ᐅ Masonry using Ytong blocks, 24 cm or 30 cm thick, for a single-family house?
Created on: 20 Aug 2019 20:45
R
Ruska
Hello building experts,
It looks like construction can start soon. I was convinced by the regional TuC partner regarding the overall concept because of the monolithic construction method.
In the "basic package," the masonry is made from 24cm (9.5 inches) Ytong blocks. Does anyone have practical experience with thermal and sound insulation? The residential location is very quiet, traffic-calmed, and has almost no through traffic.
Alternatively, I am considering a build with 30cm (12 inches) blocks; I still need to find out the additional cost.
Best regards,
Ruska
It looks like construction can start soon. I was convinced by the regional TuC partner regarding the overall concept because of the monolithic construction method.
In the "basic package," the masonry is made from 24cm (9.5 inches) Ytong blocks. Does anyone have practical experience with thermal and sound insulation? The residential location is very quiet, traffic-calmed, and has almost no through traffic.
Alternatively, I am considering a build with 30cm (12 inches) blocks; I still need to find out the additional cost.
Best regards,
Ruska
Ruska schrieb:
Is that a typo, or do you actually mean 42.5?
I wouldn’t have expected any compromises on sound insulation here. No, we have a 42.5 cm (17 inches) exterior wall (lambda 0.08) with a U-value of 0.18 W/m²K. We are very satisfied. Soundproofing could be better, but we live on a low-traffic residential street, so it’s not much of an issue.
Regards
Stubai83 schrieb:
No, we have 42.5cm (17 inches) exterior walls (lambda 0.08) with a U-value of 0.18 W/m²K. We are very satisfied. Sound insulation could be better, but we live on a quiet residential street, so there isn’t much noise.
Best regards We built with 0.07 lambda Ytong blocks in the mentioned town and countryside area, with 36.5cm (14 inches) thickness. U-value is 0.21.
Sound insulation is important mainly for the garden due to the decentralized ventilation openings in the walls. Well, it’s really not that noisy here, it could be much worse.
With a child, the noise sources are mostly inside now, haha.
We don’t have any damp walls either. KFW55 standard, by the way. Back then we used gas/solar hot water – nowadays there is a 4-split air-to-air heat pump system added. Perfect for temperatures around 0-10°C (32-50°F) like now. Of course, also in summer. Ytong has very little heat or cold storage capacity, and the screed is decoupled because of the underfloor heating. Working from home, it can easily get up to 26°C (79°F) or more by midday.
For air-source heat pumps, the wall U-value should not exceed 0.20 W/m²K (0.035 BTU/h·ft²·°F). This recommendation is not without reason in the BEG (Building Energy Act), and the building energy regulations will likely be adjusted accordingly as Germany increasingly promotes heat pumps in residential construction. The SCOP values and the crucial annual performance factors are simply too low given the rising electricity costs.
The disadvantage of aerated concrete is its limited suitability for building component activation as a buffer and storage mass. In this respect, any calcium silicate brick with 17.5 plus external thermal insulation composite systems (ETICS) cannot be beaten.
In Germany, cooling loads are becoming increasingly important compared to heating loads. Simply enter your location on the Federal Heat Pump Association’s website and check how many hours per year correspond to which temperatures.
The disadvantage of aerated concrete is its limited suitability for building component activation as a buffer and storage mass. In this respect, any calcium silicate brick with 17.5 plus external thermal insulation composite systems (ETICS) cannot be beaten.
In Germany, cooling loads are becoming increasingly important compared to heating loads. Simply enter your location on the Federal Heat Pump Association’s website and check how many hours per year correspond to which temperatures.
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xMisterDx11 Jan 2023 22:37Phew. When I look at all the things that can go wrong with ETICS (external thermal insulation composite systems), there are some great YouTube series by experts. In comparison, I’m quite happy with a 36.5 cm (14.4 inch) aerated concrete wall, even though it only achieves a U-value of 0.23.
This focus on U-values for masonry is really a bit of an overkill, beyond a certain point. Windows, which make up about one-fifth of the facade area, lose more heat than masonry with a 0.23 U-value.
That means a 10% improvement in U-value does not equate to a 10% energy saving, but maybe only 5%. And that’s without considering the slab and the roof, where significant energy loss occurs as well.
So the claim that a wall needs a U-value of 0.2 or less for a heat pump is nonsense. The entire thermal envelope has to be taken into account.
By the way, for those who complain about the load-bearing capacity of aerated concrete, good luck when you want to install an awning or a somewhat heavy light fixture on your ETICS facade someday. Then you can debate load capacities. But not with aerated concrete walls.
You simply insert wall anchors, and that’s it.
As if that Poroton stuff with its countless tiny air chambers supports loads any better. One hammer drill hit, and inside the block is just rubble. And then what? Gluing? Wall anchors? Where is that supposed to hold? In brick dust?
This focus on U-values for masonry is really a bit of an overkill, beyond a certain point. Windows, which make up about one-fifth of the facade area, lose more heat than masonry with a 0.23 U-value.
That means a 10% improvement in U-value does not equate to a 10% energy saving, but maybe only 5%. And that’s without considering the slab and the roof, where significant energy loss occurs as well.
So the claim that a wall needs a U-value of 0.2 or less for a heat pump is nonsense. The entire thermal envelope has to be taken into account.
By the way, for those who complain about the load-bearing capacity of aerated concrete, good luck when you want to install an awning or a somewhat heavy light fixture on your ETICS facade someday. Then you can debate load capacities. But not with aerated concrete walls.
You simply insert wall anchors, and that’s it.
As if that Poroton stuff with its countless tiny air chambers supports loads any better. One hammer drill hit, and inside the block is just rubble. And then what? Gluing? Wall anchors? Where is that supposed to hold? In brick dust?
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