Decision support for wall construction

Dear forum community,

For some time now we have been silent readers and are now about to finalize the construction contract. The land was notarized last week.

Currently, there is still one offer each for a solid house and a prefabricated house in the running, and now we face the difficult choice regarding the wall structure and construction method:

(From outside to inside)

Prefabricated house (well above Kfw 40+, close to passive): 5 mm top plaster, 100 mm ETICS (polystyrene), 12.5 mm Fermacell, 160 mm timber frame with thermal insulation, 0.2 mm vapor barrier, 12.5 mm Fermacell, 80 mm timber frame with thermal insulation, 12.5 mm Fermacell.

Solid house (Energy Saving Ordinance): exterior plaster, 36.5 cm aerated concrete, interior plaster

Now my two questions:
Which construction method would you prefer and for what reasons?
Is double paneling with 2 x 12.5 mm Fermacell on all interior sides of the prefabricated house walls worthwhile?

The construction blog is currently being prepared. We look forward to sharing our building experience and thus giving something back as previously silent readers.

Best regards
Family Schroedinxer

Where is the property located? Do soundproofing and thermal insulation matter to you?

The property is located in a general residential area. We are in noise level zone II. However, this does not take into account the future development. We are several houses away from the main road.

Noise therefore plays a rather internal role.

Thermal insulation is more of an economic issue for us. If it is profitable, then gladly. But if it is a clear loss, then not. The solid house in this configuration and taking KfW into account would be about €40,000 cheaper. Living space about 210 m² + 50 m²ELW.

Think about what happens with which house in the event of water damage. Definitely the [Massivhaus]. Also because of value retention. K.

A lot of philosophy...

A lot of hocus pocus...

Has anyone told you anything about diffusion and breathing walls?

Energetically, you should first explain what kind of Poroton is being chosen... there are huge differences there too.

If there are only economic aspects and you don’t expect exorbitant energy price increases, you will have to make an effort to save €40,000 again while living in there.

The typical Passive House builders are motivated more by the desire for as much self-sufficiency as possible, ecological sustainable ideas, or the expectations that energy prices will explode.

Edit: I just noticed Poroton = Energy Saving Ordinance. That is of course very much like comparing apples and oranges.

Hi,
there are situations where, in 20 years, the existing building will play an absolutely minor role in determining the resale value.
For me, the living quality is much more important, and here the wall construction plays a minor role; there are other aspects, and you should define those for yourself and then implement them with your architect.
Up to which level of insulation is economical can only be speculated without knowledge of future energy prices.
However, I would avoid plastic in the wall construction (a personal feeling), but everyone sees that differently. I find plastic in timber construction inappropriate anyway, and it can be done without it.
Regards, D.