Prefabricated house - wall structure

Are you concerned about ecological materials? You won't be very happy with timber frame constructions either if you look at how these things are produced.

High-quality materials were important to us as well, but at some point we had to draw the line:

From outside to inside:
- Silicon resin plaster
- Wood fiber insulation board
- Timber frame with cellulose insulation
- OSB board with vapor barrier
- Installation level with rock wool insulation: This could have also been done with cellulose insulation, but it's difficult with DIY work that has to reach the installation level because this insulation has to be blown in.
- Fermacell board

Personally, I find the effort very good and it was already standard for us with a 31 cm thick wall. Most others simply add another layer on top of the installation level if desired, but then you lose living space again.

At the end of the day, the wallet decides. A good timber frame construction starts at 1500, so contrary to popular belief, it is not cheaper than solid construction. However, there are worlds of difference in terms of energy efficiency. Point 1. Use your brain: someone who offers 1100 cannot have the same as someone for 1500. Even if it sounds tempting. Comparing that is difficult even for professionals. Years ago, there was a manufacturer who only pointed out in the fine print that VAT (at that time 15%) was added to all prices.
Wall structure next to the installation layer: I always prefer the ventilated facade (also with plaster), if it really can’t be done otherwise, then also with wood fiber. Never that Styrofoam stuff.
Choose heavy insulation materials, good for summer heat protection.
Oh, the list is already quite long. Don’t rush anything. Look at it calmly and think it through. Ask again if necessary.
Regarding the installation layer: if I’m going to do eco, then also in the installation layer, whether with hemp or wood fiber, hardcore fans with flax.
And you don’t lose any space through an installation layer, that’s what distinguishes the good from the really good.

An insulation layer is state of the art today in good timber frame construction, without additional cost.

So far, apart from the one we used for our current build, I have not found any manufacturer (not even the big ones) that offers this as standard. It always comes with the next wall thickness.

So far, except for the one we have just built with, I haven’t found any manufacturer (not even the big ones) that offers this as a standard. It’s always with the next wall thickness.

There are quite a few of those. The problem is, this market was left to the prefab house manufacturers (i.e. the big ones) until a few years ago. But they have partly stayed stuck in the 70s in their development. Today, they just stick a bit more Styrofoam on. I'll say it clearly: every good Scandinavian has been building with the installation level for well over 10 years, even at a time when people here didn’t even know how to spell that.....

In our wooden house (not a "prefabricated house") it is from inside to outside: glued laminated wood panel as interior cladding (instead of drywall), battens, installation layer filled with soft wood fiber insulation boards, OSB board as vapor barrier, timber frame with cellulose insulation (Isofloc), hard wood fiber insulation boards, battens/ventilation gap, wooden facade.

Are you concerned about ecological materials? You won't be too happy even with timber frame trades when you look at how these things are produced.

High-quality materials were important to us as well, but we also had to draw the line somewhere:

From outside to inside:
- Silicone resin plaster
- Wood fiber insulation board
- Timber frame with cellulose insulation
- OSB board with vapor retarder
- Installation layer with rock wool insulation: This could also have been done with cellulose insulation, but that's difficult with DIY work that needs to reach the installation layer because it has to be blown in.
- Fermacell board

I personally find the effort very good and this was already standard for us with a 31cm thick wall. Most others just add another layer if the installation layer is desired, but then you lose living space again.

Thanks for the answer. No, the ecological aspect is not the primary concern. Rather, high quality, so that in 20 years there is good insulation and indoor climate. Thank you also for the build-up! Is there a construction diary for your house? Or how could one find out who you built with?