Hello everyone,
I often read about the concept of "breathing walls."
Statements like:
- "We were told not to insulate because otherwise my 31cm (12 inch) brick wall won’t be able to breathe anymore."
- "We don’t need a ventilation system; the timber frame wall has no membrane, so it can breathe well."
- "We have a vapor-permeable wall, so moisture can escape outside, and I don’t need a ventilation system."
- "The wall is vapor-permeable, a ventilation system is not necessary, and you basically don’t need to ventilate."
I keep seeing these and similar sentences online and have even heard them personally from house building companies—the latest just this Monday. Other opinions include: Don’t put photovoltaics on the roof due to too much electromagnetic pollution. He would never install a ventilation system. Climate change? That doesn’t even exist. At some point, I just got up and left.
I’m an engineer, not involved in house building. But in my opinion, these statements make no sense at all.
A wall can never really "breathe" properly.
Here, "breathing" means a significant moisture exchange.
How is this supposed to work physically? It’s not a thin membrane, but a thick, solid wall or one filled with insulation.
Sure, a certain amount of moisture transfer always occurs. But in my view, this is absolutely negligible. There is no way that the few liters of moisture produced daily in a single-family house could pass through the wall to the outside without either a ventilation system or manual ventilation. Physically, this just can’t happen.
Of course, it’s different with older houses. They have numerous leaks that allow air and moisture exchange. But modern houses are sealed tightly. Therefore, there is no real air exchange through the walls.
And beyond the aspect of "removing moisture to the outside," there is also the aspect of "bringing fresh air into the house."
My point is not to argue for or against ventilation systems. I am in favor, but it can also work without one if you don’t want it—just with regular manual airing, in my opinion.
What do you think? Do these "breathing walls" really exist?
Am I completely wrong? Or is this myth just incredibly persistent among home builders and even building companies?
Best regards,
Specki
I often read about the concept of "breathing walls."
Statements like:
- "We were told not to insulate because otherwise my 31cm (12 inch) brick wall won’t be able to breathe anymore."
- "We don’t need a ventilation system; the timber frame wall has no membrane, so it can breathe well."
- "We have a vapor-permeable wall, so moisture can escape outside, and I don’t need a ventilation system."
- "The wall is vapor-permeable, a ventilation system is not necessary, and you basically don’t need to ventilate."
I keep seeing these and similar sentences online and have even heard them personally from house building companies—the latest just this Monday. Other opinions include: Don’t put photovoltaics on the roof due to too much electromagnetic pollution. He would never install a ventilation system. Climate change? That doesn’t even exist. At some point, I just got up and left.
I’m an engineer, not involved in house building. But in my opinion, these statements make no sense at all.
A wall can never really "breathe" properly.
Here, "breathing" means a significant moisture exchange.
How is this supposed to work physically? It’s not a thin membrane, but a thick, solid wall or one filled with insulation.
Sure, a certain amount of moisture transfer always occurs. But in my view, this is absolutely negligible. There is no way that the few liters of moisture produced daily in a single-family house could pass through the wall to the outside without either a ventilation system or manual ventilation. Physically, this just can’t happen.
Of course, it’s different with older houses. They have numerous leaks that allow air and moisture exchange. But modern houses are sealed tightly. Therefore, there is no real air exchange through the walls.
And beyond the aspect of "removing moisture to the outside," there is also the aspect of "bringing fresh air into the house."
My point is not to argue for or against ventilation systems. I am in favor, but it can also work without one if you don’t want it—just with regular manual airing, in my opinion.
What do you think? Do these "breathing walls" really exist?
Am I completely wrong? Or is this myth just incredibly persistent among home builders and even building companies?
Best regards,
Specki
If the wall needs to breathe, just tilt the window open.
There was (was) this fanatic named Konrad Fischer, who strongly promoted such ideas. He has since passed away, but his ideas still linger.
The whole fuss is basically based on the Lichtenfelser experiment – which supposedly “proves” that insulation doesn’t work. From there come arguments like “building like in the old days” and “expensive, health-damaging mechanical systems with air conditioning and ventilation instead of simple window ventilation like in the past.”
He then writes things like, “A famous example of the brazen attack on the national economy and public health through what Edgar Gärtner revealed in ‘Ökonihilismus 2012’ as the suicide program of eco-parasites and their superstitious followers everywhere through passive house construction[…]”
There was (was) this fanatic named Konrad Fischer, who strongly promoted such ideas. He has since passed away, but his ideas still linger.
