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
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
I believe that everything needs to fit together properly... we have a roof with 45 dB, walls with 40 dB, and windows with 32 dB... that was nonsense because with 32 dB, despite living in a quiet new development, you can clearly hear children and other noises.
We replaced one window with a 40 dB rated one—what a huge difference.
I think relying on architects, developers, or general contractors is a mistake... otherwise, we wouldn’t have a controlled residential ventilation system (which we never really use) and PUR insulation in the roof (we’re not near an airport, after all). We would just be frustrated to no end. General contractors almost always prefer to use hollow bricks because a lot falls out of the alternatives.
It doesn’t help me at all that they always build with hollow bricks... you have to inform yourself, and everything should match well together.
I also don’t think asking neighbors is appropriate—who admits that what they chose wasn’t really the best? Very few.
Besides, nobody really has any serious problems with their house... and then the neighbor empties the dehumidifier outside again.
We replaced one window with a 40 dB rated one—what a huge difference.
I think relying on architects, developers, or general contractors is a mistake... otherwise, we wouldn’t have a controlled residential ventilation system (which we never really use) and PUR insulation in the roof (we’re not near an airport, after all). We would just be frustrated to no end. General contractors almost always prefer to use hollow bricks because a lot falls out of the alternatives.
It doesn’t help me at all that they always build with hollow bricks... you have to inform yourself, and everything should match well together.
I also don’t think asking neighbors is appropriate—who admits that what they chose wasn’t really the best? Very few.
Besides, nobody really has any serious problems with their house... and then the neighbor empties the dehumidifier outside again.
Teemoe86 schrieb:
The fact is that aerated concrete on its own provides worse sound insulation than other construction methods.The fact is that decades of experience from multiple buildings count less than what you find on the internet, where a chart says block X is good and block Y is bad. I’m happy to be called stubborn when I think for myself.https://www.instagram.com/11antgmxde/
https://www.linkedin.com/company/bauen-jetzt/
H
hauspeter16 Jun 2020 09:08Teemoe86 schrieb:
However, the developer uses standard 30cm (12 inch) Ytong blocks, as I read. Ytong downside: poor sound insulation.For this reason, we chose a developer who offers cavity walls with Poroton blocks. Ytong has good thermal insulation properties and is easy to work with. But that’s where the advantages end.
@hauspeter
We initially decided on lightweight expanded clay aggregate (LECA) as well, and after visiting the manufacturer's site, we chose a construction company from their list of references. This company exclusively builds with LECA, and everything went smoothly. The shell is standing (without any cracks), without mechanical ventilation.
Regards, Nida35a
We initially decided on lightweight expanded clay aggregate (LECA) as well, and after visiting the manufacturer's site, we chose a construction company from their list of references. This company exclusively builds with LECA, and everything went smoothly. The shell is standing (without any cracks), without mechanical ventilation.
Regards, Nida35a
Expanded clay aggregate is a very interesting building material. I looked into it as well and visited Lechner Massivhaus on site (called KlimaPOR there). In many aspects, expanded clay aggregate has good properties, for example, sound insulation. One downside is that you have to combine it with EPS (expanded polystyrene) insulation to meet a KfW55 or even KfW40 standard (if that is the goal). Otherwise, you would have to build the wall very thick. This was the statement from the sales advisor.
If achieving KfW55 or higher is a goal, a Poroton block (filled or unfilled) is probably the better choice.
If achieving KfW55 or higher is a goal, a Poroton block (filled or unfilled) is probably the better choice.
I live in a pumice stone region, where Bisotherm is also very popular (monolithic construction as far as I know, without excessive wall thickness).
https://www.instagram.com/11antgmxde/
https://www.linkedin.com/company/bauen-jetzt/
https://www.instagram.com/11antgmxde/
https://www.linkedin.com/company/bauen-jetzt/
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