Hello,
As mentioned in the title, we are building with Ytong to achieve KfW55 standard.
Now our construction company has offered to build with 36.5 cm (14 inches) Ytong blocks instead of 24 cm (9.5 inches) Ytong plus 12 cm (5 inches) of full thermal insulation.
Advantages according to the construction company:
1. All values for KfW55 are met just the same.
2. Fastenings on the exterior wall, e.g. satellite dish, awning, etc., would be much easier to install because it’s solid masonry directly, without soft insulation.
3. Our site manager considers the insulation a sort of "hazardous waste" from his point of view, as its production and disposal are quite energy-intensive...
Disadvantages: none?? Price-wise it would make no difference for us.
What do you think?
Especially point 2 appeals to me...
Point 3 is just a personal opinion and therefore secondary for now.
Thanks and best regards to everyone!
As mentioned in the title, we are building with Ytong to achieve KfW55 standard.
Now our construction company has offered to build with 36.5 cm (14 inches) Ytong blocks instead of 24 cm (9.5 inches) Ytong plus 12 cm (5 inches) of full thermal insulation.
Advantages according to the construction company:
1. All values for KfW55 are met just the same.
2. Fastenings on the exterior wall, e.g. satellite dish, awning, etc., would be much easier to install because it’s solid masonry directly, without soft insulation.
3. Our site manager considers the insulation a sort of "hazardous waste" from his point of view, as its production and disposal are quite energy-intensive...
Disadvantages: none?? Price-wise it would make no difference for us.
What do you think?
Especially point 2 appeals to me...
Point 3 is just a personal opinion and therefore secondary for now.
Thanks and best regards to everyone!
B
Bieber08151 Mar 2017 08:47astron schrieb:
Now our construction company has offered to build with 36.5cm (14 inches) Ytong blocks instead of 24cm (9.5 inches) Ytong plus 12cm (5 inches) full thermal insulation. Where did the original idea of 24cm (9.5 inches) Ytong plus insulation come from? Who chose this and why?
I would tend to go for a monolithic approach here (meaning 35.5cm (14 inches) Ytong) if that is already sufficient for KfW55. But don’t just compare the final result—also look at the actual transmission heat losses where available. There should be calculations if KfW55 is to be achieved.
Culture clash – good point!
This is something known from nutritional “science,” where the trend of who or what is the villain keeps changing. Today, expanded polystyrene (EPS) insulation is praised, but tomorrow it’s the “bad cholesterol.” Then the houses are left cold in their 175mm (7 inches) summer outfits with torn-off polystyrene, while the bricklayers celebrate golden times. I better start reshuffling my investment portfolio.
https://www.instagram.com/11antgmxde/
https://www.linkedin.com/company/bauen-jetzt/
This is something known from nutritional “science,” where the trend of who or what is the villain keeps changing. Today, expanded polystyrene (EPS) insulation is praised, but tomorrow it’s the “bad cholesterol.” Then the houses are left cold in their 175mm (7 inches) summer outfits with torn-off polystyrene, while the bricklayers celebrate golden times. I better start reshuffling my investment portfolio.
https://www.instagram.com/11antgmxde/
https://www.linkedin.com/company/bauen-jetzt/
I checked the U-value calculator again. Pure Ytong 365mm (14 inches) in PP2-0.35 results in a U-value of 0.235 W/m²K. The reference value method for KfW 55 won’t work with this, but it is still definitely feasible.
The original wall structure using the same Ytong but only 140mm (5.5 inches) thick plus 120mm (5 inches) of EPS 035 achieves a U-value of 0.159 W/m²K, which comes close to KfW 40.
As a result, the initially proposed setup will have slightly lower heating costs. The heating load is lower, so it might be possible to switch to a smaller heat generator and save money. The better wall construction also means other components require less effort to meet the KfW requirements, especially the windows, which could be cheaper. However, this doesn’t help you because the project will be built as a turnkey contract (GU), though this could explain why the builder initially wanted to use that method.
The original wall structure using the same Ytong but only 140mm (5.5 inches) thick plus 120mm (5 inches) of EPS 035 achieves a U-value of 0.159 W/m²K, which comes close to KfW 40.
As a result, the initially proposed setup will have slightly lower heating costs. The heating load is lower, so it might be possible to switch to a smaller heat generator and save money. The better wall construction also means other components require less effort to meet the KfW requirements, especially the windows, which could be cheaper. However, this doesn’t help you because the project will be built as a turnkey contract (GU), though this could explain why the builder initially wanted to use that method.
K
Knallkörper1 Mar 2017 16:28I also believe that the monolithic construction is better, especially in terms of durability.
11ant schrieb:
Glaubenskrieg - gutes Stichwort !That's it. For me, Ytong is the worst... poor sound insulation and issues with thermal bridges, leading to significantly more facade damage. On top of that, unnecessarily thick walls despite proper thermal insulation.
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