The whole fuss is basically based on the Lichtenfelser experiment – which supposedly “proves” that insulation doesn’t work. From there come arguments like “building like in the old days” and “expensive, health-damaging mechanical systems with air conditioning and ventilation instead of simple window ventilation like in the past.”
He then writes things like, “A famous example of the brazen attack on the national economy and public health through what Edgar Gärtner revealed in ‘Ökonihilismus 2012’ as the suicide program of eco-parasites and their superstitious followers everywhere through passive house construction[…]”
D
Davidoff866 Mar 2020 09:21Apart from the fact that personal perception ALWAYS influences one’s own reasoning (for me, on the topic of wooden houses, but also in other areas like cars, coronavirus, nutrition?), I am actually quite open and willing to learn.
Would you, @Tego12 and @Mycraft, please explain to me in simple terms for laypeople (unfortunately, I am not a physicist, just a humanities scholar) why the claim that a wooden wall, unlike a wall made of bricks, is climate-regulating is nonsense, as told by promoters of wood construction?
I am serious. Ultimately, planning a house is a huge project and we want to make a good decision.
Thank you.
Would you, @Tego12 and @Mycraft, please explain to me in simple terms for laypeople (unfortunately, I am not a physicist, just a humanities scholar) why the claim that a wooden wall, unlike a wall made of bricks, is climate-regulating is nonsense, as told by promoters of wood construction?
I am serious. Ultimately, planning a house is a huge project and we want to make a good decision.
Thank you.
You need to ventilate a solid wood house!
Our experience after 2 years.
Our builder also says it is diffusion-permeable but insists that a ventilation system, controlled mechanical ventilation, or even window seals are not necessary.
In summer, our ventilation system often switches off, which keeps the house nicely cool. However, the humidity rises and eventually the air gets stale. It becomes really muggy, even though the temperature outside is sometimes more than 10°C (18°F) cooler.
The fact is, since we moved in, our little one no longer has pseudocroup attacks. Whatever the reason may be.
Our experience after 2 years.
Our builder also says it is diffusion-permeable but insists that a ventilation system, controlled mechanical ventilation, or even window seals are not necessary.
In summer, our ventilation system often switches off, which keeps the house nicely cool. However, the humidity rises and eventually the air gets stale. It becomes really muggy, even though the temperature outside is sometimes more than 10°C (18°F) cooler.
The fact is, since we moved in, our little one no longer has pseudocroup attacks. Whatever the reason may be.
Davidoff86 schrieb:
Apart from the fact that personal feelings ALWAYS influence one's own rationality (for me, when it comes to timber houses, but also with other topics? Cars, coronavirus, nutrition?), I am actually quite open and willing to be educated. Would you @Tego12 and @Mycraft please help me with simple explanations for laypeople (unfortunately, I am not a physicist, just a humanities scholar ) to describe why the claim that a wooden wall, unlike a brick wall, regulates the climate is nonsense, spread by promoters?
I am serious. Ultimately, designing a house is a huge project, and we want to make a good decision.
Thank you all Unfortunately, that is not possible... because every superficial argument is countered by conspiracy theorists with further meaningless arguments (which always sound very plausible to laypeople), as this is the principle behind conspiracy theories and it works very well.
The simplest explanation for me is always this: According to the energy saving regulation, there are requirements for airtightness. In most houses, this is also proven by a blower door test (including timber houses...). It is thus confirmed that these houses are "airtight," there is no relevant or sufficient air exchange (clearly defined in DIN 1946-6 and required by the energy saving regulation), and this must be ensured otherwise (ventilation system, airing out, etc.).
By choosing appropriate wall materials (clay plaster plus vapor-permeable paint, for example), there are certainly some possibilities to slightly buffer moisture (inside the house!!), but the effect is very small, and it does not provide any fresh oxygen.
N
nordanney6 Mar 2020 09:36Davidoff86 schrieb:
why the claim that a wooden wall, unlike a wall made of bricks, is climate regulating is nonsense, which is told by promoters?Let’s turn the tables for a moment. Please explain to us why a wooden wall is climate regulating compared to a brick wall. How does the moisture get out of the house?
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