I have enjoyed reading the great advice on this forum for hardwood installations. My husband and I are planning our first install, most likely of engineered wood, and are trying to decide what to do to prepare our subfloor, which is a broom finished concrete slab.

Because approximately 1 gallon of peanut oil was spilled on the slab , we are not sure how clean we can get it for an application of an Ardex product to even out some small dips, or for a vapor barrier such as Bostick's MVP.

We are considering:

1) Floating subfloor of 1/2" plywood screwed and glued to 1/2" plywood as mentioned in other posts, with 6-mil poly underneath and asphalt felt on top. The only height concern we have is with the exterior door (which has not been installed yet)....the step "up" might be a little high.

2) Application of Bostick's MVP, then nailing 1/2" plywood to the concrete with a nail gun.

3) Cleaning the slab as best as we can, then gluing vinyl down, then gluing to the vinyl.

The Ardex rep we spoke to said that to use their product, we would have to clean the oil up "as deep as it penetrated into the slab," and we aren't sure how to do that, or if it is possible. We appreciate any recommendations.

Any suggestions?

Sorry Grace,

I read your post but do not have a suggestion. I do know that oil will interfere with an adhesives ability to bond, either with wood or concrete. Seen that first hand. But how to get it out I have no idea. Wish I could be more help.

Thanks for your reply, Gary.

1) Since we might not be able to use a cementious overlay in some spots for getting the slab flat, should we use felt paper as Kahrs recommends?

2) We like the Kahrs Woodloc products. In our case, should we use a poly vapor barrier, then the Kahrs underlay, then the Kahrs Woodloc flooring?

3) We like the look of the two-strip Kahrs more than the three-strip. Does the builder grade look more like the three-strip?

Thanks!

Yes, I believe the builder's grade is a 3 strip longstrip floor. I think a floating floor may be your safest bet and Kahrs is a great choice. If floating a Kahrs floor, they have instructions online. I believe using felt is an acceptable way of furring up low spots. However, on concrete, it is more difficult to keep it in place and Karhrs recommends a cementious patching compound.

http://www.kahrs.se/templates/KahrsExtr ... ntid=13730