaction from the vinyl product to the petroleum based cutback glue. CALL the tech department of your manufacturer to ensure the backing of this floorcovering is compatible with cutback glue.

    I'll bet my left testicle that they say either REMOVE the old cutback or skimcoat.

    Common sense. They have to warranty the product. They don't care about saving you a couple hundred buck in a quick skim over old glue. If you knew how quickly and efficently a professional could cover that glue I doubt you would give it a second thought.

    But it's NOT free and we cant know what your local installers might charge. It'll take HALF A DAY for a guys to scrape/sweep/vacuum/skim and then allow for the patch to dry.

    You can expect to pay for that. In some cases there might be a need for a second coat of patch to smooth and flatten out that old basement slab. It needs to be flat.
    • Like Like x 1
  7. indigox3

    indigox3 Member

    Thanks for the informative replies!

    Its funny, we had three abatement companies give us quotes, and they all said the same thing: For an extra charge, they could use Bean-e-doo to try to take off the cutback, but they couldn't guarantee it'd be completely gone, and the Bean-e-doo would leave a greasy residue. Maybe I should have gotten a few more quotes from other companies, to see if there were any other options.

    Good idea, will do. I haven't decided on a brand yet. Was thinking of Mono Serra though. It seems to go on sale regularly at the big box stores here.

    I called three flooring companies around Toronto. Over the phone, they quoted me roughly $3000-$4000 (Canadian dollars) for 2 skim coats (1000 sq ft basement). I guess that's about $2-3k USD. Does that sound like a reasonable range for the job?
    Last edited: Oct 28, 2019
  8. Incognito

    Incognito No more Mr. Nice Guy! I Support TFP Senior Member

    Seems high just to cover the old glue but it's not really outrageous if it's covering 100 percent of the floating, flattening, scraping, cleaning and preparing the substrate. Normally we'd have to put 2 coats on an older slab and then sand it down smooth when the patch is fully set. On a "floater" we'd skip the sanding and just scrape or "backtrowel" the patch to get any ridges or lumps off.
  9. Mike Antonetti

    Mike Antonetti I Support TFP Senior Member

    Too High.

    My guess is the abatement companies are ensuring the asbestos doesn’t get into air by using an encapsulating liquid. They do not care about bonding flooring, 100% Removal, which probably only way to get it airborne again is to grind it mechanically.

    I’d say there’s not much residue and the new moisture resistant Ardex Feather Finish would be the preferred product. 1$ a Ft should suffice if it’s already smooth. Unless Marks doing it, he’s worth 2$ or basically whatever he recommends.
  10. indigox3

    indigox3 Member

    • Winner Winner x 1
  11. Mike Antonetti

    Mike Antonetti I Support TFP Senior Member

    Yes, do it yourself. Start with a tiny mix then gradually mix bigger portions as you become familiar with its spreading and setting characteristics. You are Following slab so that’s your guide unless you need flattening, then that’s by straightedges.
  12. kwfloors

    kwfloors Fuzz on the brain Charter Member Senior Member

    Be sure to follow the directions on mixing exactly.
  13. indigox3

    indigox3 Member

    Thanks guys, I found a place that sells Ardex MRF for about $20/bag. Assuming one bag covers 200 sq ft at skimcoat, I should be good with 10 bags for 2 coats.

    Definitely a lot cheaper than the $3k I've been quoted...

    Are there any good instructional videos that show the proper technique?

    The only ones I've found so far are:

  14. Mike Antonetti

    Mike Antonetti I Support TFP Senior Member

    Those were horrible. Looks like they coulda cleaned the slab a bit better
  15. Mark Brown

    Mark Brown On The Surface Flooring I Support TFP

    Watching that makes me sad
  16. Incognito

    Incognito No more Mr. Nice Guy! I Support TFP Senior Member

    Those knuckleheads look REALLY sloppy Mark but that's why we want/need Ardex products. It's so good that even..........those guys and the horses they rode in on can make it work.
    • Funny Funny x 1
  17. B Akerstrom

    B Akerstrom Retired installer turned manager

    I would use a product called apac encapsule use 2 coats and its also a moisture barrier. It goes on with a paint roller goes on smooth and dries hard as a rock. No sanding or scraping or sanding necessary easy to do yourself dry in an hour.
  18. Jim McClain

    Jim McClain TFP Owner/Founder Administrator

    Got linkage?
  19. Elmer Fudd

    Elmer Fudd Administwative Asst. Charter Member I Support TFP Senior Member

    Te last i heard APAC was out of business.
    • Like Like x 1
    • Agree Agree x 1
  20. Graeme

    Graeme Pro Member

    Heads up on anyone who wants to use Bean-E-Doo. I have seen that product contaminate a slab when it was not extracted properly. The residual product destroyed 2 vinyl floors within months.
    • Agree Agree x 1

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