Engineered Wood Floated Over Black Mastic?
We recently had minor flooding at our house, which affected an area where I had previously installed engineered wood flooring (floated, with foam underlayment) over old but intact linoleum tiles. The insurance demolition people took out the engineered wood, the underlayment, and the linoleum tiles, but left the black mastic that was underneath (on concrete). I want to reinstall the engineered wood flooring with new underlayment. Do any of you see any problems with leaving the black mastic in place and just installing the flooring right over that? Or is there a good reason why I would have to remove the mastic?
By the way, the demo people had the linoleum and mastic tested and it does not contain asbestos.
Thanks in advance for your recommendations. Mark
Replies
Be aware that the black mastic is apt to contain asbestos fibers. For this reason it may be best to NOT try to remove it.
Asbestos?
The demo people had the tiles tested and they showed no asbestos. I would imagine that that would include a test of any mastic residue on the tile, too?
I have no idea whether they would have tested the mastic or not. I just know that there are cases where the tiles are fine but the mastic contains asbestos.
Best I call them in the am. Thanks.
mastic vapor barrier
The mastic acts as a vapor/moisture barrier. Leave it. Make sure your concrete floor meets the requirements set forth by the manufacturer (moisture etc). Your primary concern is to not trap moisture between the concrete and the e-floor. Be sure to lay a new blanket of foam padding (which acts as a second moisture barrier) before installing new e-flooring. That said, I am not a fan of floating floors, but given that concrete can crack over time, this may be the best way to go. You can call the e-floor manufacturer and ask for advice. Be aware that the manufacturer has to protect against future claims, so the advice given will be on the super-cautious side.
Vapor Barrier
I was thinking mostly of the "interaction" between the foam underlayment and the mastic, but it sounds like the vapor barrier is a great benefit of leaving the mastic as is. But I'll contact the underlayment manfacturer to see if they've got any reservations about just laying their product right over the mastic. Thanks much!
HINT: Primer and Rosin paper
HINT: If there is any lingering concern, lay rosin paper over the mastic and lay the foam pad on top of the paper. As I pointed out earlier, the manufacture of the pad and/or the flooring product is primarily concerned with warranty issues. The pad manufacturer, for instance, does not want to assume the burden, real or imagined, of pad adhering to residual material. Manufacturers usually insist you follow installation guidelines. It is for YOU to determine if the perceived risk is worth taking. For added peace of mind you might want to explore how to lock/seal old flooring residue with a primer coat. Then rosin paper and pad.