Engineered Hardwood Floor Installation?

[Steve]

I'm considering installing engineered hardwood flooring in my house. The house is built on a concrete slab, so traditional tongue & groove flooring nailed to the subfloor is not an option. So gluing an engineered product with a finished hardwood top layer is the material of choice. But I'm getting conflicting information on what is needed in the way of surface preparation. Two questions:

1) Does the surface of the concrete need to be leveled as you would do for ceramic tile, or does the adhesive used for wood flooring perform that function as well?

2) Do I need to seal the cracks in the slab before I put down the flooring? The house is 9-1/2 years old, and settling cracks have developed in the concrete in just about every room - none over 1/16" wide, but I'm thinking these cracks could be a path for ground dampness (and maybe termites?) to get at the flooring.

Thanks!

--Steve

[AZ Nomad]

It depends on the flooring. RTFM.

I recently installed 'fake' wood flooring which locked together but floated on the floor. I would assume that you need to level the floor or the flooring is going to creak.

[Edwin Pawlowski]

It does not have to be as perfect as tile. Check to see if gluing is acceptable for you flooring. Most on or below grade should be install with a poly barrier and floating.

They don't have to be sealed, but there usually is a barrier.

[Steve]

Steve wrote on 04 Mar 2008 in group alt.home.repair:

You've gotta do what the instructions tell you to do. The product literature will tell you how much variation is allowed in the floor, what kind of preparation, and what kind of adhesive to use. This will give you the best result, based on the manufacturer's research, and it will protect your warranty.

Most likely, the adhesive will seal small cracks and fill shallow low spots. You can *probably* use a product like RedGard to seal bigger cracks. You'll have to use a cement-based product to seal large cracks.

By the way, you *can* put solid hardwood flooring down. You just have to put down 3/4" plywood first. This leads to all sorts of level and transition issues, but they can be addressed.

[Malcolm Hoar]

Yes, I'd be amazed if the manufacturer doesn't require a vapor barrier when installing over slab as a condition of the warranty.

Hey, it's cheap and easy -- there's no reason to skip on the barrier.