ᐅ Is a 30 cm aerated concrete (e.g., autoclaved aerated concrete) wall sufficient?

Hello everyone,

We were offered a new solid construction house with aerated concrete system wall elements 30.0 cm (12 inches) thick, lambda 0.09.

(Thermal conductivity 0.09 W/m K, U-value 0.35)

In your opinion, is this still up to date or no longer state of the art?

It is at the level of good houses from 10 years ago. BUT: It meets the requirements according to the Building Energy Act.

It wouldn’t be my choice nowadays. Look on the bright side: Nobody can sell you a construction with even worse build quality ;-)

Is the price a bargain?

sarajevo83 schrieb:
We were offered a solid construction new build with aerated concrete wall elements, 30.0 cm (12 inches) thick, thermal conductivity (lambda) 0.09.
[...] Is this still up to date for you, or no longer state of the art?

nordanney schrieb:
This is on the level of good houses from about 10 years ago. BUT: It meets the requirements according to the building energy law.

At Massivhaus Mittelrhein, they have now switched to Caliber 425, but they were already using Caliber 365 for EH55 under the 2014 Energy Saving Ordinance. I think Caliber 365 monolithic is the best choice, mostly using aerated concrete on the inside as well. Aerated concrete at Caliber 300 sounds like Town & Country (?).

By the way, I still don’t like scattering the same project across multiple single-question threads.

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11ant schrieb:
Aerated concrete in caliber 300 sounds like Town & Country (?)

Oh, no, "system wall elements" probably mean Xella kit houses (?)

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11ant schrieb:
Oh, no, “system wall elements” probably refer more to Xella prefabricated houses (?)

No, I just came across this by chance:
There even with a 36cm (14 inch) wall as a SWE

11ant schrieb:
By the way, I still don’t like spreading the same project across multiple small threads.

Sorry! I thought it would be clearer for all future home builders that way...

sarajevo83 schrieb:
No, I happened to come across this:
There, even with 36cm (14 inches) walls as aerated concrete blocks

Not as "system wall elements," but as plan blocks for self-building. For a price of 145k, this practically means that a total of 326k (471k minus 145k), including the "margin" for your own work, is budgeted to turn the house into a move-in ready home with the help of finishing contractors.

Only the gods know why Xella doesn’t offer the same models as Xella yellow (Ytong) and Xella orange (Hebel), but rather in the quite different versions "STV 157" (Ytong) and "Single-family home city villa 149" (Hebel). Both are kit houses, whereby the Hebel houses are assembled from full-story vertical elements (which requires a crane), while the Ytong houses are built classic brick-by-brick (using the same type of plan blocks from the pallet that you can also buy “individually” at building supply stores, meaning by the pallet but not included in a complete kit with the other parts). In this building materials sales channel, the blocks differ only by the color of the packaging around the pallets. Many value-added resellers (main contractors) also offer the blocks of both brands at various processing levels (up to a move-in ready house). While the kits for both Xella aerated concrete brands also provide for ceilings and even pitched roofs made of aerated concrete, general contractors who work with these plan blocks typically prefer traditional reinforced concrete ceilings and timber roof trusses. I can gladly refer you to someone, but I recommend personal consultation. As I said, we can also meet in MüKä.

sarajevo83 schrieb:
Sorry! I thought this would make things clearer for all future home builders...

No, there are two clear and organized ways both for passive readers and active helpers:
A) Someone has a specific building project (which applies to you), then the clearer way is to discuss the entire project in one thread (like your main thread https://www.hausbau-forum.de/threads/stadtvilla-und-doppelgarage-anordnungsideen.y2p3j1/); or
B) Someone has no specific project, then it makes the most sense to join the closest existing "which block is the wisest choice" thread.

Unfortunately, option C is the most popular: everyone who is clueless (and anyone who is not or doesn’t want to be clueless should avoid this) starts their own "Newbies just cross the street without looking left or right" thread with the eternal FAQ about whether to choose the favorite block of the regular group or the other one. Where I always have to say that while the red brick builders and the white brick builders argue, clever Piggy just laughs as the winner and simply uses pumice. This was already done here when the Rhine still separated the French from the Romans ;-)
The clueless version is only authentic if you open a fresh bag for every little single aspect. :-)

And the escalation of that is the premium clueless version, as a password forgetter every half year (from the first building wish up to the landscaping, easily half a dozen times) showing up here with a new name each time. Fortunately, that only happens as rarely as there are Alpha K-Wins.

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