Dear forum community,
We have been quiet readers for some time now and are currently close to signing the construction contract. The plot was officially purchased last week.
At the moment, we are still considering two options: a solid (brick or block) house and a prefabricated house. We are now facing the difficult choice regarding the wall construction and building method:
(from outside to inside)
Prefabricated house (significantly above KfW 40+ standard, close to passive house): 5 mm (0.2 inch) exterior plaster, 100 mm (4 inch) external thermal insulation composite system (polystyrene), 12.5 mm (0.5 inch) Fermacell panels, 160 mm (6.3 inch) timber studs with insulation, 0.2 mm (0.008 inch) vapor retarder, 12.5 mm (0.5 inch) Fermacell panels, 80 mm (3.1 inch) timber studs with insulation, 12.5 mm (0.5 inch) Fermacell panels.
Solid house (Energy Saving Ordinance / EnEV standard): exterior plaster, 36.5 cm (14.4 inch) aerated concrete, interior plaster.
Now my two questions:
Which building method would you prefer and why?
Is it worthwhile to use double boarding with 2 x 12.5 mm (2 x 0.5 inch) Fermacell panels on all interior sides of the prefabricated house walls?
A building blog is currently in preparation. We look forward to sharing our construction experience and contributing back as previously quiet readers.
Best regards
Family schroedinxer
We have been quiet readers for some time now and are currently close to signing the construction contract. The plot was officially purchased last week.
At the moment, we are still considering two options: a solid (brick or block) house and a prefabricated house. We are now facing the difficult choice regarding the wall construction and building method:
(from outside to inside)
Prefabricated house (significantly above KfW 40+ standard, close to passive house): 5 mm (0.2 inch) exterior plaster, 100 mm (4 inch) external thermal insulation composite system (polystyrene), 12.5 mm (0.5 inch) Fermacell panels, 160 mm (6.3 inch) timber studs with insulation, 0.2 mm (0.008 inch) vapor retarder, 12.5 mm (0.5 inch) Fermacell panels, 80 mm (3.1 inch) timber studs with insulation, 12.5 mm (0.5 inch) Fermacell panels.
Solid house (Energy Saving Ordinance / EnEV standard): exterior plaster, 36.5 cm (14.4 inch) aerated concrete, interior plaster.
Now my two questions:
Which building method would you prefer and why?
Is it worthwhile to use double boarding with 2 x 12.5 mm (2 x 0.5 inch) Fermacell panels on all interior sides of the prefabricated house walls?
A building blog is currently in preparation. We look forward to sharing our construction experience and contributing back as previously quiet readers.
Best regards
Family schroedinxer
schroedinxer schrieb:
Thermal insulation is more of an economic issue for us. If it makes financial sense, then sure. But if it clearly results in a loss, then not. The solid construction house would be about €40,000 cheaper in this configuration and after considering the KfW subsidy. Living space approx. 210 m² (2260 sq ft) + 50 m² (540 sq ft) granny flat. By thermal insulation, I actually meant protection from heat. The temperature trend is rising, so this topic will likely become more important in the coming decades.
The type of wall construction is ultimately not that crucial; what matters are the technical properties.
A timber frame wall will provide excellent thermal insulation but a more than mediocre sound insulation and also poor protection against heat.
Aerated concrete will offer less insulation but somewhat better sound and thermal protection properties, although these will also likely be in the lower mid-range.
If I had a free choice, I wouldn’t decide on either wall construction. However, if only these two options are available, I would choose the monolithic wall, as it represents a better compromise and a simpler wall build (less prone to errors).
S
schroedinxer24 Nov 2019 09:54Thank you very much for your feedback.
Is aerated concrete really that much more resistant to water damage? I would insure against plumbing leaks and weather-related events, since the total investment is really quite high for us. Does this affect your assessment?
