Hello,
I just finished my basement and put in some engineered hardwood around my bar applied directly to the concrete with glue. I installed it over seam in the concrete that was slightly raised up. This has caused some spots of the flooring to raise up and not adhere to the concrete. Now if you step on one of them, the floor pushes down, sticks to the concrete and pops back up when you step off of it causing a very annoyingly loud "POP" sound. Is there a procedure and tool that can be used to drill a small hole in the flooring and fill the void with a liquid of some type which would harden and keep the floor from collapsing in these spots? Other than this, the rest of the flooring is stuck down like it should be. Please let me know what if anything can be done short of ripping it out and doing it over. Thanks much!

You can try using a large horse syringe and filling the void with adhesive. It's not easy to force the adhesive down in there to fill a large void like that. A hardwood flooring supply, has syringe kits for injecting epoxy, but for a small void ( the epoxy sets too quickly to fill a large void). I have heard of guys injecting Deco Rez, and filling voids, ( apparentely it flows into a large void easier than adhesive will), I havent had to try that

All that said...I can tell you know the bottom line, by your post. Anything you do at this point is just a mickey mouse band aid. Without tearing out the floor and performing the correct preparation on the high sections of the concrete.

Also on a below grade installation, I would have sealed the slab first ( Bostik MVP or Mapei Planiseal). Hopefully that doesnt come back to haunt you.

We use the glue injection kits on a daily basis in our service department, and dont find them to be a bandaid solution. While it is important to make sure the substrate is flat, even minor irregularities can cause that movement and popping sound.
Both flooring and glue manufacturers recognize the injection method of correction to be a satisfactory solution.
We always explain to clients that this could be necessary (before we start the project) so there are no surprises down the road.

Yea, don't see any long term problem with using Dri-Tac to repair that...fairly common, and shouldn't need to tear anything out if done right.

Like you mentioned, it is important to make sure the substrate is flat. It sounded to me that the high seam in the concrete was not a typical "minor irregularity" that a professional would feel comfortable installing over. It sounded to me that the hollow area is extreme. Maybe I'm reading between the lines too much.

I realize that the epoxy injection is sucessful in "minor" situations. I dont understand why your service dept. uses this on a "daily basis" . Do the guys use a 150 pound roller on gluedowns ? I use one on all gluedowns and dont have this issue, on "minor irregularities".

I understand your reasoning behind mentioning the possibility of injecting to the consumer. You must mention this once the job is sold, ( your trying to put out a fire before it starts, being that you use this technique daily.) I know that if I mentioned that to the consumer, before starting installation, red flags would go up right away, in the consumer's mind. And after the install they would be crawling around knocking for hollow spots I know that if I mentioned that to a consumer, (in my area), before the job was sold, I would lose the job. Either way it just opens a can of worms IMO. I just dont feel injecting should have to be used on a daily basis.

There is usually several discussions between our sales department and potential client before agreeing to do an installation. We have found that educating our clients prior to drawing up a contract makes for a more harmonious relationship.
Some of the points discussed are humidity controls and what the lack of them may entail, maintenance procedures to follow after installation, floor protectors, etc.
Sometimes when a client comes in to discuss a project, and we spend the time educating them, they are amazed and usually sign the contract before leaving the showroom.
The usual comment is : why doesn't everyone tell us these things.
As far as using glue injection on a daily basis, remember that we are a larger company doing an average of a dozen installations per day. I have 18 crews I am responsible for, and there are so many site variables to deal with the "shoot" happens
A large part of our work involves large production builders and it is their responsibility to provide proper sub-floor and site conditions.
When this doesn't happen, the site supers direct the installers to proceed, knowing that we can correct minor issues down the road and not affect closing dates. We are usually on site only 2-3 days before closing so there really isnt time to stop an install and chat about corrective measures over a leisurely coffee.

I think I can debate this issue till I'm blue in the face, I'll just let it go

Thanks to everyone for their input. I see I sparked some healthy debate on this issue. The spots I have with voids are not large, the biggest one I think is about 15 inches accross, the others are about 6 inches or less. Total
distance off the floor at worst would be 3/8". I am the home owner and this is the first time I have installed hardwood flooring, I learned my lesson for sure, I would have knocked down this high spot if I had known it would casue this issue, I simply did not do enough homework and did not suspect it would be an issue. At this point I see my only option as trying the epoxy filler method as I don't have the funds to rip everything out and do it again. Just got my basement done including carpet and the all important Football season is upon us. I appreciate everyone's input and understand everyone's point of view on this subject. Again, thanks to everyone for their replies.