ᐅ Insulation for KfW 70 Standard – a quick question

The developer states this in their building specification:
17.5cm (7 inches) sand-lime brick with approximately 12-16cm (5-6 inches) external thermal insulation composite system (ETICS) with a thermal conductivity of 0.035 W/(m·K).
Is this sufficient, or is it simply the most cost-effective solution?

Hello,

SimonMoers schrieb:
The developer writes this in their building specification,
17.5 cm (7 inches) calcium silicate bricks with approx. 12-16 cm (5-6 inches) external thermal insulation composite system (ETICS, thermal conductivity 0.035)
Is this sufficient, or is it simply the cheapest solution?

You need to free yourself from the idea that someone in this forum can answer this question definitively. You will only know if it is appropriate once the KfW certification is obtained, assuming you want to build to KfW 70 standard. If not, expect additional costs since this deviates from the building specifications.

As a rule, however, 17.5 cm (7 inches) plus 16 cm (6 inches) ETICS should be sufficient; although I personally would never build it that way 😉

Best regards, Bauexperte

Thanks for the information. I have no knowledge of construction and am currently trying to educate myself. However, based on my initial research, it’s not as simple as I thought. Great if that is enough!

What would you choose? According to the building specifications, I only have the option between calcium silicate blocks and perforated clay bricks, at least as far as I can tell. 🙄

SimonMoers schrieb:

But from my initial research, it’s not as simple as I thought.

It would be strange if it were that simple; then no one would need to learn a trade anymore 😉

SimonMoers schrieb:

What would you choose? According to the building specification, my options are only calcium silicate blocks or perforated bricks.

Me? I build exclusively monolithically 😀

However, if your preferred method is specified like that in the building specification, you will hardly be able to avoid an external thermal insulation composite system (ETICS); especially if you want to buy the house and land as a package.

Regards, Bauexperte

Sand-lime brick plus ETICS (External Thermal Insulation Composite System) is probably not the most cost-effective solution. In my personal opinion, however, it is the best. Good sound insulation, good heat protection (both naturally depending on the thermal resistance value, R-value), and solid walls. The 17.5 + 16 cm (7 + 6 inches) thicknesses are, of course, at the lower end.

maximax schrieb:

The 17.5 + 16 are obviously on the lower end.

Why? Should the original poster rather have castle walls built?

Regards, Bauexperte