I bought nearly 2000sf of floating click-n-lock floor. It came in 3 sizes, 4ft, ~3ft, 18" and 1ft lengths. We purchased very good underlayment at $38 per 100 sf. After the first 1000sf I stopped installing and called the manufacturer. Every step squeaked. I could even hear my 15lb shiz-tzu squeak the floor. Previously I had Kahrs floating floor and it did not squeak; but it was installed in 2001 with 8" wide 8 foot length pieces that were glued together(not to the concrete slab). I liked it but a broken fridge line ruined it so we had to replace the floor. Since it didn't squeak I didn't expect this new floor to. The manufacturer said it was defective wood, refunded me all the money for the wood, took back the unopened boxes and told me to throw out the 1000ft I had laid. I don't believe it is defective. I think this is what you get with this stuff. So after consultation, we decided to glue our floor down. We pulled up the floated floor, bought some more wood and had a professional re-install(with very good adhesive/glue). It doesn't squeak but we don't have that soft feel of floating floor that I liked. Also, I believe they used a urethane adhesive and it did not smell at all. Absolutely no glue smell. If you don't like the creaking, be careful with floating floor.

My husband and I own a radiant heating business in California. In our first home, we put a floating laminate floor over the radiant and it worked out great. In the new home we are building, we will probably use a floating engineered wood. I found a website about installing wood floors over radiant heat. The link is at the bottom. What they say is that for radiant heat, engineered wood is more dimensionally stable than solid wood flooring. Also, they say that floating the floor is best because it tends to move as a unit to help accommodate moisture content changes. What ever you decide to do, make sure you acclimate the flooring first. Also, make sure you run your radiant system for at least 72 hours before installation to make sure the slab is dry. Here is a link that might be useful: installing wood over radiant heat

Update: I attempted to email the inspector with my questions and such but he did not respond. The builder had told me if I had questions, to ask the inspector, but upon calling an inspector myself to ask about fees and doing an inspection for me, he indicated that they are not supposed to talk to anyone about the issue that did not actually hire them. Since the builder hired them and I did not, then the inspector could only talk to the builder. Once I understood that, I got back with the builder to see where we would go with this issue. Thats when I found out that they had noticed another failure just like mine in a spec house that they did. Same sub did the work. They went in and discovered that the wood floor came back up easy so the planks could be reused, so they redid it using different glue. So now they are doing mine. As I suspected, all of the wood planks have come up very easy with no breakage. There are some spots where the dri tak had held that caused breakage of the planks, but lucky most all were in one confined area since I had previously told them to stop using the dri tak as it was not in my opinion the proper repair. They are using a glue called rocket 7000 i believe. It is a different glue than what he used before. When the planks are pulled up, there is squished glue on the plank and on the concrete, but it is tacky to the touch but does not come off unless you scrape it off, which then it does peel off to some degree. Maybe it is supposed to be that way. Not sure as I have not got into any deep discussion with the builder or the sub about it. I just stay out of their way and am glad they are doing this at no cost to me. Builder and sub have stepped up to the plate to correct this, but it did take some work on my part and some bull headedness on my part. Most of the planks are being reused with some being replaced with new since they can still get them. Any comments or advice?

Oh dear. Noise abatement requirements with hard surface flooring over light weight concrete (aka "gypcrete"). And you only have enough room for 6mm worth of acoustic insulation. Hmmmm. You are getting into expensive territory. First check what is ALLOWED by the HOA/Condo board. They will have ratings that will tell you what you have to MEET or exceed with hard coverings. Secondly check to see if the acoustic glue underlayments will even grab gypcrete. Most things HATE gypcrete. I mean HATE. There are many high-quality glues that do NOT grab gypcrete. And the one's that do, can be nasty. But don't worry. Being in California means you can't purchase anything that violates CARB compliance - unless you order it over the internet (ahem...best to stick with brick and mortar point of purchase for stuff like this). And just for fun, not all wood floors can be floated and not all can be glued. And not all glues grab gypcrete...see where we are going here? And then there is the noise abatement that MUST be addressed BEFORE you go any further. Without those numbers, you are flying blind and so are we. In the cork industry, I NEVER got my 6mm cork underlay to pass a SoCal condo boards requirements. My customers ALWAYS had to go 12mm with a wood floor (of any kind). You can get some decent sound reduction with mass loaded vinyl. But it is expensive. It is very thin and very expensive. And vinyl does NOT like sitting underneath wood. But it depends on the mass loaded vinyl product. And QuietWalk Plus is a product that is relatively thin and yet has some of the same acoustic insulation as 12mm cork underlay. It will save you the height at least. It too is not cheap. https://www.mpglobalproducts.com/flooring-underlayment/products/quietwalk-plus/sound-rating/