Single-family house without a basement - generate parking space elsewhere

Or just simply enough storage rooms in the house. Sure, you naturally pay more for that - but you also need many things to be reasonably accessible.

We have an 18 sqm utility room - that sounds like a lot, but if you don't have any other storage options (and we do have garages, an outsourced workshop, pantry, storage room upstairs, large cabinets in all rooms - and we are not collectors!) and you also want it to be reasonably tidy, that's really not much!

You don't necessarily have to have a basement... A utility room on the living level is indeed a very nice thing. And a pantry by the kitchen (instead of in the basement)...

Definitely a double garage if possible, preferably 9x8m, then you can fit a lot in!!

And the first prize in the Pyrrhic victory contest. Building an almost full basement above ground doesn’t make it significantly cheaper—except maybe with rising groundwater—not even if you convince yourself it’s worth it because the car also fits inside. And it costs a lot of floor area ratio at least, if you’re even allowed to build an outbuilding of that size (sometimes 50 sqm is the limit, which I personally find appropriate—these small halls are awful).

Our house is 9 m wide. We have a roof pitched at 45 degrees and 1.2 m knee wall. The attic is exactly 4 meters wide, which results in 56 sqm of storage space. We use it as a storage room and manage quite well with the pull-down staircase. It is only used once every 6 weeks.

The climate is cold in winter and warm in summer, but never humid or very hot. By the way, our garage is also never humid. Good ventilation is the most important thing.

Thank you for your further feedback.

We deliberately decided against the basement. Since we have hydrostatic groundwater pressure, the construction would be correspondingly more expensive. Additionally, there are significantly higher incidental construction costs due to earthworks, etc. Of course, we also have to invest money to create usable space elsewhere – but overall, it is still significantly cheaper than building a basement.

We prefer to invest above ground and don’t want to scrimp on flooring, kitchen, etc., rather than build the basement and have to make compromises.

Regarding your suggestions to additionally insulate the roof:

The planned design as a cold roof means that the ceiling between the upper floor and the attic is insulated. That is, the mineral wool is applied in the attic on the ceiling with a vapor barrier foil in between.

Would it be physically possible to additionally install insulation between the rafters (Rockwool or similar)? The purpose would be to reduce temperature fluctuations between winter and summer and to increase the usability of the storage space.
I only have concerns that moisture might not be able to escape and I could have problems with mold, etc.

Has anyone of you done this – insulated attic floor plus insulation between the rafters?

My layman's knowledge: If insulation, then also heating and ventilation - otherwise there will be problems with moisture. Apparently, many people do this wrong. We were also told by the construction company that you either make a proper warm roof (tight, warm, controlled ventilation) or a proper cold roof (cold, slightly drafty, insulated only to the warm area), there is practically no middle ground.

I have no objections to insulating the attic floor from below and the roof surface, people insulate between the ground floor and the upper floor these days anyway.

Insulating and "control over the indoor climate" always go together. And an uninsulated roof doesn't create a zero difference between inside and outside either. That means ventilation is necessary even then.