Is sound insulation according to DIN 4109-1 sufficient for a mid-terrace house?

Hello everyone,

I am considering buying a mid-terrace house in a new development area. In the construction description under the category sound insulation, it is explained that only the legally required minimum standards according to DIN 4109-1 are met. Furthermore, according to the construction description and thus according to the developer’s written statement, the sound insulation according to 4109-1 is significantly below a high level of sound insulation that would typically be expected in terraced or semi-detached houses, and noises from other mid-terrace houses can be heard clearly.

According to the homebuilders' literature, the minimum requirement according to DIN 4109-1 for sound insulation is described as "loud speech understandable, loud music audible," and impact sound insulation as "walking noises disturbing." In addition, DIN 4109-1 is discouraged according to the book and reference is made to VDI 4100 (2007).

Accordingly, I assume that the noise I generate (speech + footsteps + TV music, etc.) can be heard in the adjacent mid-terrace house by neighbors and I can also hear my neighbors? Would that mean that my neighbors would already be disturbed if my TV runs in the evening until midnight and they go to bed at 10 p.m.?

I am waiting for feedback from an expert and wanted to first get your opinion and experience here in the forum about whether DIN 4109-1 sound insulation would be a deal breaker for purchasing the mid-terrace house, especially since I often work from home and my neighbors might overhear my confidential conversations and vice versa.

Attached are the key data:
Ceilings L'n,w <= 41 dB
Stairs: L'n,w <= 46 dB
Party walls ground floor: R'w = 63 dB
Water installation L<= 27 dB (A)
Other building services L<= 30 dB (A)

Partition walls between mid-terrace house walls = reinforced concrete walls, thickness each 12 cm. Between the walls, separation joint panels, thickness 4 cm.

I hope I am somewhat exaggerating my concern and would appreciate feedback, whether positive or unfortunately confirming my assumption.

Many thanks in advance and kind regards
Twist

Partition walls between terraced house party walls = reinforced concrete walls, thickness 12 cm each. Between the walls are separation joint panels, thickness 4 cm.

Each house has its own "outer wall" and between them are the separation joint panels. That already makes me very relaxed.

when I often work from home and the neighbors overhear my confidential conversations

That doesn't happen anyway.

sound insulation according to 4109-1

That is the minimum sound insulation for rooms requiring protection = bedrooms etc.

a deal-breaker for buying the terraced house would be

How sensitive are you? You are getting a "normal" terraced house as it is built dozens of times daily. But even in detached single-family houses, there are forum members for whom it is too loud. Would you like to say which developer it is?

Hi Benutzer200,

thank you very much for your quick response.

Each house has its own "exterior wall" and between them are the joint panels. That already makes me quite relaxed.

So are my concerns somewhat exaggerated? That the walls are "thin" and you can hear spoken words? As a layman, I am also referring here to a builder's manual that advises against DIN 4109-1, and the construction description also states that noises from other terraced houses are perceived more strongly. That sounds like a legal delimitation of services as a safeguard for the developer.

That is the minimum sound insulation for rooms requiring protection = bedrooms, etc.

But is sound insulation enough when higher requirements according to DIN 4109-5 or VDI 4100 are already met as standard in other terraced houses, which the developer himself mentions in the construction description?

Would you like to say which developer it is?

Gladly via PM

Best regards
Twist

Gladly as a PM

Unfortunately, I have written too few posts for a PM.

We have just moved into our mid-terrace house built in 2000. According to the construction description, partition walls are made of 17.5 cm calcium silicate brick, 4 cm air layer, and then the neighbor’s own 17.5 cm wall again. Unfortunately, nothing is mentioned about the sound insulation standard. There is no basement.

We expected basically not to hear anything, but were somewhat disappointed. There seems to be a sound bridge to the right neighbor because we perceive structure-borne sound, which includes: - footsteps, but apparently only from certain spots/rooms (one of the residents seems to have quite a heavy heel strike). - a few times a day a dull, short rumble as if something heavy fell on the floor.

Other than that, we hear absolutely nothing. No conversations or other everyday noises like washing machines, dishwashers, or similar.

Of course, it would be great if there were no structure-borne sound transmission, but it is really tolerable and, compared to our previous apartment built in 1978, luxury.

I also work permanently from [HO]. The office is right next to the bedroom and my girlfriend currently has time off and I am working. The interior walls are only made of drywall and you can’t hear conversations. You can perceive them but not understand them. So the neighbor definitely won’t hear anything – don’t worry.

Hi Hutchchinson,

thanks to you too for the quick feedback!

Already some opinions that contradict my concern.

According to the building description, partition walls made of calcium silicate 17.5 cm, 4 cm air layer, and then the neighbor's own wall again at 17.5 cm.
Unfortunately, nothing is mentioned about the sound insulation standard.

Your walls are a bit thicker but made of a different material (calcium silicate 17.5 cm vs. reinforced concrete 12 cm). It is nice to hear that you have soundproofing.
I am still waiting for the expert's feedback.

- A few times a day a dull, short rumble as if something heavy falls on the floor.

That could be the dog or an overfed cat jumping on the floor.

Best regards
Twist