What applies to sound / noise in private new construction?

Although the DIN standards are almost always considered recognized rules of technology and the legislator assumes that this presumption generally holds until it is disproved, the DIN 4109 is the typical example of a standard that is not considered recognized rules of technology! There is also a court ruling on this, you would have to google it.

I have read that DIN 4109 is outdated and according to the BGH, one should refer to the recognized rules of technology, which correspond to VDI 4100 Class 2. This is significantly higher than DIN 4109.

Do you have a source for that? So far, I was familiar with the following:

[*]Construction defect if only the values of 4109 are met [*]Values of the supplement 2 to DIN 4109 as minimum requirement [*]VDI 4100:2012 SST I + II only if the building description / the exposé conveys a "high-quality" impression of "upscale living". This is rather rare in single-family homes, more common in multi-family residential buildings

The values of VDI 4100:2012 SST II will probably be met by very few single-family homes.

Bosy writes:

The minimum requirements for sound insulation in building construction are defined in DIN 4109 and deal with sound insulation between separate apartments. Through its introduction by building regulations, it has gained public-law significance. [...]

In DIN 4109/A1:2001-01, the values for permissible sound pressure levels in noise-sensitive rooms from technical building equipment are described. These values are regarded as recognized rules of technology (aRdT) and apply whenever no further agreements for increased sound insulation have been made.

One should be aware that DIN 4109 only defines minimum requirements! However, if these are not met, the construction is defective. Those who expect more must justify it somehow. Here, the legal discussion states that increased sound insulation does not necessarily have to be explicitly agreed upon (if so, even better); it can be sufficient if the exposé mentions "upscale" and similar terms.

, please do not just remove the URL (source reference), but then remove the entire quote.

To the OP:

You seem to have a noise problem: Have you measured the noise level? The various smartphone apps deliver surprisingly good results, and while you can’t measure absolutely accurately (real noise measurement is tricky and very complex), you can easily compare whether one house is really louder than another.

Noise is something extremely subjective; not only does everyone perceive the same noise differently, but you can’t really compare noise yourself.

Our new building also feels louder than the old house. But in reality, it is not, because, for example, any flow noises from heaters are missing. These used to drown out outside noises in the old house, and at the same time, over time, you no longer noticed them. In the end, you thought you heard total silence.

In the new house, this "background noise" is missing, and suddenly you notice outside noises that you never heard before. So the house feels louder even though it is objectively 1-2 dB(A) quieter.

First try to find out what exactly is going on with you. A standard phone with one of the usual noise measurement apps should give you values around 20 dB(A) inside the house at total silence. Compare this with other houses and apartments to get a feeling for whether you really have a real noise problem or if the new soundscape just seems strange to you.

Best regards,

Andreas