Partition wall terraced house

Hello,
we are building a mid-terrace house and have the following problem:
The right neighbor is already building, so the execution of the partition wall to the neighbor is clear. 17.5 cm KS plus 2 cm Odenwald board or mineral wool. So it results in KS - 2x 2 cm Odenwald board - KS. According to my information, this is the standard execution.
However, the left property will not be developed in the foreseeable future! Therefore, the question arises how the left wall (which is now initially an exterior wall) should be constructed so that the wall is protected from weather and insulated. Our builder’s suggestion is also to use a 17.5 cm KS stone plus 6 cm insulation boards plus plaster, built on the property boundary. This is supposed to be the optimal solution regarding moderate thermal insulation until the neighboring terraced house is built. The insulation should then remain if construction takes place on the left.

Is that sensible? Are there any disadvantages regarding sound insulation towards the neighbor if you use the 6 cm insulation boards compared to the Odenwald boards or bituminized soft fiberboards as they are also called?

When using the 6 cm insulation, we have already been informed of an additional cost of about €2000, but I do not yet know the exact amount. The left wall has an area of about 100 m². Does anyone know how the 2 cm Odenwald boards compare in price with the 6 cm insulation boards? Because only if the insulation boards are significantly more expensive than the Odenwald boards can I explain the surcharge. The Odenwald board would then no longer be needed.

When the neighbor eventually builds, will the Odenwald board be applied to our plaster or how is the execution likely to be?

Perhaps someone here has had a similar situation before.
Thanks in advance!

Hello Kai,

...Odenwaldplatte

I cannot make anything out of this term at all ...but the following

...The proposal from our builder is also to use a 17.5 cm KS stone plus 6 cm insulation boards plus plaster, built on the property boundary. This is supposed to be the optimal solution regarding moderate thermal insulation until the neighbor’s row house is built. The insulation should then remain if there is construction on the left.

is a good solution!

If a neighbor then comes later – no matter when – he simply builds his KS wall plus 2.0/3.0 cm ventilation onto your party wall. The only catch with this approach or a DH solution, if only one partner is involved, is that you lose _some_ WF according to the current thickness of the party wall plus insulation.

Kind regards

Hello, first of all, thank you for your quick response. I found the term Odenwaldplatte on the internet, alternatively, bituminized soft fiberboard is also used as a term. I realize that we lose some WF, but we can manage that. Can you justify your opinion, can you say something about the topic of sound and price (insulation boards compared to "normal" intermediate boards)? What do you mean by ventilation, really "air" or do you mean some kind of filling material?

Hello Kai,

...I understand that we lose some WF, but we can live with that Can you explain your opinion, can you say something about sound and price (insulation boards compared to "normal" intermediate board)? What do you mean by ventilation, really "air" or do you mean some kind of filling material?

With KS, soundproofing is not an issue if the "rules of the game" are also followed on the other side; and yes, I really meant air.

Prices are a tricky subject we recently encountered a similar situation. We calculated €2,300.00 for a 24 cm KS wall plus 16 cm ETICS, for a building with dimensions 8.0 x 11.0 m.

Best regards

Hello, I need to ask for clarification, is the €2300 including the KS stones or only for the 16cm ETICS? I am expecting "only" an additional charge for the 6cm insulation boards, especially since the normally installed 2cm soundproofing board "does not apply" and therefore should be deducted. What should then still be applied on the 6cm ETICS, is a base plaster sufficient?

Hello Kai,

I need to ask more precisely, is the €2300 including the KS blocks or just for the 16cm ETICS? I only expect an additional cost for the 6cm insulation boards, especially since the normally installed 2cm soundproofing board "does not apply" and should therefore be deducted. What should then still go on the 6cm ETICS, is a base plaster sufficient?

No problem, it's my own fault for answering too briefly

We usually install a 17.5 cm KS as a party wall when the second partner of the semi-detached house is also on board. In the mentioned example, in my opinion, this is not the case in the long term because the second plot is a bit more complicated due to its layout. Therefore, at our customer's request, we planned a 24 cm KS wall plus ETICS, motto: better safe than sorry; the loss of living space - as requested by our customer - is not an issue. Therefore, the price I mentioned includes the additional cost from 17.5 to 24 KS, the 16 cm ETICS, and the synthetic resin plaster.

Kind regards