ᐅ Exterior wall with ETICS or exterior wall with lightweight render?
Created on: 24 Nov 2013 17:35
M
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 16:14Hello,
This is a “Jehovah” topic – what did you expect 😀
We reject building with EIFS for a variety of reasons; foremost among them is the senselessness of installing hazardous materials right on your own home. Of course, there are ecologically acceptable insulation materials – but currently (for now) no one wants to pay for them; that may still change. On the other hand, exterior wall insulation is unnecessary if the wall thickness or the thermal insulation properties of the masonry are sufficient. The issue of algae or bird nests then “only” appears as a nice side effect.
Architects and most suppliers like to work with a classic EIFS. They tell their clients that it is cheaper and that it helps to achieve better energy efficiency ratings for a single-family house. That’s all just a pretense. In reality – based on my experience – it is solely about avoiding discussions with homeowners regarding exterior settlement cracks, which inevitably occur. Of course, settlement cracks also appear in a single-family house wrapped in EIFS; but they occur behind the facade and are therefore not visible from the outside.
Now, of course, one can have a good debate about who is fooling whom here. But in the end, it is pointless as long as the bottom line price is the only thing that matters, rather than the total of the individual components of a quality single-family house built to last for years.
Best regards, Bauexperte
Mycraft schrieb:
Yes, and here we are again with the fundamental debate: EIFS (Exterior Insulation and Finish System) yes or no...
This is a “Jehovah” topic – what did you expect 😀
We reject building with EIFS for a variety of reasons; foremost among them is the senselessness of installing hazardous materials right on your own home. Of course, there are ecologically acceptable insulation materials – but currently (for now) no one wants to pay for them; that may still change. On the other hand, exterior wall insulation is unnecessary if the wall thickness or the thermal insulation properties of the masonry are sufficient. The issue of algae or bird nests then “only” appears as a nice side effect.
Architects and most suppliers like to work with a classic EIFS. They tell their clients that it is cheaper and that it helps to achieve better energy efficiency ratings for a single-family house. That’s all just a pretense. In reality – based on my experience – it is solely about avoiding discussions with homeowners regarding exterior settlement cracks, which inevitably occur. Of course, settlement cracks also appear in a single-family house wrapped in EIFS; but they occur behind the facade and are therefore not visible from the outside.
Now, of course, one can have a good debate about who is fooling whom here. But in the end, it is pointless as long as the bottom line price is the only thing that matters, rather than the total of the individual components of a quality single-family house built to last for years.
Best regards, Bauexperte
D
DerBjoern25 Nov 2013 16:26Bauexperte schrieb:
Hello,
Then I don’t understand your statement 😕
One person doesn’t believe apples and oranges are being compared, the other does...
[QUOTE]
Hazardous waste
[QUOTE]
Can we now please also include breathable walls?! Then we will have everything covered 🙄
B
Bauexperte25 Nov 2013 16:39Hello,
Best regards, Bauexperte
DerBjoern schrieb:I always see it as a confirmation of this forum’s purpose when users receive help. But before I get to the breathable walls, I want to mention the cost per square meter (sq m) of living space for good to very good quality under €1,000.00. Since this topic hasn’t been thoroughly discussed yet, you’ll probably have to wait a bit longer 😉
Can we please include the breathable walls now?! Then we would have everything covered 🙄
Best regards, Bauexperte
A
AallRounder25 Nov 2013 20:19The subject of this study is a heated test house constructed as part of the intentional IEA project Annex 24 (HAMTIE).
Figure 5 shows the west and south facades (windows) of the single-story house with a basement. The building envelope consists of various wall constructions with similar thermal transmittance values (U-values). The west wall (U = 0.41 W/m²K) features an 80 mm (3 inch) thick exterior insulation system (EIFS) on 240 mm (9.4 inch) calcium silicate masonry, while the sections facing north and south are monolithic walls (U = 0.51 W/m²K) made of 365 mm (14.4 inch) porous lightweight brick with white and red tinted plaster.
Correct! "Apples" --> EIFS U=0.41
"Pears" --> Brick wall U=0.51
This inaccuracy by the two engineers naturally invalidates the entire conclusion of the Fraunhofer study.
Figure 5 shows the west and south facades (windows) of the single-story house with a basement. The building envelope consists of various wall constructions with similar thermal transmittance values (U-values). The west wall (U = 0.41 W/m²K) features an 80 mm (3 inch) thick exterior insulation system (EIFS) on 240 mm (9.4 inch) calcium silicate masonry, while the sections facing north and south are monolithic walls (U = 0.51 W/m²K) made of 365 mm (14.4 inch) porous lightweight brick with white and red tinted plaster.
Correct! "Apples" --> EIFS U=0.41
"Pears" --> Brick wall U=0.51
This inaccuracy by the two engineers naturally invalidates the entire conclusion of the Fraunhofer study.
D
DerBjoern25 Nov 2013 21:09@Bauexperte
I guess with the 1000€/m² (about $1,100 per square yard) you’ll be quite busy 😀
@Aalrounder
0.41 W/m²K => 0.51 W/m²K
That means about 25% more energy is lost. With crucial temperature differences in the decimal range as indicated here, that can already have a significant impact. You can also see this with better thermally conductive anchors in external insulation systems, where no algae growth occurs.
Today’s monolithic wall constructions clearly achieve U-values below 0.2 W/m²K, which is quite different from the 30-year-old bricks used in this test. This can quickly lead to disappointment just a few years after moving in...
I guess with the 1000€/m² (about $1,100 per square yard) you’ll be quite busy 😀
@Aalrounder
0.41 W/m²K => 0.51 W/m²K
That means about 25% more energy is lost. With crucial temperature differences in the decimal range as indicated here, that can already have a significant impact. You can also see this with better thermally conductive anchors in external insulation systems, where no algae growth occurs.
Today’s monolithic wall constructions clearly achieve U-values below 0.2 W/m²K, which is quite different from the 30-year-old bricks used in this test. This can quickly lead to disappointment just a few years after moving in...
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