Renovation of a 1960s settlement house with extension - Feedback welcome*

I don't understand. I thought it was about inventory. I'm missing the actual and the target state. I only see what is supposed to be?

I'm missing the current state and the target state.

To me, it looks pretty much identical, i.e. it seems to me that a living room was enlarged by breaking through into the garage and the bathroom was modernized in its layout (and presumably a wall was demolished where the kitchen island is now drawn), but everything else looks like contemporary 60s. And I share @dertills' skepticism that this would currently pass energy-wise.

I had overlooked that the extension is only single-story. However, the increase in dormers is also counted, since a building application is being submitted or it is a connected construction measure. Whether you stay under 50m², you have to check yourselves - and if you go over, just submit it first and see what happens.

Where is all the money going? The extension should be around €50,000. Then a new roof structure with roofing, another €70,000. And the rest for interior fittings?
The facade renovation, if it is not included yet, also adds €100-200/m². Either ETICS or ventilated with wood or brick. If you are doing everything anyway and need a new heating system, you should make sure to achieve a KfW efficiency house standard, then there are some subsidies, but the energy consultant will tell you about that.

If the result really looked similar, demolition wouldn’t be necessary, especially if what remains is still good without building sins/botch jobs. I am also more a fan of renovations (we ourselves revamped a lower 1959 bungalow last year - significantly below your renovation budget).

(we ourselves renovated the lower 1959 bungalow last year - well below your conversion sum.)

Is it in the house pictures thread?

but everything else looks like contemporary 60s.

Would you like to explain what you base that on? Apart from the wall thickness, I couldn't distinguish between poorly planned new construction and a 60s old building just by the floor plans.

Is it in the house pictures thread?

No, I wasn’t registered here yet at that time. Maybe it would have spared me some work or some solutions would have turned out differently. But now it’s too late, time will tell.
I do have a few pictures of the renovation - unfortunately far too few. When I have time (haha, good one), I will post some before-and-after pictures. In a renovated old building, where the move-in took place with only a guest bathroom and no kitchen (there was only screed and the walls plastered) and the shower was only finished two days later (fortunately), I wonder when “after” really is. When the baseboards are installed? Then you’ll have to be patient - today I was busy all day in the 2-meter-deep trench around my basement.