Fixing cracking sound in new floating floor

[pete1982]

I recently installed a tongue-and-groove floating bamboo floor over a concrete subfloor and almost immediately it began making an unbearable cracking sound whenever I put my foot on it.

- I left an expansion gap of 1 inch around the floor with no pinch points.
- I used PVA glue to glue the boards.
- The cracking is not at a specific point - it is all over the floor.
- The concrete subfloor curves gently over a length of about 7 metres (with the height of the curves in the middle of the room). There is little other significant unevenness - where I noticed gaps when putting the boards down I used extra squares of underlay to fill them.
- I also used a cheap 3mm all-in-one damp-proof underlay from B&Q.
- We left the floor for 6 months to see if it would settle down, but no luck...

I have 3 questions I need help with!

Is there any way of addressing this short of pulling the floor up?

If I need to pull the floor up what is the best way of doing so to avoid damage?

When relaying the floor is there a better type of glue I can use or other precaution I can take to stop this happening again?

 

[WoodYouLike]

Your concrete subfloor: was that of good and sound quality, without any powdery surface? (Like badly done screed on top of it?)
If you have left it for 6 months it shouldn't be down to 'settling in' any more, that's normally done within the first 2 - 3 weeks.
My thinking is, specially since you call it 'cracking' sound, when you walk over it there are loose bits, dust, particles of the concrete between the underlayment and the underfloor.

 

[pete1982]

We had the floor checked out first by a specialist contractor. There was no dampness and no powdering. We actually painted the subfloor with a watered down PVA mix prior to putting the underlay down specifically to address that. Also we vacuumed thoroughly.

When you put heavy weights on the floor the cracking 'goes away' and the floor feels a lot more solid to walk on. Don't know if that helps the diagnosis any.

 

[WoodYouLike]

Your Bamboo boards: short lengths (90cm) and narrow widths (90mm)?
Than the slight unevenness in combination with the many joins could cause continuous movement and the cracking sounds.