There is a small section of poured concrete wall in the stairwell of our basement that had vinyl tiles glued to it with tar-like black mastic in the 1960s (already tested, neither contain asbestos).

I'd like to install Dumawall PVC wall panels over it. Trying to remove the mastic is not a very enticing option. Will Liquid Nails or something similar adhere to the old mastic? Thought about priming it first with something like Zinsser Bulls Eye but fear that it won't adhere well or will chemically react with the mastic and create a gooey mess.

The Dumawall panels click together and will also be framed with an overlapping wood trim that will help hold things together but still require an adhesive.

Black Mastic on Wall

2 Answers 2


Ran a test with a sample size square of Dumawall and some Loctite Heavy Duty Power Grab adhesive that I had on hand and it seems to hold just fine. Certainly strong enough for this application.


I would use grinder with a wire knot cup. Clean strategic areas and us PL caulk to attach to the wall.

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