Good evening.
I'm writing here seeking advice regarding some problems of a new build flat that my partner and I recently purchased.

Floating floor problem:
the flat use a floating floor system with an acoustic absorber layer underneath. The main issue is that the floor is really bouncy and uneven!
When we walk around the flat, the furniture rattle and move under our weight (~50Kg); not considering the washing machine that creates so high vibrations that we can feel them 5/6 meters away (and shake considerably the fridge nearby).
The developer's surveyor and the builders say that it's normal and nowadays all the floating floor system are like this, but in my experience, I've never felt something so weak.
Is it normal for a floating floor system behave like this?

Sound insulation problem:
The flat it's in a building adjacent to a pub. For the part E regulation, the two building need to be separated?
The main issue is that we can hear the pub music from every wall of the pub side, even if we are on the 4th floor and the pub it's only on the ground floor.
Our guess is that being the building connected on the ground floor, the sounds vibrations get transmitted through the building walls carrying the music to all the flats.
We asked for a sound test between the pub and the flats but none was done.
There something that we can do?

I hope that this explanation makes sense 🙂
Thanks in advance for any reply.
Hi - Thanks for getting in touch with us.

I would say in simple answer to your question about the flooring: yes it is common what you are experiencing as it is indicative to the construction method.

A floating floor system is not fixed to a sub-floor so any slight undulations in the sub-floor can result in movement when the floating floor is walked on; so seeing furniture move as it is walked past is the side effect that can't be rectified.

When you mention the floor I see you mention it is uneven: with this do you mean the floor is not flat? If so, there are tolerances for this and they may be required to relay it if it is not flat or level (there are 2 different tolerances for each). I am referring the the NHBC guidelines (LABC is the same if they use them) so I would suggest checking which company provides the warranty. If it is a small developer they may have gone for a more obscure company to save cost. Try and find out as my second suggestion is to get their inspector out to investigate.

With your concern about noise, the only way to determine if it breaches building regulations is to instruct an acoustic specialist. The way they determine this is by placing loud speakers in areas and then using sensitive microphones to determine the decibels. 
It is a specialist check and I think only a few companies in the country can do this. The only issue I foresee is that they would need to place the speakers in the adjacent premises / visit at night when the noise can be recorded.

I do sympathise with your concerns but if I am honest there seems little way round your problems. The construction method of floating floor is not ideal but nothing against building regulations, and likewise there is no regulation to say residential / commercial premises cannot be adjoined. 

Good luck

A link of a noise specialist company is here that we have come across before but there will be others near to where you are based:  http://www.noise-surveying.co.uk/