First of all I'd like to apologise for using English but if I want to be as clear as possible in my explanation and my Swedish would not be good enough.
So I am living in Sweden and bought an apartment this summer. On my first night there I noticed huge cracking and squeaking sounds from the apartment above. The building has a concrete structure and is from the 70', so you would normally expect impact sounds from neighbours around but not wood cracking sounds.
I contacted the board of the building and have been put in contact with the neighbours, this process took some time but in short what happened is: the board came to my apartment to notice the noises after what they asked the neighbours to do some fixing. Then they said they were done with the fixing and asked me to go to their apartment to see what has been done (at this point I was still hearing some cracking noises but less intense).
When I entered their place I could notice how squeaky the whole floor was, every step I was taking was making a squeaking noise that you would only hear in a very old house with a neglected wood floor. They showed me how the floor was built (previous previous owners installed it). Basically you have the wood planks that are screwed or glued on perpendicularly bigger wood structures, this wood structure is screwed into the concrete (here is a drawing I made: https://ibb.co/ry7XPcz
), so the whole floor is floating over big screws and there is no isolation in between the concrete and the wood, just air. So as you can imagine, every vibration from footsteps or from the wood cracking is directly sent to my apartment and I can hear it very well.
So my neighbours screwed some wood planks to the bigger wood structure (around like 1sqm) and were pretty happy with it. I tried to explain that it is still cracking everywhere and the best was to act on the root of the problem, which is how the floor is installed, so I proposed to help them financially to put a new floor but they refused. So I talked again to the board trying to understand if this type of installation was normal, to me it seems abnormal to have a wood floor directly screwed to the concrete, it should normally be a isolation foam layer in between the concrete and the floor. But the board said that it doesn't seem so weird and they are not engineers so they don’t know.
That’s why now I am seeking help outside, as it seems no one really wants to do anything about it and I am the only one annoyed with this situation so I would like to know what the law says about it, are there any regulations regarding how a floor should be? For me the best scenario is that they change their floor with an isolation layer but I don’t want to pay for the whole thing, I’d rather sell my place than do that. It’s just that I usually don’t run from a problem, I try to fix.