The comparison between apples and oranges comes from the fact that we asked both builders to provide offers with the best possible price-performance ratio. The solid brick builder said even KfW 55 energy standards wouldn’t be worthwhile. The prefab house is standard KfW 40, but we wanted a service cavity to avoid damaging the vapor barrier, so with an additional insulation layer we will be well below that. The “Plus” over KfW 40 was then no longer in question, since for two residential units, the photovoltaic system with battery storage is hardly affected by the additional €5,000 (EUR) per unit in subsidies. Of course, it also feels good to be as self-sufficient as possible given the current climate discussion, but we don’t prioritize that and see it more rationally.
The location is very good. About 12 km (7.5 miles) from the Daimler headquarters. So the location will certainly have an impact on any potential resale.
A really tough decision!
Is aerated concrete really that much more resistant to water damage? I would insure against plumbing leaks and weather-related events, since the total investment is really quite high for us. Does this affect your assessment?
The comparison between apples and oranges comes from the fact that we asked both builders to provide offers with the best possible price-performance ratio. The solid brick builder said even KfW 55 energy standards wouldn’t be worthwhile. The prefab house is standard KfW 40, but we wanted a service cavity to avoid damaging the vapor barrier, so with an additional insulation layer we will be well below that. The “Plus” over KfW 40 was then no longer in question, since for two residential units, the photovoltaic system with battery storage is hardly affected by the additional €5,000 (EUR) per unit in subsidies. Of course, it also feels good to be as self-sufficient as possible given the current climate discussion, but we don’t prioritize that and see it more rationally.
The location is very good. About 12 km (7.5 miles) from the Daimler headquarters. So the location will certainly have an impact on any potential resale.
A really tough decision!
S
schroedinxer24 Nov 2019 09:55-XIII- schrieb:
By thermal protection, I actually meant protection from heat. The temperature curve is rising, so this topic will probably become more important in the coming decades.
The type of wall construction is ultimately not that crucial; what matters are the technical characteristics.
A timber stud wall will provide excellent thermal insulation but rather poor sound insulation and also insufficient heat protection.
Aerated concrete will offer less insulation but somewhat better sound and heat protection properties, although these are likely to be only moderate.
If I had the free choice, I wouldn’t choose either of these wall constructions. If only these two options are available, then monolithic construction, as it is the better compromise and has a simpler wall structure (less prone to errors). What would you prefer? The builder of solid walls also offers other options for an additional charge.
We are currently building a multi-layered wall system (which is, however, the most expensive option). Each part of the exterior wall serves the purpose it performs best. There are several design variations available. I suggest you research this further, as I am also just an amateur who has done some reading. Our setup (from inside to outside) is sand-lime brick – mineral wool – brick veneer. However, brick veneers are certainly not everyone’s preference.
If you decide on a timber frame structure, use mineral wool or cellulose insulation. These add more mass, providing better soundproofing and thermal insulation at a reasonable extra cost. Otherwise, it can be difficult to fix later if you find that noisy parties in the neighbor’s yard bother you or the sun is hotter in summer than expected.
If you decide on a timber frame structure, use mineral wool or cellulose insulation. These add more mass, providing better soundproofing and thermal insulation at a reasonable extra cost. Otherwise, it can be difficult to fix later if you find that noisy parties in the neighbor’s yard bother you or the sun is hotter in summer than expected.
schroedinxer schrieb:
What would you prefer? The concrete builder also offers other options for an additional cost.Which options and at what additional cost?
S
schroedinxer24 Nov 2019 10:37face26 schrieb:
What options are available and what are the additional costs?Brick slips are unfortunately not very common here. What could be a possible alternative to brick slips for the exterior?
Regarding the additional costs, I would need to make inquiries. The scope of work description notes any choices where applicable. For the exterior wall, it states: Residential floor exterior wall 36.5 cm (14.4 inches) aerated concrete masonry (0.09 W/mK).
Additional services: Different exterior wall bricks? Extra thermal insulation on the exterior masonry?
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