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
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Snowy36
22 Sep 2020 14:20
Well, information is being requested... The answer was: use filled insulation... if you don’t listen: that’s how it is
Just like that
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Ybias78
22 Sep 2020 17:27
Snowy36 schrieb:

Well, information was requested ... the answer was: take filled ... if you don’t listen: that’s how it is
Just like that

And why filled? I visited the general contractor today. He said if you live near a railway, the next best option in terms of sound insulation costs an additional €6,000 and is more than enough.
Nida35a22 Sep 2020 17:41
Village, roosters crowing, church bells, neighbor’s circular saw, that’s what you want, that’s something Berlin couldn’t offer you
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Ybias78
22 Sep 2020 17:47
Nida35a schrieb:

Village, roosters crowing, church bells, neighbor’s circular saw,
that’s what you want, Berlin couldn’t offer you that

Exactly, and birdsong in the morning. I think sound is also very subjective. Some “retirees” are bothered by children laughing, while others find the noise from playing children less disturbing.
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Snowy36
22 Sep 2020 21:11
I would never build without insulation again, and unlike your situation, we don’t live on a village street. As my predecessor already mentioned: if someone is talking or shouting outside, you can hear it inside, along with lawn mowers and so on. If you enjoy those kinds of noises from 6 a.m. until 10 p.m., go ahead. For everyone else, I strongly recommend the 6K system. Feel free to compare the sound insulation values and then look up what a 5 dB difference actually feels like. I have never met anyone who thought their house was too quiet.
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Ybias78
22 Sep 2020 21:29
Snowy36 schrieb:

I would never build unfilled again, and where we live, there’s no village street like you have... as my predecessor already mentioned: if someone is talking or shouting outside, you can hear it inside, lawnmowers, etc. If you enjoy such noises from 6 a.m. until 10 p.m., go ahead... I recommend the 6K to everyone else. You’re welcome to compare the sound insulation values and then look up what a 5 dB difference actually feels like... I’ve never met anyone who thought their house was too quiet...

Who would be shouting around here? We live in a village. You rarely meet anyone. The plot is almost 1,500 m² (16,000 sq ft) in size, and the house will be built about 15 m (50 feet) from the property boundary.