ᐅ Sand-lime brick with external thermal insulation composite system (ETICS), aerated autoclaved concrete (AAC) blocks, or double-layered sand-lime brick construction

Dear users,

I hope you can help us.
We want to build a rural house in Bavaria.
2 full floors + attic.
11 x 11.8 m (36 x 39 feet) floor area.
38° pitched roof.
2 residential units (possibly later).
A passive house standard is aimed for, according to the energy consultant.
Since our site manager retired, we need to find another company.
All timber houses have become more expensive; offers for the shell construction are mostly between about 287,000 and 350,000.
Now we have an offer from Ytong for 150,000, but Ytong causes us some concerns regarding sound insulation (2 loud children, etc.) and the fact that moisture is only released slowly, as well as difficulties with mounting fixtures.

We have now often heard that in our case, 24 cm (9.5 inches) calcium silicate blocks plus an external thermal insulation composite system (ETICS) would be cheaper than Ytong.
Do you possibly have some experience with this?
Or also calcium silicate block square meter prices including insulation, since the facade cost is missing from the Ytong offer.

Thank you very much.

In general, aerated concrete seems to be a relatively affordable construction method, which doesn’t necessarily have negative implications. From my experience, it is rarely possible to predict which building material a contractor can offer at a lower price, as this varies greatly depending on the region. Where I come from, solid sand-lime bricks are the standard material, traditionally with a two-layer brick veneer, and nowadays often with external thermal insulation composite systems (ETICS) plus render. If you want hollow clay blocks there, for example, this usually comes with a price premium, and the same might apply to aerated concrete. Where I currently live, aerated concrete appears to be more common and therefore generally cheaper. However, it still depends on the individual builder, so advice from another part of the country is hardly helpful. That’s why:

Ask your preferred builders what they charge for the specific construction method you want, then you will know. Otherwise, it’s just guessing, which won’t help you at all.

PS: A rough construction cost of 150,000 EUR for a building of this size sounds quite affordable to me.

As mentioned, this depends heavily on the region. Here, aerated concrete is also the cheapest, followed by calcium silicate bricks plus external thermal insulation composite system (ETICS), with cavity wall construction naturally being the most expensive. Use what your contractor is familiar with and has experience with. When installed correctly, all options are good, unless you have very specific requirements. For example, if your building is directly adjacent to a major road, aerated concrete is not a suitable choice in terms of sound insulation.

Okay, then I guess I’ll have to be patient until the appointment.
We have a sand-lime brick factory about 18km (11 miles) from here, and 20km (12 miles) away there is a construction company that builds most of the sand-lime brick houses in this area.

The other one is a Ytong partner (who also works with sand-lime bricks, mostly for commercial projects) and he said it would cost an additional 20,000€.

I have often read that sand-lime brick would still be cheaper despite external thermal insulation composite systems (ETICS).
The price per square meter for Ytong here is 125€ + 44€ for the masonry work, with a 42.5cm (17 inches) block thickness.
So, about 294€/m³ (cubic meter).

Well, the Ytong contractor says that 24cm (9.5 inches) Ytong on the interior is sufficient to prevent hearing everything from the next room.

We are about 70 meters (230 feet) away from a railway line.
And we also have two noisy children.

Here, you see the brick in about 95% of the houses. When you ask why, the usual answer is “that’s just how it’s always been done” or “everyone else does it that way.”

It is important not to force a masonry worker to use a type of stone they are not familiar with. Always hire someone who has experience with the specific stone you want.

hanse987 schrieb:

It is important not to force a builder to work with a type of stone they are not familiar with. Always choose someone experienced with the specific stone you want.

That’s why we have the other appointment, since this builder only constructs houses with sand-lime bricks (according to the sand-lime brick factory and construction companies, the majority in the district).