VCT Adhesive Failure

dmranney

About 18 months ago I installed some VCT over a bare concrete basement slab. After a few months, sticky, runny liquid oozed out between tiles when walked on. Not everywhere, but scattered locations. The problem got better or worse over time, but never went away. Last week I pulled up a few tiles and found puddles of thin, watery adhesive here and there.

Here's the exact install procedure:
Old VCT tiles removed. Black asphaltic mastic removed with Bean-e-doo stripper. Floor rinsed thoroughly and left to dry for two days. Mannington V-11 latex adhesive applied with notched trowel. Adhesive took 4-5 hours to skin over, translucent and dry but sticky to the touch. New 12" VCT applied.

Homeowner believes there is a sub-slab vapor drive problem, as it's a walk-out basement and the problem is only in the deepest buried area of the basement. He had a perimeter drain and sump installed last month.

The adhesive was definitely all skinned over when installed, so it appears that it must have actually re-dissolved in order to create these puddles. Is that possible? Would vapor drive be able to do this, or was the slab not allowed to dry well enough after washing?

Any suggestions to prevent a reoccurrence when replacing the bad tiles? Like seal the slab first or use a solvent-based adhesive? I've never seen this before so any insights are welcome.

rusty baker

4-5 hours for the adhesive to skin over is too long. Must have been moisture present or the floor was too cold. High humidity?

mdshunk

Funny you mention this, because this is pretty timely. Just happened to me in a rental unit. The flooring installers ended up doing an alkaline test on the concrete (with the adhesive rep in tow). They determined that there were high alkaline levels present that dissolved the adhesive. They pulled up all the tile, stripped the glue, sealed the concrete with some clear crap they put on with a paint roller, and reinstalled the tile. The rep had heard of the problem before, had a white paper that warned of high concrete alkalinity, but it was a new one on the installing contractor. The end result is now fine.