ᐅ Materials for Exterior and Interior Walls (KfW 55 Standard)
Created on: 13 Aug 2021 14:16
B
Baumeister86
Dear all,
After initial discussions with local general contractors and reviewing construction specifications, some questions arose regarding the wall materials (assembly).
We would like to build to the KfW 55 standard, as it doesn’t seem to deviate much from the usual practice. Additionally, we want good sound insulation (unfortunately, the air traffic from BER airport can still be heard in eastern Berlin, even though planes will not fly directly over us). Therefore, I am a bit overwhelmed by the many exterior wall options.
Monolithic construction seems advantageous to me, as masonry should last much longer than external thermal insulation composite systems (ETICS) and require less maintenance. Are there any reliable experiences with ETICS? Also, I’m a bit unsure about calcium silicate brick (best sound insulation, but I don’t want sand falling down every time I drill). How is the maintenance of facade render handled? I cannot recall my parents having that done in almost 30 years (house built in the late 1970s).
Porous concrete with a wall thickness of 36.5 cm (14 inches) should meet KfW requirements (U-value <0.2), while clay blocks require additional filling with perlite. However, from what I have researched, sound insulation of clay blocks is better than porous concrete, at least on paper. How does this compare in practice?
Lightweight expanded clay aggregate blocks were also offered to us (however, as a pre-assembled system wall). You would need a lot of ETICS on this to meet the KfW standard—how is the sound insulation in this case?
Most importantly, what are the costs of these options (calcium silicate brick + ETICS vs. porous concrete vs. insulated clay blocks) for, say, a city villa with a 10 x 10 m (33 x 33 ft) footprint? Most general contractors work only with one option or the other (and I have not yet found any insulated clay blocks).
To avoid noise transmission inside the house, regular clay block walls seem reasonable (12 cm or 24 cm [5 or 10 inches] if load-bearing). Calcium silicate bricks seem somewhat heavy (and the sand issue)?
Thank you very much for your opinions.
Stephan
P.S.: Are we really looking at 2100–2500 €/m² (195–230 $/ft²) for a “normal standard” house now in Brandenburg? Or did we consult the wrong general contractors?
After initial discussions with local general contractors and reviewing construction specifications, some questions arose regarding the wall materials (assembly).
We would like to build to the KfW 55 standard, as it doesn’t seem to deviate much from the usual practice. Additionally, we want good sound insulation (unfortunately, the air traffic from BER airport can still be heard in eastern Berlin, even though planes will not fly directly over us). Therefore, I am a bit overwhelmed by the many exterior wall options.
Monolithic construction seems advantageous to me, as masonry should last much longer than external thermal insulation composite systems (ETICS) and require less maintenance. Are there any reliable experiences with ETICS? Also, I’m a bit unsure about calcium silicate brick (best sound insulation, but I don’t want sand falling down every time I drill). How is the maintenance of facade render handled? I cannot recall my parents having that done in almost 30 years (house built in the late 1970s).
Porous concrete with a wall thickness of 36.5 cm (14 inches) should meet KfW requirements (U-value <0.2), while clay blocks require additional filling with perlite. However, from what I have researched, sound insulation of clay blocks is better than porous concrete, at least on paper. How does this compare in practice?
Lightweight expanded clay aggregate blocks were also offered to us (however, as a pre-assembled system wall). You would need a lot of ETICS on this to meet the KfW standard—how is the sound insulation in this case?
Most importantly, what are the costs of these options (calcium silicate brick + ETICS vs. porous concrete vs. insulated clay blocks) for, say, a city villa with a 10 x 10 m (33 x 33 ft) footprint? Most general contractors work only with one option or the other (and I have not yet found any insulated clay blocks).
To avoid noise transmission inside the house, regular clay block walls seem reasonable (12 cm or 24 cm [5 or 10 inches] if load-bearing). Calcium silicate bricks seem somewhat heavy (and the sand issue)?
Thank you very much for your opinions.
Stephan
P.S.: Are we really looking at 2100–2500 €/m² (195–230 $/ft²) for a “normal standard” house now in Brandenburg? Or did we consult the wrong general contractors?
11ant schrieb:
You won’t be able to meet the energy saving ordinance using sand-lime brick without external thermal insulation composite systems (ETICS), so here we are again at the crucial question: how do you want to approach this from a fundamental perspective?We are building to KfW 55 standard using sand-lime brick without ETICS. 😉 Well, there is an outer shell made of attractive facing bricks, but that wasn’t explicitly ruled out here, was it?B
Baumeister8616 Aug 2021 16:56motorradsilke schrieb:
We had our old house demolished. It was about 80 sqm (860 sq ft) plus a small basement of about 8 sqm (85 sq ft). However, we cleared out the interior ourselves because the doors, windows, and roof covering (metal sheets) are still being used by my sons for sheds and animal shelters. For the demolition of the remaining masonry and backfilling, we paid around 20,000 euros.
We could have had it done cheaper (14,000 euros), but we wanted the contractor who is also building the new house to handle it. On one hand, because the process needed to be seamless and continuous (we need to finish as soon as possible since we currently live in a container on the property), and on the other hand, so that in case of any issues (cracks or similar in the masonry), one party can’t blame the other. Wow, that sounds quite different from the 30,000–35,000 euros estimated without inspection by one of the house builders for us.
If you’re still living in a construction trailer right now, I totally understand that. We feel the same way – having everything from one source would be an advantage so no one can pass the blame. But so far, we haven’t found anyone who will do both demolition and construction (only builders for the construction and recommendations for demolition). May I ask who you are working with, @motorradsilke?
@Acof1978, in talks with the first two general contractors, the chimney, electric blinds, and KfW-55 standard (energy-efficient standard, similar to Passive House) were included (townhouse with 2.5 m (8 ft) ceiling height) at this price per sqm. One builds according to the scope of work description, but unfortunately does not include a garage or terrace, and the other ignores my request for a scope of work description. So I can’t say much more.
Neither wants to do the demolition… so it’s a bit difficult at the moment.
K1300S schrieb:
Our sand-lime brick walls are 15 cm (6 inches) thick both inside and outside.K1300S schrieb:
We are building to KfW 55 standard using sand-lime bricks without external thermal insulation composite systems (ETICS). 😉 Well, there is also a facing layer of attractive brick veneer, but that wasn’t explicitly excluded here, right?15 cm (6 inches) sand-lime brick plus brick veneer, nothing in between, no air cavity, no mineral wool or anything like that?https://www.instagram.com/11antgmxde/
https://www.linkedin.com/company/bauen-jetzt/
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