Hello everyone,
We are currently planning our single-family home in the Stuttgart area. Apart from the exterior wall, most details are already decided. The house will be built in a quiet residential area with underfloor heating and gas.
I have received three options:
1. 17.5 cm (7 inches) brick + external thermal insulation composite system (ETICS) (standard wall) with no extra cost.
2. Ytong 36.5 cm (14 inches) block – if I may call it that – with a thermal transmittance of 0.23 W/m²K – additional cost: €8,900.
3. Poroton with 0.19 W/m²K – additional cost: €12,200.
I don’t really want to insulate my house with expanded polystyrene (EPS). I’m not a fan of that. Now I’m hesitating between options 2 and 3. What would you recommend?
Thank you very much.
We are currently planning our single-family home in the Stuttgart area. Apart from the exterior wall, most details are already decided. The house will be built in a quiet residential area with underfloor heating and gas.
I have received three options:
1. 17.5 cm (7 inches) brick + external thermal insulation composite system (ETICS) (standard wall) with no extra cost.
2. Ytong 36.5 cm (14 inches) block – if I may call it that – with a thermal transmittance of 0.23 W/m²K – additional cost: €8,900.
3. Poroton with 0.19 W/m²K – additional cost: €12,200.
I don’t really want to insulate my house with expanded polystyrene (EPS). I’m not a fan of that. Now I’m hesitating between options 2 and 3. What would you recommend?
Thank you very much.
B
Bauexperte7 Jan 2015 12:01Hello,
K1300S schrieb:Nope ...
A thermal transmittance value of 0.035 W/m²K or even less can only be achieved with insulation materials like mineral wool, EPS, etc.
Ahem, I even see a minimum value of only 0.07 here. Regarding the U-value, I hope you agree that 0.22 (just taken at random) W/m²K is greater than 0.035, right? If 0.35 (which is an order of magnitude higher) was meant here, I doubt that such a value would allow for a building method compliant with energy-saving regulations. However, I admit that I was somewhat careless and did not consistently distinguish between W/mK (specific thermal conductivity, lambda) and W/m²K (U-value).
In any case, it remains that the construction specification seems more designed to confuse potential buyers with impressive-looking values than to provide reliable information to the interested layperson.
Good luck
K1300S
In any case, it remains that the construction specification seems more designed to confuse potential buyers with impressive-looking values than to provide reliable information to the interested layperson.
Good luck
K1300S
Hello K1300S and Bauexperte,
thank you for your feedback. Of course, the overall concept is important and makes sense. However, as the client, I need to question individual parts of the concept and, as far as possible for a layperson, form a clear understanding.
Basically, I am doing nothing more than spot checks with the goal of questioning and gaining more confidence.
I have now also asked our architect/engineer for clarification. In the construction specification for “delivery and installation of a 42cm (16.5 inches) thick aerated concrete masonry wall PP2 WLG 0.35,” the following block is meant:
H+H Efficiency Block, U-value = 0.18, thermal conductivity (lambda) = 0.08, which would roughly correspond to an energy-efficient house standard 55. What do you think? Sounds good, right?
I also asked if it would be better to use a Poroton T9 block. He said that would certainly be possible and would be roughly the same price in terms of materials. However, different tradespeople (electricians, plumbers, etc.) would prefer not to work with Poroton because it tends to break easily when cutting or chasing. Aside from the fact that the break points (which would be sealed with insulating mortar or similar) could more easily create thermal bridges, tradespeople would also tend to bid higher for their work in tenders compared to the much simpler aerated concrete block (for example, H+H). That sounds plausible at first, but I’m not sure if it really is that way. I trust him though (he is not a developer). Additionally, Poroton is more common in central and southern Germany. In northern Germany, many tradespeople are reluctant to use it and generally don’t actively offer it.
The H+H Efficiency Block is one of the best aerated concrete blocks.
thank you for your feedback. Of course, the overall concept is important and makes sense. However, as the client, I need to question individual parts of the concept and, as far as possible for a layperson, form a clear understanding.
Basically, I am doing nothing more than spot checks with the goal of questioning and gaining more confidence.
I have now also asked our architect/engineer for clarification. In the construction specification for “delivery and installation of a 42cm (16.5 inches) thick aerated concrete masonry wall PP2 WLG 0.35,” the following block is meant:
H+H Efficiency Block, U-value = 0.18, thermal conductivity (lambda) = 0.08, which would roughly correspond to an energy-efficient house standard 55. What do you think? Sounds good, right?
I also asked if it would be better to use a Poroton T9 block. He said that would certainly be possible and would be roughly the same price in terms of materials. However, different tradespeople (electricians, plumbers, etc.) would prefer not to work with Poroton because it tends to break easily when cutting or chasing. Aside from the fact that the break points (which would be sealed with insulating mortar or similar) could more easily create thermal bridges, tradespeople would also tend to bid higher for their work in tenders compared to the much simpler aerated concrete block (for example, H+H). That sounds plausible at first, but I’m not sure if it really is that way. I trust him though (he is not a developer). Additionally, Poroton is more common in central and southern Germany. In northern Germany, many tradespeople are reluctant to use it and generally don’t actively offer it.
The H+H Efficiency Block is one of the best aerated concrete blocks.
There is no such thing as the "best" building block anyway. As linked in Bauexperte’s post, Ytong even offers 0.07, and in Denmark, as low as 0.06. These provide better insulation. However, the overall concept is what really matters. What is the target? Passive House standard like KfW55?
I still don’t understand why WLG 0.35 is used (it simply doesn’t fit), but never mind.
The regional differences in construction methods are true, although I assume that both aerated concrete and perforated bricks can deliver similar results. Whether an electrician checks the masonry in advance, I don’t know. With the right tools, neither material is really a problem. Also, there definitely won’t be thermal bridges at the joints, since the insulation remains in place. Clay hardly provides any insulation anyway.
However, you should keep in mind that not every type of anchor will hold in aerated concrete. For that reason, I chose Poroton at the time and have not regretted it so far.
I still don’t understand why WLG 0.35 is used (it simply doesn’t fit), but never mind.
The regional differences in construction methods are true, although I assume that both aerated concrete and perforated bricks can deliver similar results. Whether an electrician checks the masonry in advance, I don’t know. With the right tools, neither material is really a problem. Also, there definitely won’t be thermal bridges at the joints, since the insulation remains in place. Clay hardly provides any insulation anyway.
However, you should keep in mind that not every type of anchor will hold in aerated concrete. For that reason, I chose Poroton at the time and have not regretted it so far.
Thank you, K1300S. That wasn’t what I meant either. He said, "under the aerated concrete blocks, the H+H efficiency block would be the best." Are there differences between Ytong, Hebel, H+H, etc.?
We do not plan any additional insulation. Only interior and exterior plaster (over reinforcing mesh... or similar).
We do not plan any additional insulation. Only interior and exterior plaster (over reinforcing mesh... or similar).
Counter-question: Are there differences between Audi, BMW, and Mercedes? (Answer: The differences here are likely very minor and probably mostly related to price or delivery costs due to the distance from the factory.) As mentioned, if H+H is currently at 0.08 W/mK (0.46 Btu·ft/hr·ft²·°F) “at the limit,” then that is “the best insulating aerated concrete block from H+H” – however, Ytong can top that with 0.07 W/mK (0.41 Btu·ft/hr·ft²·°F). At least based on the measured values. Whether that is seriously relevant in practice is another question.
Still, the question remains: Do you want or need to meet a specific energy efficiency standard, or should it simply be “reasonable”? At the time, we chose the T7 because there was virtually no difference compared to the T8. But that does not always have to be the case.
Good luck
K1300S
Still, the question remains: Do you want or need to meet a specific energy efficiency standard, or should it simply be “reasonable”? At the time, we chose the T7 because there was virtually no difference compared to the T8. But that does not always have to be the case.
Good luck
K1300S
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