We had a basement flood, and consequently had to rip out the vinyl floor tiles in our basement. The tiles were not asbestos (we had them tested).
But after the tiles came up we discovered that they had been secured with black mastic. The adhesive did test positive for asbestos, 4-5%. So now we need to figure out the safest way to proceed with getting new tiles in, in light of that potentially dangerous material.
Contractors we have spoken to think the best approach is to put down new ceramic or porcelain tiles right over the existing adhesive. They said "capping" the mastic in a seal coat or thin layer of concrete wouldn't be a good idea- they'd need to pour rather a lot of concrete for that.
Originally the contractor wanted to grind the floor (which I've read is exactly the wrong thing to do if mastic has asbestos!) When I balked at the grinding, he said he'd instead use a "fortified mortar" to lay the new tile down. I believe he also referred to this as "high polymer" mortar.
My question: can you lay down ceramic/porcelain tile over existing mastic without grinding the floor? Will it adhere suffiiently? Is there a better/safer approach?