ᐅ Single-Wall Masonry vs. Cavity Wall with External Thermal Insulation Composite System (ETICS)
Created on: 3 Jul 2011 22:01
W
Wallace
I am planning to build a KfW70 semi-detached house with an air-source heat pump.
I can choose between the following two options:
- 36.5 cm (14.4 inches) masonry made of aerated concrete or Poroton brick
- 17.5 cm (6.9 inches) Ytong / hollow brick plus 10–12 cm (4–5 inches) external insulation system
What do you see as the advantages and disadvantages? The necessary insulation should be achieved with both systems. An energy demand calculation will be done beforehand, and KfW70 certification is guaranteed.
I think the second option has the advantage of thinner walls (7–9 cm (3–4 inches) more interior space), no risk of water freezing within the masonry (>0°C (32°F)), the masonry is exposed to smaller temperature fluctuations and is therefore better protected against deformation and cracks, and better sound insulation due to the external insulation system.
Disadvantages: the external insulation system is less resistant to mechanical stress.
Advantages of the 36.5 cm (14.4 inches) masonry: faster construction, greater thermal mass/volume resulting in a more comfortable indoor climate (temperature and humidity).
These are some assumptions I have made. What about the costs?
I can choose between the following two options:
- 36.5 cm (14.4 inches) masonry made of aerated concrete or Poroton brick
- 17.5 cm (6.9 inches) Ytong / hollow brick plus 10–12 cm (4–5 inches) external insulation system
What do you see as the advantages and disadvantages? The necessary insulation should be achieved with both systems. An energy demand calculation will be done beforehand, and KfW70 certification is guaranteed.
I think the second option has the advantage of thinner walls (7–9 cm (3–4 inches) more interior space), no risk of water freezing within the masonry (>0°C (32°F)), the masonry is exposed to smaller temperature fluctuations and is therefore better protected against deformation and cracks, and better sound insulation due to the external insulation system.
Disadvantages: the external insulation system is less resistant to mechanical stress.
Advantages of the 36.5 cm (14.4 inches) masonry: faster construction, greater thermal mass/volume resulting in a more comfortable indoor climate (temperature and humidity).
These are some assumptions I have made. What about the costs?
E.Curb schrieb:
...I’m not referring to the outside basement wall I thought the structure would be from the outside in: perimeter insulation, concrete, then calcium silicate bricks.
But do you still need calcium silicate bricks on the inside? How thick would that be? If you only have 6m (20 feet) for a semi-detached house, every lost centimeter (inch) is frustrating.
Bauexperte schrieb:
Hello,
Rather 10 cm (5 inches), but you are also putting 10 cm (5 inches) of external thermal insulation composite system (ETICS) in front of the masonry, and the outlook—if the tightening of the energy saving regulations continues like this in the coming years—is that you may have to dispose of this system as hazardous waste at a high cost before you can implement further energy-saving measures. If you choose the 36.5 cm (14.4 inches) aerated concrete blocks, these potential costs do not arise, since you can apply additional insulation materials without further demolition work.Is there a discussion about ETICS being banned soon and treated like asbestos? This is about a semi-detached house, 6 m (19.7 feet) wide. You have to leave 3 m (9.8 feet) space to the neighbor. I would build so that I fully utilize the maximum width. How am I supposed to add an insulation layer later if I use the 36.5 cm (14.4 inches) aerated concrete blocks? Or is it common to leave a 10 cm (5 inches) buffer to allow for future upgrades?
I don’t want to have to do anything with the insulation for the next 25 years. Ideally, even longer.
B
Bauexperte4 Jul 2011 13:50Excerpt from what I consider a good article from FAZnet dated 16.11.2010:
"There is no topic currently causing more controversy than thermal insulation for buildings...
.
The Hysteria of Sealing Off
Germans have surprisingly and casually abandoned the solidity of their buildings. At the same time, and this is an almost perverse contradiction, the tendency toward complete enclosure has become pathological. Every child is sternly warned that if they put a plastic bag over their head, they will suffocate and die. The same principle basically applies to houses. Let nothing in and nothing out, sealing off, bell jar ideology: full thermal insulation also reflects the collective psychological profile of a society that harbors panicked fears of intruders and infections. However, this very hysterical sealing off against everything external conflicts with another deeply rooted German fear: that of mold.
This is the paradox of German insulation today, which is already visible on a large scale: mold grows indoors because moisture cannot escape, while outside woodpeckers peck holes in the insulation boards and build nests in the polystyrene. However, these contradictions cannot stop the German insulation craze, not least because its character is that of a messianic mission: The global climate shall be healed through German insulation systems.
The Cloaking of an Economic Advantage
The components of houses sealed in with external thermal insulation composite systems are no less environmentally unfriendly: To protect the climate, entire oil fields are transformed with enormous effort into polystyrene rigid foam, extruded polystyrene foam, or polyurethane rigid foam; it is plastic, which, behind the render, is supposed to ensure ecological correctness as an insulating material. Full thermal insulation, intended to protect the climate, is therefore already part of the global energy problem it aims to solve – a fact stubbornly ignored, behind which lie other, purely commercial interests.
