owed soundproofing terraced house new build

Do you have a source for that! As far as I know, this is not the case, but townhouses can also be built that share a wall. In most cases, this is probably no longer done, precisely because of the noise issue. But it is possible and, to my knowledge, does not lead to the townhouses becoming an apartment building.

Hello, I do not have a source for this. But I have had cases where a semi-detached house became a two-family house and was treated like an apartment building because the property could not be divided for this reason. The sound insulation corresponds exactly to the value of a partition wall of an apartment building. (R`w = 56 dB). With a cavity wall, it would improve by a maximum of 2 dB with perfect installation (realistically rather 1 dB).

According to my research, however, the minimum requirements do not correspond to the recognized rules of technology, which raises the question of whether 62dB or 67dB sound insulation is required.

Beware, "recognized rule of technology" is not the same as "state of the art." Technical rules are usually threefold.

Hello, I don't have a source for this. But I have already had cases where a duplex became a two-family house and was treated like a multi-family house because the property could not be divided for this reason.

But that's also something different! Although in this case, the whole thing could have then been converted into single-family houses in condominium ownership. Which, of course, is basically nothing other than a two-/multi-family house built side by side. However, this only has something to do with the fact that the property was not divisible there and it would have become difficult with the ownership arrangements.

But if the properties are divided, two terraced houses can certainly share a wall (party wall), but this often has acoustic problems. The important thing is simply that one's own house stands on an independent piece of land.

I am currently on the move, but just to clarify briefly. It is a TERRACE HOUSE divided by a PATH with corresponding exclusive ownership of the house and land. Therefore, I would think that a physical division is probably unproblematic.

Now a bit more extensive:

Not only the sound insulation would worry me, but also the purchase or construction contract.

Strictly speaking, you are right. In the purchase contract, the object of purchase is designated as "co-ownership share of the property connected with the special ownership of the apartment located on the left side of the row house line (with row house character) along with ..." I had checked this in advance, but regarding the requirements for sound insulation, that makes no difference. However, since the planners/architects are a complete disaster, it is quite possible that they oriented their planning on the requirements of a multi-family house.

In my opinion, you don’t reach the value of 62 with a drywall construction either.

That is naturally the relevant point for me. According to the site manager, two sound insulation reports have been obtained so far, confirming a value of 62 dB. However, I have not seen them yet. Is the value of 62 dB the relevant one, or in other words, am I wrong with the 67 dB?

"recognized rule of technology" is not equal to "state of the art". Technical rules are usually three-valued.

What does "three-valued" mean? In the purchase contract, the contractual object is to be constructed according to the recognized rules of building technology. Meanwhile, I am wondering whether this is even fulfilled with a single-shell construction.

is a condominium (WEG) split terraced house with corresponding individual ownership of the house and land

Then, in case of doubt, the less strict sound insulation values for the construction of apartment buildings apply… double party walls and soundproofing strips are also not required there! This is one reason why developers prefer to build according to WEG because it is cheaper for them.