General Contractor Construction Service Description

Ask him exactly what he means by how the air in the house is exchanged. Without a ventilation system, usually only manual ventilation remains, unless I am missing something. I'm curious how the general contractor meant that.

I'll do that but it will take a while. I won't get the offer until the end of the week. Number 2 is building with controlled residential ventilation.

I assume that Poroton with internal insulation will be used as the exterior wall, which means waterproof, airtight, and vapor diffusion open, therefore controlled residential ventilation can be omitted. If the exterior wall is constructed with other building methods including a vapor barrier, controlled residential ventilation is almost mandatory. We built with Poroton without controlled residential ventilation and are still alive. After the demolition of a house with 80 years of warm air heating, I am away from all air ducts, yuck. Regards Nida

I assume Poroton with internal insulation is used as the exterior wall, that means waterproof, airtight and vapor diffusion open, therefore controlled residential ventilation can be omitted.

No, it cannot. Vapor permeability has nothing to do with the question of controlled residential ventilation yes or no. Modern ventilation systems are sophisticated and easy to use when used properly. Without it, you constantly have to keep moisture and mold under control. Some people just prefer to occupy themselves with other things...

why then do 100-year-old houses rarely mold, the building materials were vapor diffusion open. Plattenbauten and similarly dense houses mold if more water vapor is produced (showering, bathing, living, drying laundry, etc.) than is ventilated out or diffused. After the sauna or shower we also ventilate. Regards Nida

you inform yourself so thoroughly and question everything,
you are building the perfect house,
I wish you much success

our decision was, KFW 55, without controlled residential ventilation but all insulations from the Kfw40 column