Insulation of a detached semi-detached house - experiences?

Hello everyone,

I am interested in purchasing a currently detached house that is planned as a semi-detached house. The shell is already built. What is unclear to me is the insulation of the house wall facing the not yet built neighboring house, given the fact that it is completely uncertain whether the second semi-detached house will ever be built.

The investor wants to insulate and plaster the house, which is declared as KfW55, on the questionable wall with the soundproof insulation usual between two semi-detached houses. However, this "insulation" is only 6cm thick. The insulation on all other walls is 16cm. I am not an expert, but I assume that in this way I will get significantly worse insulation and, in my understanding, the house cannot be a KfW55 house. Insulation with the 16cm would lead to an overbuilding. The neighbor had originally assured the investor to sell the land for the second half as well, but then backed out because he no longer wants to reduce his garden so much. I am now uncertain because I a) do not know what to negotiate regarding the insulation and b) have no certainty if a house will ever be built there and especially what design and quality will be directly next to my potential home.

I would be grateful for any advice. Further information regarding the matter gladly upon request.

Best regards,
Moe

Why do you want to tie yourself to so much uncertainty for a lot of money? My advice: stay away

Uh - a semi-detached house is planned (with building application and everything) and then it's not built after all? Does the building permit still apply (boundary development)? Whether it will still be a KFW 55 house should depend on the corresponding calculation. And the calculation on the development. So the question should be answered to you in writing by your developer with all the information and calculations. Apart from that, you will have no influence on the neighboring development.

Very suspicious construction project. "Has assured" - and then you already start with the first half?

I am not an expert, but I assume that in this way I get a significantly worse insulation and, according to my understanding, the house cannot be a KfW55 house. Insulating with the 16cm would lead to an encroachment. The neighbor had originally assured the investor to also sell the land for the second half, but then backed out because he did not want to reduce his garden that much after all.

I think you don’t have to be an expert to see that in this situation they are probably looking for a fool.

First of all, I have to wonder about some people here. At least in NRW, a semi-detached house is considered an independent house. And each of them has its own building permit. And here in our area, you quite often see such semi-detached houses.

Our house is also built as a border construction; but on this side not with a double layer, rather with thicker stones and smoothly plastered. The house has stood since 1995. Next to it is a garden for all "eternity".

The "insulation" between the semi-detached houses is actually only for separation.

If you are really interested in the semi-detached house, get an independent building expert on board. Not only because of this wall, but because of the rest too.

Regarding b); is there a development plan for the area; if yes, what does it say? Often there are some specifications; but in principle, you are quite free in the design of your semi-detached house.

And what concerns do you have regarding the quality of the non-existent semi-detached house?

I don’t believe that a "fool" is necessarily being sought. The builder or investor simply made the mistake of starting construction on the first half of the property without a binding commitment from the neighbor for the second half. The building permits for both halves are to be viewed separately. For prospective buyers like me, there is now the chance for a nice detached house. I am looking for advice on how to proceed. I will speak with the owner of the large adjacent property to see if he might simply sell me one more meter along the entire length of the property. Then he would still have a large garden, and I would have security that nothing uncertain will ever be built next to my house. The development plan only requires the same roof shape and dimensions—nothing else. Alternatively, I could try to negotiate a right of first refusal with the neighbor if he is currently unwilling to give up even a part. In any case, I need to clarify with the neighbor how a solution for insulation would look. In NRW, the insulation may not exceed the boundaries of the property. But if I insulate with 16 cm, I exceed the boundary, which means a building encumbrance that I would have to remove at my own expense if the neighbor eventually sells and I do not have a right of first refusal.