I had a leak/flood recently, had to get rid of old linoleum and carpet. Now the concrete floor is exposed. Fans dried out the place for 4-6 days. I want to put engineered wood flooring on top of the concrete slab. Due to the moisture from flood, do you recommend just a moisture barrier sealer, or sheetings before putting on the flooring? How about plywood first? The place was soaked overnight. Moisture crept up walls 8 inches. I heard it's good to put plywood planks first, or a vapour barrier to seal concrete first. For the sealer, the flooring guy wants $1000, isn't that excessive?
Andrew K. ~ Irvine, California
Hi Andrew. It depends on what type of engineered flooring you plan to install. If you are installing a glue down flooring over your concrete slab, then I would recommend a sealer be installed on the concrete prior to the floor being installed. If you are installing the type of engineered flooring that is just laid in place and the trim secures it, then I would lay a moisture-barrier sheeting down first.
I have installed sheets of plywood over a concrete slab prior to installing wood flooring, but I don't put it directly on the concrete. I install framing strips, or "sleepers" as they are sometimes called, to the concrete and then nail the plywood in place. The hardwood is then glued or nailed to the plywood. This method provides a little extra cushion to the hardwood but can create problems due to the height difference where it meets adjacent flooring. When I use this method, I install a moisture-barrier sheeting prior to installing the sleepers.
I'm not sure how large the room is so it's difficult for me to judge on whether $1,000 is a fair price. I do know that high quality concrete sealer can be expensive to purchase. You may want to have a few additional flooring contractors from around Irvine come out and give you an estimate for the work--that should give you a pretty good idea of whether the costs are reasonable.
It sounds like you had quite a bit of water in the room during the mishap. Most residential concrete is not sealed prior to flooring being installed, and without sealer concrete can be absorbent. It may be worth your while to place a dehumidifier in the room for about a week prior to installing your flooring. The fans may have dried out the surface of the concrete, but it could still be fairly wet where it's not visible. You might want to take advantage of the extra time to examine the water damage to the walls of the room as well. Eight inches up the walls is fairly high, and the sheetrock and any insulation behind it could be damaged and susceptible to mildew or mold.
If any additional repair work needs to be done, doing it before the new floor is installed might prevent it from being damaged. It may be worth your while to have your walls inspected for mold and mildew if you haven't already done so. It doesn't cost very much and I would think there would be some very good companies that specialize in these inspections scattered around California.