It is worth considering the interests of the so-called tradespeople in the debate about full thermal insulation. Building a classic double-skin, climate- and breathable brick wall costs time and money. For the general contractor, profit margins are much higher with a building constructed using external thermal insulation composite systems: Anyone who has seen how quickly a small team of bricklayers erects a wall with suitcase-sized industrial bricks; how rapidly insulation boards are then either mechanically fixed or often also glued (yes, glued – regards to the climate activists) to this wall, before a group of inexperienced plasterers armed with spray guns applies reinforcement mortar and finishing plaster in just a few hours: Anyone who realizes that a whole house can be built this way five times faster but still costs almost as much as a traditional brick building will understand why almost all construction is now done this way: The ecological aspect merely serves to cloak an economic advantage.
In Ten Years, It Will All Come Down
The most visible success of full thermal insulation on houses is the fact that the head plasterer arrives for damage inspection in the latest Porsche Cayenne when the whole mess becomes damp or falls off after a short time; full insulation mainly helps the wallets of construction companies.
“Sustainable,” the second important word without which nothing can be built today, this is certainly not sustainable: Unlike vacuum-sealed cheese, the plastic-coated house is not known for great durability. It is quite certain that in ten years the entire world of new buildings will be a house-shaped hazardous waste landfill: The polystyrene boards swell, condensation forms between the insulation and the outer render, which cannot fully evaporate due to the high water vapor diffusion resistance of the render and paint. The render cracks, the insulation slowly becomes damp, loses its insulating effect, and in ten years everything will come off, often by itself. Until recently, façades were among the few building elements that could not and did not have to be discarded; full thermal insulation changes that...."
"There is no topic currently causing more controversy than thermal insulation for buildings...
.
The Hysteria of Sealing Off
Germans have surprisingly and casually abandoned the solidity of their buildings. At the same time, and this is an almost perverse contradiction, the tendency toward complete enclosure has become pathological. Every child is sternly warned that if they put a plastic bag over their head, they will suffocate and die. The same principle basically applies to houses. Let nothing in and nothing out, sealing off, bell jar ideology: full thermal insulation also reflects the collective psychological profile of a society that harbors panicked fears of intruders and infections. However, this very hysterical sealing off against everything external conflicts with another deeply rooted German fear: that of mold.
This is the paradox of German insulation today, which is already visible on a large scale: mold grows indoors because moisture cannot escape, while outside woodpeckers peck holes in the insulation boards and build nests in the polystyrene. However, these contradictions cannot stop the German insulation craze, not least because its character is that of a messianic mission: The global climate shall be healed through German insulation systems.
The Cloaking of an Economic Advantage
The components of houses sealed in with external thermal insulation composite systems are no less environmentally unfriendly: To protect the climate, entire oil fields are transformed with enormous effort into polystyrene rigid foam, extruded polystyrene foam, or polyurethane rigid foam; it is plastic, which, behind the render, is supposed to ensure ecological correctness as an insulating material. Full thermal insulation, intended to protect the climate, is therefore already part of the global energy problem it aims to solve – a fact stubbornly ignored, behind which lie other, purely commercial interests.
It is worth considering the interests of the so-called tradespeople in the debate about full thermal insulation. Building a classic double-skin, climate- and breathable brick wall costs time and money. For the general contractor, profit margins are much higher with a building constructed using external thermal insulation composite systems: Anyone who has seen how quickly a small team of bricklayers erects a wall with suitcase-sized industrial bricks; how rapidly insulation boards are then either mechanically fixed or often also glued (yes, glued – regards to the climate activists) to this wall, before a group of inexperienced plasterers armed with spray guns applies reinforcement mortar and finishing plaster in just a few hours: Anyone who realizes that a whole house can be built this way five times faster but still costs almost as much as a traditional brick building will understand why almost all construction is now done this way: The ecological aspect merely serves to cloak an economic advantage.
In Ten Years, It Will All Come Down
The most visible success of full thermal insulation on houses is the fact that the head plasterer arrives for damage inspection in the latest Porsche Cayenne when the whole mess becomes damp or falls off after a short time; full insulation mainly helps the wallets of construction companies.
“Sustainable,” the second important word without which nothing can be built today, this is certainly not sustainable: Unlike vacuum-sealed cheese, the plastic-coated house is not known for great durability. It is quite certain that in ten years the entire world of new buildings will be a house-shaped hazardous waste landfill: The polystyrene boards swell, condensation forms between the insulation and the outer render, which cannot fully evaporate due to the high water vapor diffusion resistance of the render and paint. The render cracks, the insulation slowly becomes damp, loses its insulating effect, and in ten years everything will come off, often by itself. Until recently, façades were among the few building elements that could not and did not have to be discarded; full thermal insulation changes that...."
Hello,
No, I wasn’t referring to the basement at all. I meant the exterior walls of the ground floor and upper floor. Why do you only consider aerated concrete and clay blocks as options? If you value sound insulation and thermal mass, sand-lime brick is actually a very good alternative.
However, it is important that the overall concept is right. There isn’t one ideal exterior wall that is the best choice for every house.
Regards
Wallace schrieb:
I thought the construction was from outside to inside: perimeter insulation, concrete, sand-lime brick. But do you still need sand-lime brick on the inside? How thick would that be? If you only have 6m (20 feet) for a semi-detached house, every lost centimeter (inch) is frustrating.
No, I wasn’t referring to the basement at all. I meant the exterior walls of the ground floor and upper floor. Why do you only consider aerated concrete and clay blocks as options? If you value sound insulation and thermal mass, sand-lime brick is actually a very good alternative.
However, it is important that the overall concept is right. There isn’t one ideal exterior wall that is the best choice for every house.
Regards
H
Häuslebauer401 Sep 2012 17:24The article really resonates with me.
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