Comparison tests of various central controlled residential ventilation systems + additional questions

Then it is not a diffusion-open wall assembly! Our wall assembly in timber frame from inside to outside, clay plasterboards - OSB - stud frame with mineral wool - wood fiber insulation - plaster.....no vapor barrier or any other plastic nonsense. Considered a very good wall assembly by the independent building inspector of the Homeowners' Protection Association.

Except for the clay plaster, that is also our assembly.

A standard detail in timber construction is OSB or foil as a vapor retarder, then insulated studs and on the outside a windproof layer made of fiberboard or membrane. From inside to outside always less airtight. I also think that the assembly with OSB and fiberboard is good, but I don't really see it as diffusion-open.

All OSB joints tightly sealed with tape. The base areas and transitions to the wooden ceiling sealed, I had a somewhat "romantic" idea of timber construction before I saw how it's done.

OSB is not vapor-permeable but wood residue held together with a lot of glue.

That's how it looks, and OSB particularly molds well when in contact with moisture and poor ventilation, you can practically watch it happen. The joints and screw holes are especially susceptible.