ᐅ Exterior wall with ETICS or exterior wall with lightweight render?
Created on: 24 Nov 2013 17:35
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malu82
Hello everyone,
a great forum. I have already gained a lot of useful background information. THANK YOU!
We want to build a 1.5-story house, 135m² (1,453 sq ft), with a gas condensing boiler and solar thermal collectors, underfloor heating on the ground and upper floors, and a chimney flue. Two rooms on the upper floor, as well as the living room and guest room, face south. The plot (750m² (8,073 sq ft)) is located in a lightly developed residential area adjoining farmland. KfW 70 energy efficiency standard is not planned (or is it an option?).
Currently, I am wondering whether to build with:
24cm (9.5 inches) porous hollow bricks plus 8.0cm (3 inches) insulation (polystyrene rigid foam boards), reinforcing layer, and finishing render
or with
36.5cm (14 inches) porous hollow bricks and 2.0cm (0.8 inches) lightweight plaster with fiberglass mesh reinforcement.
Could someone possibly give me a general recommendation or explain the difference? Is the first option sufficient? Do I understand the second option as a monolithic construction where no additional insulation is needed due to the brick thickness?
Unfortunately, we have experienced mold and moisture damage in our previous apartment. I’ve read repeatedly that the first option often causes problems with moisture diffusion. For example, we always sleep with the window open at night. What option would cause us fewer concerns in this respect? Would a ventilation system then be a must?
I know I’m not a professional, and I understand that this can’t be generalized, but I hope you can provide a few tips or information.
Thank you very much and best regards
Marcel
a great forum. I have already gained a lot of useful background information. THANK YOU!
We want to build a 1.5-story house, 135m² (1,453 sq ft), with a gas condensing boiler and solar thermal collectors, underfloor heating on the ground and upper floors, and a chimney flue. Two rooms on the upper floor, as well as the living room and guest room, face south. The plot (750m² (8,073 sq ft)) is located in a lightly developed residential area adjoining farmland. KfW 70 energy efficiency standard is not planned (or is it an option?).
Currently, I am wondering whether to build with:
24cm (9.5 inches) porous hollow bricks plus 8.0cm (3 inches) insulation (polystyrene rigid foam boards), reinforcing layer, and finishing render
or with
36.5cm (14 inches) porous hollow bricks and 2.0cm (0.8 inches) lightweight plaster with fiberglass mesh reinforcement.
Could someone possibly give me a general recommendation or explain the difference? Is the first option sufficient? Do I understand the second option as a monolithic construction where no additional insulation is needed due to the brick thickness?
Unfortunately, we have experienced mold and moisture damage in our previous apartment. I’ve read repeatedly that the first option often causes problems with moisture diffusion. For example, we always sleep with the window open at night. What option would cause us fewer concerns in this respect? Would a ventilation system then be a must?
I know I’m not a professional, and I understand that this can’t be generalized, but I hope you can provide a few tips or information.
Thank you very much and best regards
Marcel
B
Bauexperte25 Nov 2013 13:58Hello,
Both types of render can be treated with a fungicidal and algicidal coating; then the "green" side stands no chance in the long run.
Best regards, Bauexperte
DerBjoern schrieb:What makes you say that?
The fact that monolithic walls do not develop algae is due to their lower U-values in PRACTICE.
DerBjoern schrieb:One is a synthetic resin render, the other a mineral-based render. I’m not an expert, but I hardly think that 2.5 cm (1 inch) of one warms up faster or slower than that thickness of the other render.
The render on ETICS cools down faster but also warms up faster again.
Both types of render can be treated with a fungicidal and algicidal coating; then the "green" side stands no chance in the long run.
Best regards, Bauexperte
D
DerBjoern25 Nov 2013 14:06Bauexperte schrieb:
Hello,
How do you come to that conclusion?With the same indoor and outdoor temperatures and identical U-value, the surface temperatures on the exterior should be the same. So if algae growth is related to surface temperature, then...
One is a synthetic resin-based render, the other a mineral-based plaster. I’m not an expert, but I hardly think that 2.5 cm (1 inch) of one would warm up faster or slower than the other plaster.It depends on the specific heat capacity of the plasters...
Both types of render can, by the way, be treated with a fungicide/algaecide coating; then the "green" side wouldn’t stand a chance in the long run.True, but some consider that bad while they at the same time treat their patios and walkways with algae remover from Aldi and tackle weeds with Vorox 😉
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AallRounder25 Nov 2013 14:19DerBjoern schrieb:
With the same indoor and outdoor temperature and identical U-value, the surface temperatures on the exterior should be the same. That is exactly not the case because the ETICS wall in the Fraunhofer test series cools below that. They certainly did not compare apples with oranges. The fundamental problem is the lack of thermal mass in the expanded polystyrene systems.
It’s unfortunate that I’m not allowed to share the link, but the report should be easy to find by searching online... It also mentions that fungicides are not a cure-all, as they are washed out faster on the weather-exposed side than they can actually act in their soluble form.
Hello AallRounder,
post the link; I’ll take responsibility for it 😎
Regards, BuildingExpert
BuildingExpert
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DerBjoern25 Nov 2013 14:28The document from the Fraunhofer Institute is well known to me...
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AallRounder25 Nov 2013 14:34Hello building expert,
... principle discussion ... no, I really didn't want to start that. Just wanted to present a few facts. That’s why I have (hopefully) left out my personal assessment.
... principle discussion ... no, I really didn't want to start that. Just wanted to present a few facts. That’s why I have (hopefully) left out my personal assessment.
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