Oh wow, I really do hope that is the case, echoflooring! How does one determine if the hollow sound is due to dips, or if it is due to adhesion problems? glennsfc, our substrate was flat to within the manufacturer requirements. The installers used a laser, and leveled areas with the appropriate concrete filler. If we were to use the injection technique to fill, where do we stop? There are seemingly hollow spots in MANY areas, not just one or two. There are so many spots - I'm guessing 30 or more.... thoughts?

Most of the spots stuck after we put a maze of heavy objects on the floor. Just one or two places that bug me now. The floor installer owner is going to come by for his payment and I'm going to ask him to replace a few boards then. One board had a split in it, and the installers cut out the part that was sticking up and filled with wood filler, about 3"x1". It looks bad and is right in front of the fireplace where it is really noticeable.

They will say that it is a site related issue - that is what they are saying - "CLIMATE" - which they may claim they have no control over, only the homeowner is responsible for that. Wood has predictable behavior. They should, since they are professional installers, have all of the documentation regarding the ambient air conditions before and during installation as well as the rh/calcium chloride test results (whichever one they performed and you paid for - hopefully) and ph of the concrete - most professionals include that documentation or report with the final invoice to the end user and kept as long as the floor is under the manufacturer's warranty. Technically, if you wrote 2 checks, it is your responsibility to make sure that was done.

Oh dear. That's what I thought. Here's the skinny on 'prep'. Prep is the UGLY stuff that NO ONE sees and NO ONE knows to ask about...nor do they usually OFFER the ugly stuff in their quotes. The ugly stuff is expensive. And in the past they have quoted it and they have lost jobs to lower bidders who did NOT offer prep. Over and over again the 'good' companies offer quotes on prep and time and time again they LOSE the jobs. So they have started to work like everyone else. To stay in business they drop the preparation quotes. Which is how they get jobs....because their bids are now 'in line' with the companies around them. Subfloor prep needs to be paid for. And the company that promises it must deliver it. The basis is, you pay for it = you get it. This company has not quoted nor were they paid for prep work. Sadly (oh so sadly) you were the one who 'got what you paid for' (not meant in a mean way). So...to get preparation done, you will need to pay for it. An upstairs preparation costs = $1-$3/sf for a bit of sanding...a bit of levelling...a bit more sanding. The concrete slab can require $2 - $5/sf for preparation...and in this case the sealant will need to be paid for as well. A slab that is in good shape that is nice and flat, that only needs a good scrub to get a bit of bite to it = $2/sf. A concrete slab that needs a good cleaning (may have old carpet glue all over it) and plenty of grinding and plenty of patching (Self Leveling Compound = SLC) and more grinding can and will cost $4+/sf. And these numbers are why they didn't quote it. The upstairs = $2/sf x 609sf = $1,218. The downstairs concrete (just for fun we'll use $4/sf) = $4/sf x 694sf = $2,776. The prep alone *should have been quoted at $4,000. Their quote should have been more than $25,700. ***At this point, assuming you can prove they were all wrong on all things, they owe you removal of the improperly installed floor. They must replace with 'like for like' subfloor plywood that was there BEFORE they arrived. Be aware that you *might be required to pay the extra $4,000 for the subfloor preparation that you did not pay - that needs to be done...you may not. It depends on how good you are at negotiating. If they won't do this voluntarily you will be required to pay for the NWFA Certified Inspector to come out and document what you spoke about over the phone. And then you present the findings (but do NOT hand over the document...SHE who pays for the report OWNS the report). The findings will push them to do the right thing. Hopefully they will come to their senses before you have to spend several hundred dollars on the Inspection.