In my new store i am ripping out a section of carpet and laying down vinyl tile for the produce area.
The carpet was glued down, and has obvious glue residue left over.
Neither my father or I are tile experts and just trying to learn as we go from Youtube videos and DIY information, however it always seems the tile they lay is on a clean (new construction) surface.
My father is adamant we rent a large sander and sand the glue residue down to bare concrete.
My thought is, as long as the new glue covers all of the old and is evened out, it should work out fine.
Help us out SDMB!
Something I didn’t think of when I did a similar project: the glue residue could contain asbestos (depending on age etc.). Grinding the floor creates a fine dust that penetrates everything, including dust masks. On the other hand, 2 different liquid adhesive removers didn’t work sufficiently well for me.
I’d send some of the adhesive off to test for asbestos. If it doesn’t contain any, grind away. (Rent concrete grinder, or, more laboriously, get an attachment for an angle grinder).
You don’t want to try to put vinyl tile down on a surface that is even slightly uneven. The unevenness will translate through the tile and possibly cause some corners or edges to pop loose over time.
I googled “asbestos in carpet glue” and apparently that is a thing. If you send a sample for testing and they find asbestos, you will be required to use a licensed contractor to remove it (and some damage may already have been done by removing the carpet).
But having said that, remove the carpet glue no matter what it takes. Shortcuts never pay.
Possible alternative that could possibly work: install subflooring over the glue, and then tile that. You would have to attach the subflooring to the concrete, which I’ve never tried, but I think it can be done with a special nail gun. This would raise the floor by 5/8" or so but it might be easier than grinding.
The carpet was put down in 2006, possible asbestos glue was use this late?
Get a floor scraper, a pack of blades, a mop and a bucket. Wet the floor, scrape, mop up, and repeat. Keeping it wet will greatly reduce harmful dust getting into the air.
We are very careful at work about disturbing vinyl tile and have staff with asbestos tickets to deal with it when we do. Carpet glue just gets scraped. I’ve never heard of the guys worrying about it. Mind you, I’m the guy that rebuilds stuff, not the guy that demos it so I do not have asbestos training.