Soundproofing in terraced houses: Interpretation of the building description

Hello everyone,
I hope I have come to the right category here.

We are considering buying a terraced house from a developer. Construction has not yet started. It is a new house type from the developer that has not been built before.
We found a point in the construction description that we stumbled over, the topic of soundproofing.

"The following requirements for airborne and impact sound insulation or sound pressure levels between terraced houses are met:
Ceiling: Ln, w less than 41 dB
Stairs: Ln, w less than 46 dB
Party walls: Rw less than 63 dB or 67 dB
Water installation: L less than 27 dB (A)
Other building services installations: L less than 30 dB (A)

Minimum building code requirement according to DIN 4109-1 fulfilled
Increased sound insulation DIN 4109 - Part 5 not fulfilled

Airborne sound insulation: soundproofing values fall significantly short of the proposals for increased sound insulation
Impact sound and insulation go significantly beyond this
Noises from other terraced houses are also perceived significantly louder during daily use
The difference between impact sound levels of 41 dB and 46 dB is also perceived as a noticeably louder noise by an unbiased user
The agreed soundproofing remains behind what is usual for terraced houses, which would have been expected"

Do I understand correctly that the soundproofing between the houses is rated as very poor, even worse than comparable terraced houses?
Can someone tell me how I should interpret the dB values (comparison values to other terraced houses)?

Thank you very much for your help!

BAUSTOLZ houses? Sounds familiar to me. I cannot assess this from practice, but normally "regular" developers build according to Part 2 or Part 5 according to the new DIN.

BAUSTOLZ houses?
Sounds familiar to me. I can't judge from experience, but normally "regular" developers build according to Part 2 or Part 5 of the new DIN.

Exactly... Experiences with this developer are also very welcome!
Ok, I will research the DIN standard again.

Exactly... experiences with this property developer are also very welcome!
Ok, I'll research the DIN standard again.

We almost bought it. Many things about the BBS bothered me a lot. Due to lack of alternatives, we almost pulled the trigger.
WEG, soundproofing, no changes possible at all, no basement windows, partly no screed. Thin walls.

So I imagine it as pretty "loud" because of the soundproofing.
And the price advantage with the Baustolz advertising doesn't really exist... way too expensive for the build quality.

Hello,

Was the house eventually purchased and if so, how is the perceived noise level inside the house? There should actually be quite a few of the Baustolz houses but unfortunately I can find little public experience about them.

Thank you

Hi,

yes, you understood that correctly. The construction description basically states quite openly that the sound insulation is below the level that one would actually expect from terraced houses nowadays. They do meet the minimum legal requirements according to DIN 4109-1, but that really is only the absolute minimum.

Especially the point about airborne sound insulation between the terraced houses is critical, because it's about how much you hear from the neighbors' everyday life, e.g. conversations, TV, or music. If only an Rw < 63 dB (or even < 67 dB, which is worse) is achieved, that's roughly what you would expect from cheap apartment buildings from the 90s – nowadays people actually want more quiet, and those values don’t provide that. For comparison: values around 72 dB and above would be the target for increased sound insulation.

Impact sound (Ln,w < 41 dB or stairs < 46 dB) is at least okay to good, that's even above the minimum requirements. But that helps you little if you watch the neighbors' Netflix session in the evening.

If this is a new house type and no show home has been built yet, caution is advised. Developers like to write that they comply with the minimum requirements – but that doesn’t say anything about quality and living comfort. You should definitely talk to someone who already lives in a Baustolz house and not rely only on the paperwork.

If you want quiet, better check whether something can be done about the wall construction, or whether you might find an alternative after all.

Best regards