ᐅ Exterior Wall for KfW 40 (+) Standard: With or Without External Thermal Insulation Composite System (ETICS)?

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):

• 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

Franke86 schrieb:

What would you recommend to me? Is ETICS still considered "up-to-date," or is it no longer used?

It is just as up-to-date as monolithic construction. Cheaper than monolithic, but criticized by many as a "plastic shell."

Is that good or bad now XD

Keep an eye on the sound insulation values of the T9 brick. It’s better to request quotes for a filled brick (perlite or mineral wool). The additional costs will be higher, though.

If the "plastic" in the external thermal insulation composite system (ETICS) bothers you, you can also ask for mineral wool as insulation material for the ETICS.

Franke86 schrieb:

Is this good or bad now XD

Rather bad. I wouldn’t build with ETICS again.
What puzzles me is: is the 18cm (7 inches) insulation enough for your KfW40 standard?

ypg schrieb:

I wouldn’t choose to build with ETICS again.

Could you explain your reasons a bit more?