Planning a semi-detached house? Costs of a semi-detached house compared to a single-family house? Experiences?

First of all, thank you for the information! Apparently, I have always thought too complicated :-)

The land from the municipality is reasonably priced. I expect about 300 €/sqm. The problem is obtaining the plots. Currently, there are around 450 interested parties for about 40 building plots, 20 of which are municipally owned, the others are already in private hands.
It’s not much different in other municipalities. There will probably be an allocation based on a points system. It likely depends on whether you live in the town and whether you also lived there 10 years ago. And of course children, clubs, workplace, etc. For the 20 building plots, there are 90 interested parties living in the town. We do live in the town but moved here later. So it’s like playing the lottery.
The building plots that are privately owned can of course be bought. With 400 interested parties, you probably end up meeting in the community hall to bid... I’m exaggerating a bit. But I expect rather 400-500 euros/sqm.

I have done some research regarding the building regulations. Roofs with a 10° slope must have green roofing (FD and PD). This is the case for about 3/4 of the building plots.
Also great, I am not a fan of green roofing at all => Do you have any experience with green roofing?

About our current situation: We rent a semi-detached house, 100 sqm, cellar, built in 2015, KFW55 on a 460 sqm plot. This has to be topped :-) And that makes it difficult. You can tell that purchase/build costs have completely decoupled from rental costs. Just for the land, I could already rent for 10 years...

The comfort issue of a single-family house remains. But that is gone if I have no terrace, no garden, no garage for the first 5 years, just a pile of dirt where weeds grow. Sorry, it is very frustrating. :-(

What do you have against green roofs?
They are cool, eco-friendly, and look great (ok, you rarely see a [FD] from below)... of course, it has to be done professionally, obviously.
We are greening our garage completely voluntarily ;) and if we had to have a [FD], it would be greened as well.
The 1-2 times a year you have to pull out tree seedlings is still a manageable amount of work.

Regarding our current situation: We rent a semi-detached house, 100 sqm, basement, built in 2015, KFW55 on a 460 sqm plot. That’s the benchmark to beat :) And that makes it difficult. You can tell that purchase/construction costs have completely detached from rental costs. Just for the land, I could already live renting for 10 years...

How much do you pay in rent? Since a house is only relevant relative to retirement planning, it might not make sense for you at all, since you already have a large garden. Maybe you are doing well with renting?

Otherwise, I recommend a used property where carport and garden are already available. The costs are usually more manageable and living there is more charming :)

I see hardly any advantages of a new building compared to the rental relationship. If the money is not enough for a single-family house, I would leave it.

What do you have against green roofs? It's cool, eco-friendly, visually great (ok, you rarely see a FD from below)... of course it has to be done professionally, logically. We green our garage completely voluntarily ;) and if we had to have an FD, that would be greened as well. The 1-2 times a year that you have to pull up tree seedlings is still manageable work.

Our flat roof is also greened, I think it's great and above all protects the sealing from UV radiation

Have an extensive green roof on the garage. Absolutely low-maintenance. Was last on the garage 1.5 years ago.