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

RotorMotor schrieb:

Could you please elaborate on that a bit?

It's just plastic! Exterior wall insulation systems (ETICS) use expanded polystyrene with all its advantages and disadvantages. You definitely can't drive a nail into it.

ypg schrieb:

It's just plastic! ETICS is Styrofoam with all its pros and cons.

Maybe a bit more nuanced. ETICS can be "plastic" like EPS/PUR/XPS, but also made from phenolic resin, hemp, wood fiber, or even mineral wool or mineral foam. Then you would have an ETICS together with masonry that is fully mineral-based, similar to monolithic construction.

Franke86 schrieb:

Since I want to go for KfW 40 (Plus), he told me that I would need 24 hollow bricks plus 18 cm (7 inches) of external thermal insulation composite system (ETICS)! (Additional cost here: 1800 €).
What would you recommend? Is ETICS still considered "modern," or is it no longer common? [...]
Since I also wanted to know prices for purely monolithic construction, I was given the following offer (standard is 24 hollow bricks plus 14 cm (5.5 inches) ETICS):

Putting aside my views* on ETICS and on KfW4711turbo, from my perspective there is essentially only one fundamental decision for you:
A. You asked for alternatives just because of the extra cost, or
B. You have some reservations or other objections against ETICS (bearing in mind that the KfW standard not only affects the wall construction but may also be linked to controlled mechanical ventilation, where I will also leave my views* aside). This A/B answer can only be found by yourself.
When deciding on wall construction, also consider my "brick mantra" (there is no one-size-fits-all solution, but there is a wall construction with which the installer has the most experience, and all others carry greater potential for complications).
If ETICS is basically acceptable to you, then adding 4 cm (1.5 inches) more insulation thickness mainly affects the U-value and not your practical experience, and secondly you stay with basically the same wall setup (so you do not stray from the installer’s standard routine).
In my opinion, you should only change the masonry unit of the structural shell if the builder has roughly the same level of experience with it (for example, if they build 60:40 with bricks X/Y, but not 90:10). Using the "same" brick, filled versus unfilled, is basically unchanged in that sense, but I agree with the experts who advise against doubling up on internal filling and external insulation, as I consider this a well-intentioned but nearly naive mistake.

*) Please use the search function; my thread history is full of this, and a large part of the two topics ETICS and controlled mechanical ventilation turns out to be subjective on closer inspection

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ypg schrieb:

It's just plastic!
ETICS (External Thermal Insulation Composite System) uses expanded polystyrene with all its advantages and disadvantages. You can't drive a nail into it.

How many nails have you actually hammered into your facade...?

We have 20cm (8 inches) ETICS here. As long as no Slovak baker slaps anything onto the exterior wall, it is absolutely uncritical regarding durability and appearance when installed correctly, and the pictures are hung on the inside 😉

With ETICS, you have a well-insulated outer layer with state-of-the-art U-values.

halmi schrieb:

With ETICS, you get a highly insulated exterior shell with state-of-the-art U-values.

Although you can also achieve this monolithically. Personally, I find that concept much more appealing. The fact that you can easily mount a mailbox and an outdoor light anywhere is an added bonus.

ETICS with expanded polystyrene (EPS) is obviously the cheapest option, but then you do have polystyrene on your walls. I consider that absolutely outdated. The alternatives listed by @nordanney are somewhat more expensive than EPS.

What’s so bad about the styrofoam? The external thermal insulation composite system (ETICS) can still be thermally recycled even after 50 years of protecting the climate through its insulation performance. That’s a great environmental balance. It’s actually those YTONG houses with gas condensing boilers that are the bigger climate offenders and worth a local climate strike.