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
Both are absolutely rubbish. Don’t just focus on thermal insulation but also consider soundproofing. These energy-saving regulation houses are unfortunately just cardboard-box constructions.
Use a 36.5 cm (14 inch) filled Poroton brick. That way, you’ll have something solid and won’t regret it.
Use a 36.5 cm (14 inch) filled Poroton brick. That way, you’ll have something solid and won’t regret it.
E
Elithenas21 May 2020 13:04Bookstar schrieb:
Both are absolute rubbish. Don’t just look at thermal insulation but also soundproofing. These energy-saving regulation houses are unfortunately just flimsy cardboard constructions.
Use a 36.5 cm (14.4 inches) filled Poroton brick. Then you have something solid and won’t regret it. What kind of vague and undifferentiated statement is that?
What exactly makes a lightweight expanded clay aggregate (Liapor, Klimapor, etc.) wall a "flimsy cardboard" construction?
HFP Liapor walls regularly meet the requirements of DIN 4219 – especially due to the absorption effect of lightweight expanded clay surfaces.
The same applies to lightweight expanded clay walls as precast elements or, for example, made from acoustic concrete blocks – which also easily comply with the ÖNORM B 8115 standard.
Lightweight expanded clay aggregate in itself provides good sound insulation.
E
Elithenas22 May 2020 09:15I am currently building with expanded clay aggregate (Klimapor, company Lechner Massivhaus, 49 cm (19 inches) wall thickness) and, so far, I am very satisfied with the material and the system.
The shell construction was completed in 5 days – with “shell construction” meaning the traditional sense here; it is far from a fully enclosed building envelope as you would have in timber frame construction.
The workmanship is very precise – both from the factory and during assembly.
We are building in a Bauhaus style and have two terraces on the upper floor, projections, cantilevered elements, etc. – so naturally, there are areas where additional insulation is applied to avoid thermal bridging.
However, across the large surfaces, the house does not require an external thermal insulation composite system (ETICS) / external wall insulation.
In my view, this is a definite advantage.
In addition to the specific positive properties of expanded clay aggregate.
We do not have a KfW certification – but that is due to our (active) climate control via multi-split units.
The heating load calculation for our building, with an effective heated area of 200 m² (2,150 sq ft), is 4.8 kW.
The shell construction was completed in 5 days – with “shell construction” meaning the traditional sense here; it is far from a fully enclosed building envelope as you would have in timber frame construction.
The workmanship is very precise – both from the factory and during assembly.
We are building in a Bauhaus style and have two terraces on the upper floor, projections, cantilevered elements, etc. – so naturally, there are areas where additional insulation is applied to avoid thermal bridging.
However, across the large surfaces, the house does not require an external thermal insulation composite system (ETICS) / external wall insulation.
In my view, this is a definite advantage.
In addition to the specific positive properties of expanded clay aggregate.
We do not have a KfW certification – but that is due to our (active) climate control via multi-split units.
The heating load calculation for our building, with an effective heated area of 200 m² (2,150 sq ft), is 4.8 kW.
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