New single-family house (KFW70)/aerated concrete vs. sand-lime brick/what to use?

Hi everyone,

we want to build with a general contractor and have obtained corresponding offers. Some build with aerated concrete, others with sand-lime brick. Others use aerated concrete for the exterior masonry and install sand-lime brick inside.

What would you favor from your point of view? Is this mixture of aerated concrete outside and sand-lime brick inside common and preferable?
Do you have to worry about cracks since both stones have different expansion? Or is this not an issue with professional construction?

What would you currently use (have installed) yourselves, that is, what would be your preferred building material?

Thanks in advance,
Lacos

Do you have to worry about cracks because both stones have different expansion? Or is this not an issue with proper construction?

Yes, it is actually a big issue... I would not want to mix the building materials... even though many say that it all works fine... you'll have the trouble afterwards...

The wall construction is a matter of philosophy...

Are you concerned about: sound insulation, indoor climate, thermal insulation, fastening options, costs, environmental protection?

The wall construction is a matter of philosophy...

Are you concerned with: noise protection, indoor climate, thermal insulation, fastening options, costs, environmental protection?

Noise protection is secondary, since it is a single-family house. Rather thermal insulation and fastening.

Hello,

What would you favor from your perspective? Is this mix of aerated concrete on the outside and sand-lime brick on the inside common and preferable? Do you have to worry about cracks because both stones have different expansion rates? Or is this not an issue with proper construction?

Quite a few builders use sand-lime brick for the interior walls because this stone offers better sound insulation; especially in the attic, where the bedrooms are located, this is a popular argument. This way, they avoid later disputes with sensitive homeowners.

I generally advise against mixed masonry. Whether you build with aerated concrete or hollow bricks is actually a gut decision. Those who need the red brick for their gut usually choose Poroton. Those who prefer to avoid rapid cement use choose aerated concrete; special anchors are needed for almost every stone. We solve the question of sound insulation with significantly thinner interior walls (with 36.5 cm exterior masonry, sound insulation is no longer an issue) by constructing the attic walls either in lightweight construction or on the upper floor – that is, a two-story building – with gypsum boards. Both are uncritical compared to hollow bricks or aerated concrete but, inexplicably, have a bad reputation among potential homeowners. I attribute this to the fact that they unfilteredly adopt statements from the internet without being familiar with the subject.

Rhenish regards

With us, gypsum boards are also the favorite for the interior walls on the upper floor. We also have this material in our current apartment for a few interior walls (10 cm thick). The sound insulation is impeccable and it is also stable (above me hangs a wall-mounted shelf full of heavy folders while I am writing this here )

Drilling is very easy, regular plugs are sufficient, and you can also easily get a nail into the wall.

Hello,

...What would you favor from your perspective? ...

Monolithic AW rarely sufficiently meet all competing demands equally. They are always a compromise, but cheap!

regards