ᐅ Poroton (36.5 cm) versus expanded clay solid wall (41 cm)

Created on: 21 May 2020 09:17
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Bluesky
Hello dear community,

Although this topic has been discussed in several posts before, long-term experiences are missing here.
I am currently planning a 150 m² (1,615 sq ft) new build with a basement. We have now narrowed down our choice to two builders who differ fundamentally in their building materials.
The house is planned to be built without insulation, using a monolithic construction method. One builder wants to use aerated concrete or Poroton blocks (wall thickness 36.5 cm (14 inches)), while the other plans to use a solid precast wall made of expanded clay aggregate with a wall thickness of 41 cm (16 inches). We are now a bit uncertain because the thermal transmittance (U-value) given by the builders differs greatly: 0.21 W/m²K for Poroton and 2.2 W/m²K for expanded clay. Both assure us that the houses meet the KFW 55 standard.
I am unclear how the U-values can differ so much or whether other factors, such as the mortar used with Poroton, are included. The insulation in the attic and the windows (triple glazed) seem comparable in both cases. Are there any long-term experiences in this forum with solid walls made from expanded clay?
Can you tell me whether a similar energy balance for heating can be expected based on the KFW 55 standard?
Our concern is that with poor insulation and a heat pump, we might not achieve sufficient room heating or end up with very high heating costs due to additional electric heating rods.

Best regards,
Sven
11ant13 Jun 2020 19:54
hauspeter schrieb:

It is possible that windows with poor sound insulation can be a weak point and reduce the overall soundproofing. However, the soundproofing of solid walls is definitely not undone as if the entire house were made of glass.
No, it is even as if it were made of nothing – for that, an unsealed installation gap is enough.
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hauspeter
14 Jun 2020 09:43
11ant schrieb:

No, it’s actually like it’s made from nothing – the unsealed installation gap alone is enough for that.
Then soundproof walls along highways would have to be designed as tunnels with airlocks at the entrances and exits. But they are just walls and open at the top.
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hegi___
14 Jun 2020 12:15
According to a study, the columns should have a sound insulation rating that is 10-15 dB higher to ensure they do not perform worse than the windows.
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Snowy36
14 Jun 2020 12:43
hegi___ schrieb:

According to a study, the columns should have a sound insulation rating that is 10-15 dB higher so that they are not worse than the windows.

Could you please explain that in more detail? I don’t quite understand.
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hegi___
14 Jun 2020 13:03
Google: Soundproofing of joints - ift Rosenheim
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Snowy36
14 Jun 2020 13:29
Of course, if you have a poorly executed joint somewhere, sound will come through there, but you should be able to identify that it is coming through that spot....