Duplex 7x12m with additional room on the ground floor

10x60 divided by 2 equals 10x30... it doesn't really get any wider

I was talking about the entire plot, including the friends' half of 10x60m as well. You divide it crosswise instead of lengthwise, and suddenly houses of more comfortable width fit in. Or are the friends happy with the idea of living on such a squeezed width?

but semi-detached houses are really a crutch,

Not semi-detached houses as such, but only those with the "towel" or even "bowling alley" layout. The idea of pushing two houses together so that with the same house width everyone can double the setback on the free side can be charmingly convincing in individual cases.

The main difference is whether you - as in "peace times" - have a whole plot per semi-detached house; or whether - as is currently very much "in trend" - plots of only minimally generous width are divided into half plots.

The idea of pushing two houses together and then, with the same house width, everyone can double the setback on the free side, can be convincingly charming in individual cases.

That’s exactly the second snag that plays a role here: plots with 14m width (or accordingly 20m for semi-detached houses) or similar nonsense. I increasingly wonder what the children will say one day when they see all these cramped shacks? Reminds me of the thread with the absurd development plans – what was it called again?

The children might possibly be happy to inherit a house at all... If it is in an area where they want to live, otherwise just sell it.

Reminds me of the thread with the absurd development plans - what was it called again?

I can't quite remember which one you mean (?)

The one with the aerial shots of settlements with tiny plots and built up close together. Satellite towns. Various examples - it was creepy.

The one with the aerial shots of settlements with tiny plots and buildings close together.

Oh, by the way: