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
According to websites, a 30 cm (12 inch) Ytong wall plus plaster provides around 46 dB of sound insulation, while a 17.5 cm (7 inch) calcium silicate brick wall offers about 51 dB.
From a purely logical perspective, I would assume that if sound can pass through both the wall and the window (when the wall provides insufficient sound insulation), the overall noise level is higher than if only the window is the weakest point allowing sound to pass through. Although the human ear and brain tend to attribute the sound primarily to the window, since it is the main source, sound passing through the wall is lower but spreads over a larger area, causing a cumulative effect of very low "noise" adding up.
For example, if 12 dB passes through the windows and only 2 dB through the wall, this would result in a combined total of approximately 12.x dB. This is my purely logical assumption, as I am not an expert in the field.
I also found a calculator that estimates combined sound levels from multiple sources, which seems to support my view: 12 dB and 2 dB add up to 12.413 dB.
Let’s assume a window with 32 dB sound insulation and a wall with 46 dB. If the outside noise level is 75 dB (e.g., from a car), then 43 dB passes through the window and 29 dB through the wall. According to the calculator, the combined level is 43.169 dB. However, since the wall has a significantly larger surface area, I estimate:
1 × 43 dB + 4 × 29 dB = 43.64 dB. If the wall’s area were seven times larger, the total would be about 44 dB.
If a better window with 39 dB insulation is installed, the numbers change to 1 × 36 dB + 4 × 29 dB = 38.547 dB.
Of course, there are certainly many other factors that could absorb or reflect sound. It would be great if a knowledgeable forum member from this field could clarify this further.
From a purely logical perspective, I would assume that if sound can pass through both the wall and the window (when the wall provides insufficient sound insulation), the overall noise level is higher than if only the window is the weakest point allowing sound to pass through. Although the human ear and brain tend to attribute the sound primarily to the window, since it is the main source, sound passing through the wall is lower but spreads over a larger area, causing a cumulative effect of very low "noise" adding up.
For example, if 12 dB passes through the windows and only 2 dB through the wall, this would result in a combined total of approximately 12.x dB. This is my purely logical assumption, as I am not an expert in the field.
I also found a calculator that estimates combined sound levels from multiple sources, which seems to support my view: 12 dB and 2 dB add up to 12.413 dB.
Let’s assume a window with 32 dB sound insulation and a wall with 46 dB. If the outside noise level is 75 dB (e.g., from a car), then 43 dB passes through the window and 29 dB through the wall. According to the calculator, the combined level is 43.169 dB. However, since the wall has a significantly larger surface area, I estimate:
1 × 43 dB + 4 × 29 dB = 43.64 dB. If the wall’s area were seven times larger, the total would be about 44 dB.
If a better window with 39 dB insulation is installed, the numbers change to 1 × 36 dB + 4 × 29 dB = 38.547 dB.
Of course, there are certainly many other factors that could absorb or reflect sound. It would be great if a knowledgeable forum member from this field could clarify this further.
H
hauspeter15 Jun 2020 00:02Teemoe86 schrieb:
43dB passes through the window, and 29dB through the wall. According to the calculator, adding the levels gives 43.169dB. Why is the wall and window combined louder than just the window alone? How do you add different sound sources without considering interference? Sound waves can either amplify or cancel each other out. Noise-canceling headphones work using interference by producing opposing sound waves.
hauspeter schrieb:
Why is the wall and window louder than just the window?Because an online calculator said so – you’re not seriously suggesting that the internet would lie?https://www.instagram.com/11antgmxde/
https://www.linkedin.com/company/bauen-jetzt/
People, that’s why I clearly stated that I have no expertise in this topic and that I hope someone who is a professional in this field can contribute more to this assumption. I never claimed that it is true.
Please don’t read only half of the text—I explicitly wrote this before and after because I never intended to create the expectation that this statement has to be correct—it remains my hypothesis, and I hope someone else will correct me.
For noise-canceling headphones to achieve this, microphones must capture the ambient noise, process it in “real time,” and play back an “opposite pattern.” This way, incoming sounds are “canceled out” for the human ear. A wall cannot do this so easily.
Luxury cars have long used similar technology to make the interior quieter. Something like this might one day be available for single-family homes. However, the “counter-sound” would have to be so precisely matched that I currently consider it unlikely. But again, I am not an expert and welcome corrections from others.
And please don’t tell me that if I have no idea, I should simply not write anything… as long as I or someone else states that it is a hypothesis and not a confirmed fact, I believe it actually helps us get closer to the truth.
I hope I have clarified this.
Teemoe86 schrieb:
So this is my purely logical assumption. Since I’m not an expert...
Teemoe86 schrieb:
Of course, there are certainly many other factors that might absorb or reflect sound, etc.
It would be great if a knowledgeable forum member in this field could clarify.
Please don’t read only half of the text—I explicitly wrote this before and after because I never intended to create the expectation that this statement has to be correct—it remains my hypothesis, and I hope someone else will correct me.
hauspeter schrieb:I mentioned that as well, that there are other factors not taken into account here that can absorb or reflect sound.
Sound waves can reinforce or reduce each other.
For noise-canceling headphones to achieve this, microphones must capture the ambient noise, process it in “real time,” and play back an “opposite pattern.” This way, incoming sounds are “canceled out” for the human ear. A wall cannot do this so easily.
Luxury cars have long used similar technology to make the interior quieter. Something like this might one day be available for single-family homes. However, the “counter-sound” would have to be so precisely matched that I currently consider it unlikely. But again, I am not an expert and welcome corrections from others.
And please don’t tell me that if I have no idea, I should simply not write anything… as long as I or someone else states that it is a hypothesis and not a confirmed fact, I believe it actually helps us get closer to the truth.
I hope I have clarified this.
Now I have checked our construction folders.
Exterior wall with plaster, 42cm (17 inches), filled with expanded clay, sound insulation rating 53dB, U-value 0.18 W/m2K.
Window glass 36dB, the overall window element rating is not available, U-value 1.0, glass U-value 0.6.
The house feels well insulated and quiet.
Regards, Nida35a
Exterior wall with plaster, 42cm (17 inches), filled with expanded clay, sound insulation rating 53dB, U-value 0.18 W/m2K.
Window glass 36dB, the overall window element rating is not available, U-value 1.0, glass U-value 0.6.
The house feels well insulated and quiet.
Regards, Nida35a
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