Ensure compliance with soundproofing requirements when accepting a condominium unit

Hello forum,

after quietly reading and learning for two years, I am now turning to you with my own question. I have purchased a newly built condominium from the developer. Completion will be in August 2022. The building has three floors and a total of nine units. The construction performance description specified decibel values and standards that are to be met by the installed soundproofing. If I understand correctly, after acceptance and handover of the condominium by me, the burden of proof reverses if I suspect a defect somewhere. If I now suspect a defect during acceptance, would it be the developer’s responsibility to prove to me that it is not present? Specifically: at acceptance the building will be unoccupied and quiet. Compliance with the decibel values, due to lack of measuring equipment and noise, may not be verifiable by me at that moment. Can I blindly suspect a defect and force the developer to prove compliance with the construction performance description? Or will he likewise "blindly" assure me that the construction performance description applies and was complied with? Do I have to wait until after all parties have moved in and then, if there are irregularities, check myself how loud the communal noises penetrate/escape?

Thank you, Rosinanthe

Do I have to wait until after all parties have moved in and then, if there are irregularities, check myself how loud the communal noises penetrate/sound out?

Thanks,
Rosinanthe

Yes.

How do you imagine an alternative? Employees of the construction company go into the remaining apartments and play football there with loud fan chants?

Yes.

How do you imagine an alternative? Employees of the construction company go into the other apartments and play soccer there with loud fan chants?

Wait, I'll explain it to you. Two people are enough. One walks through the neighboring apartment and mumbles a magic spell. The other listens and expresses doubts about the compliance with the construction specifications if he understands the mumbling.

Does anyone have an idea how to check or verify the soundproofing implementation during acceptance, before handover?

Does anyone have an idea how to verify or prove the implementation of soundproofing during acceptance, before handover?

Have the soundproofing certificate according to DIN 4109 given to you - this is one of the documents that must be submitted with the building application. Then check whether construction was carried out according to the specifications and plans. It's quite simple – for example, during acceptance, knock open walls and check ;) .
Of course, that doesn't work. It should have been done during construction. Therefore, you can only rely on the documents and see if there are any inconsistencies.

You cannot check that yourself. During the construction phase, someone should have ensured that everything was built correctly regarding the issue of [Schallbrücken] and so on. In the finished state, an expert must come who conducts tests with appropriate equipment. But that does not cost just a few hundred €.