ᐅ Looking for guidance on wall construction options

Created on: 24 Nov 2019 08:39
S
schroedinxer
S
schroedinxer
24 Nov 2019 08:39
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
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-XIII-
24 Nov 2019 08:45
How is the plot situated? Are sound insulation and thermal insulation important factors for you?
S
schroedinxer
24 Nov 2019 09:03
The property is located in a general residential area. We are in noise level zone II, though this does not take into account future developments. We are several houses away from the main road.

Noise is therefore mainly an internal issue.

Thermal insulation is more of an economic consideration for us. If it makes financial sense, then we are willing to invest in it. However, if it results in a clear loss, we will not pursue it. The solid construction house, in this configuration and considering KfW support, would be about €40,000 (approximately $43,000) cheaper. Living space is approximately 210 m² (2,260 sq ft) plus 50 m² (540 sq ft) granny flat.
N
Nordlys
24 Nov 2019 09:05
Think about what happens to different types of houses in the event of water damage.
Definitely the solid construction house. Also because of its long-term value.
K.
face2624 Nov 2019 09:26
A lot of philosophy...

A lot of hocus-pocus...

Has anyone told you about diffusion and breathable walls?

From an energy perspective, you should first specify which type of Poroton is being chosen... there are huge differences.

If your focus is only on economic aspects and you don’t expect extreme energy price increases, you will have to work hard to save €40,000 while living in the house.

Typical Passive House builders are usually motivated by a desire for maximum self-sufficiency, ecological sustainability, or the expectation that energy prices will skyrocket.

Edit: I just noticed Poroton = Energy Saving Ordinance. That’s obviously comparing apples and oranges.
D
Daniel-Sp
24 Nov 2019 09:33
Hello,
there are locations where, in 20 years, the condition of the existing house will play a very minor role when determining the resale value.
For me, the quality of living is much more important, and the wall construction is less significant in that context; there are other factors to consider, which you should define for yourself and then discuss with your architect.
How far insulation remains cost-effective is hard to predict without knowing future energy prices.
Personally, I would avoid using plastic in the wall construction (just my opinion), but of course, everyone has their own view on that. I find plastic unsuitable in timber construction in any case, and it is possible to build without it.
Best regards, D.