||11-26-2007 11:09 PM
Prepping concrete subfloor for laminate
I plan on installing about 1000 square feet of laminate over the majority of my first floor, which is concrete slab. The majority of the floor was previously covered in ceramic tile. I have most of that up now (talk about work). Some of the floor was also previously carpeted.
While taking up the tile and thinset (BTW I used a demo hammer and 6" floor blade), the concrete slab got some small chips in it, it looks kind of like pock marks. Most of them are about 1/4" wide and 1/16" deep. Also, when I took up the tack strips in the carpeted areas, I got what I would describe as "divets" of concrete that came up with the strips.
I keep reading that the subfloor needs to be "flat, level, and clean" before installing the laminate. Does it have to be smooth as glass? I'm hoping that the right thing would be to use some sort of patching compound for the larger "divets" and hopefully not have to do anything to the "pockmarks". There are also some small ridges where the thinset didn't scrape clean off the slab. These ridges are 1/32" to 1/16" high. Again, how smooth does it have to be?
Also, I have a long crack across the slab. It varies in width between hairline and 1/16" and has no difference in height. The underlayment I'm using has a vapor barrier, so do I need to caulk this crack?
BTW, the laminate is a Mohawk 9.5MM and I'm using the Floor Muffler underlayment.
Thanks in advance for everyone's help, and if I have this many questions in the "prep" phase, imagine how many I'll have when I get started :huh: