Solid Hardwood, Engineered and Laminate Flooring - need advice on parquet over concrete fix

I've got oak parquet that was cemented (black adhesive) directly over concrete, and over the years, it has developed hollows under the planks. This results in annoying noises when you walk on it, and I'm trying to figure out the best way to silence them. I'm considering drilling into the slabs and injecting expanding foam or something. Are there any better methods for this sort of repair? Thanks for any help.

Bostiks has a fix it kit, so does Pro-Jection, and Dri-Tac.

Drill a small 1/16" hole in the dark grain above the hollow spot and inject glue or better yet, epoxy, or black mastic.

Thanks very much for the advice! I'm wondering what would be the best filler to use, as in some cases, there's a large hollow area that needs to be filled. Also, I have to consider what I can fit through a 1/16" hole - I may have to drill a larger one. That should be okay, as I'll probably be covering the flooring with carpet at some point. I'm still thinking about trying the DAP spray foam, which supposedly doesn't expand as much as the polyurethane foams. Do you think this is an acceptable approach?

Nope, that is going to make a bulge in your floor.

this is what you need. anything else and you might as well pull the floor up. Are you sure the parquet isn't buckling slightly, leaving the hollow spots?


http://www.hardwoodindustry.com/pages/405417/index.htm

no, the hollow spots aren't buckling at all. The individual pieces are just not attached to the floor anymore. I'm concerned that if I use an adhesive, it may not fill the entire gap, and I'll still have the hollow spots (not as big an issue once I carpet, I suppose). I'm also still confused about what I can squeeze through a 1/16" opening. Thanks again for any pointers you might have.

Did you even click on the link I provided? Anything else is a band-aid, or could cause it to not be repairable.

Yes, I did follow the link you supplied, thanks. Not being a contractor, it probably wouldn't be a great investment for me (didn't see any pricing info, but I'm guessing it's not cheap). I really do appreciate the info and advice you provided, though.

I decided to gamble on a few spots, using the DAP expanding foam (the newer version with less expansion). It seems to have worked just fine. I filled in the holes afterward with wood putty, and so far, so good. Perhaps not the best approach, but in a pinch, it did the job.