Wall construction: 15 cm calcium silicate brick plus 25 cm external thermal insulation composite system (ETICS)

Hello everyone,

our detached single-family house Kfw 40 + (9 x 16m, 2 floors with basement) is being built from sand-lime brick.
Interior walls 11cm or 15cm, exterior walls 15cm plus 25cm ETICS.
The 15cm exterior wall seems very thin to me, especially when I think of the large rooms.
Of course, everything is statically calculated and designed. Nevertheless, I would feel more comfortable with a 17.5cm wall.

Are my concerns justified or unfounded?

Thank you very much

There is nothing more stable than sand-lime brick available. And structural engineering always includes a large safety margin. So the concerns themselves are unfounded. But if you feel more comfortable with 17.5 cm and the additional cost is affordable, why not?

KfW 40 in a solid house is economically nonsense anyway just for a good feeling. If you then also build a bit more stone inside, you have more mass to buffer the heat in summer. So go ahead.

I built with 17.5 Kalksandstein + 20cm WDVS and can confirm that the sound insulation of this wall construction is very good according to my subjective experience. And yes, even the 17.5 walls do not appear particularly massive visually in the shell construction - but the high bulk density of the stones is pleasantly noticeable when carrying them :-)

Better have the requirement of 24cm insulation - even for [KfW 40] - checked. Sounds like a waste.

We have 24cm KS and 16cm 032 WDVS on it. But it is only according to the Energy Saving Ordinance. The bricks are really heavy. I was surprised. :)

We have 24cm KS

If Putin attacks you don't even have to go to the basement... Just a little away from the window ;)