ᐅ Exterior Wall for KfW 40 (+) Standard: With or Without External Thermal Insulation Composite System (ETICS)?
Created on: 18 Feb 2021 11:23
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Franke86
Hi everyone,
I need some advice. I’m currently planning my detached single-family house. The developer’s standard offering includes 24 hollow bricks plus 14 cm (5.5 inches) external wall insulation (EWI).
Since I want to build to KfW 40 (Plus) standard, they told me I would need 24 hollow bricks plus 18 cm (7 inches) EWI, which would cost an additional €1800.
What would you recommend? Is using EWI still considered "up-to-date," or is it becoming less common?
One advantage mentioned to me is that this creates a cavity wall construction, which offers better insulation and should also help prevent mold.
I also wanted to get some pricing for purely monolithic walls, and I received the following offer (standard is 24 hollow bricks + 14 cm (5.5 inches) EWI):
Which option would you choose, and are these additional costs typical or too high?
Brief details about the house: It’s a detached single-family home with a flat roof, approximately 160 sqm (1722 sq ft) living area, a ventilation system with heat recovery, and district heating for the heating.
Best regards,
Franke86
I need some advice. I’m currently planning my detached single-family house. The developer’s standard offering includes 24 hollow bricks plus 14 cm (5.5 inches) external wall insulation (EWI).
Since I want to build to KfW 40 (Plus) standard, they told me I would need 24 hollow bricks plus 18 cm (7 inches) EWI, which would cost an additional €1800.
What would you recommend? Is using EWI still considered "up-to-date," or is it becoming less common?
One advantage mentioned to me is that this creates a cavity wall construction, which offers better insulation and should also help prevent mold.
I also wanted to get some pricing for purely monolithic walls, and I received the following offer (standard is 24 hollow bricks + 14 cm (5.5 inches) EWI):
- T9 brick, thickness = 36.5 cm (14.4 inches) + €900
- 0.09 aerated concrete block, thickness = 36.5 cm (14.4 inches) + €900
- Hollow brick + 18 cm (7 inches) EWI = KfW 40+ compliant => + €1800
- T9 brick, thickness = 42.5 cm (16.7 inches) = ? KfW 40+ compliant => + €7000
- 0.09 aerated concrete block, thickness = 42.5 cm (16.7 inches) = ? KfW 40+ compliant => + €7000
Which option would you choose, and are these additional costs typical or too high?
Brief details about the house: It’s a detached single-family home with a flat roof, approximately 160 sqm (1722 sq ft) living area, a ventilation system with heat recovery, and district heating for the heating.
Best regards,
Franke86
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pagoni202019 Feb 2021 14:10Snowy36 schrieb:
You can just Google that.I’m confident I can do that.My follow-up question was aimed at obtaining concrete, reliable information and experiences on the topic.
I was already aware that every material and construction method has its pros and cons.
When I express a firm opinion, I want to back it up with credible information that led me to that conclusion.
I’m genuinely interested, which is why I’m here asking instead of just endlessly googling everything.
You know how it is with building—there are no soundproofing requirements for single-family homes. That means you have to deal with it yourself. There is a case in the neighboring forum where a woman lost her life due to the roof construction, along with many complaints from other homeowners. You can find a lot about this if you spend an hour researching.
Building a roof like that is simply outdated. Nowadays, people use mineral wool or wood fiber insulation. That should keep noise levels down, and the thermal insulation values are only slightly worse, if at all.
@Snowy36 do you have an exposed roof structure, and what type of insulation are you using?
Building a roof like that is simply outdated. Nowadays, people use mineral wool or wood fiber insulation. That should keep noise levels down, and the thermal insulation values are only slightly worse, if at all.
@Snowy36 do you have an exposed roof structure, and what type of insulation are you using?
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pagoni202019 Feb 2021 14:26Yes, I understand that. Of course, there is a horror story for every product, and I also understand that some things are preferred for certain reasons. We are quite familiar with this here, for example, with centralized vs. decentralized mechanical ventilation, heat pump yes/no, vinyl flooring yes/no, etc.
I have read a few things as well, but I also know that the internet tends to highlight the worst isolated cases while the many normal cases are often not mentioned.
However, stone wool or wood fiber insulation have significantly "worse" values, so they cannot be directly replaced one-to-one.
@parcus In your opinion, to what extent does such a roof cause any disadvantages? I once lived under a roof like that and didn’t find it any less comfortable. From what I have found by searching, exterior insulation between rafters still offers the best performance.
I am happy to learn and find out more, but I prefer concrete information.
I have read a few things as well, but I also know that the internet tends to highlight the worst isolated cases while the many normal cases are often not mentioned.
However, stone wool or wood fiber insulation have significantly "worse" values, so they cannot be directly replaced one-to-one.
@parcus In your opinion, to what extent does such a roof cause any disadvantages? I once lived under a roof like that and didn’t find it any less comfortable. From what I have found by searching, exterior insulation between rafters still offers the best performance.
I am happy to learn and find out more, but I prefer concrete information.
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