Wow, so many responses! First of all, thank you for all your hints. I'll try to address all the open questions in one post.
One thing might still be important for evaluating the whole project concerning our expectations for our own house. We are quite adaptable when it comes to compromises, e.g. in equipment (electrical, network, bathroom, etc.). The number one priority for us is clearly to have our own four walls, not which door handle set is used, whether the ceramics are from Villeroy & Boch, or if I can enjoy full luxury e.g. with the electrical installation. Although we have a relatively high equity of 200K, for various reasons we want and need to keep the loan installment as low as possible, and for that we are ready without qualms to be satisfied with simple equipment and also make certain concessions.
Surveyor ("house surveying costs") is listed in the additional costs, but only with 830 EUR. Unrealistic? 3 AFDDs are also included with 1760 EUR. Meter cabinet and installation are also in the additional costs ("construction power and electrical meter cabinet + electrician costs") and are estimated at 3450 EUR. I have a master electrician friend at hand... I just noticed that the ring earth conductor is not mentioned anywhere in the offer... Plastic gutter is also rather "meh" for me and would be replaced by something decent, if there is still money left. A heat pump is unfortunately too expensive for us to purchase, even if it is probably smart in terms of heating costs in the long run. Although on the other hand, I probably won't live long enough to see the heat pump pay for itself.
The interior of the house is not plastered at all, not even Q1. A friend who is a drywall installer would do that with us on the side. We would get materials at purchase price through his employer, so quite good stuff like Uniflott etc. He says if it's done cleanly, Q1 is enough for wallpapering. I can't judge. If I don’t see the joint edges of the drywall panels through the wallpaper afterwards, I’d be satisfied.
The 10K for the outdoor facilities only includes things like garden fence or paving the driveway. I’d sow the lawn myself, I have the patience. Flower beds and all that stuff will be done little by little by my wife. The earthworks are included in the additional costs, although the item "house connections, earthworks and multi-utility connections" with 11,000 EUR seems very cheap to me and also a bit dubious because earthworks depend crucially on the soil class, so you cannot really estimate it so flatly. However, another friend of ours owns a small civil engineering company, so we would definitely get a discount. The plot of land we have in mind is actually flat.
I hadn’t considered inspection shafts, noted. Who decides where they go and whether and how many shafts are needed? Connection for rain gutters is, according to DW, prepared during the construction of the shell and supposedly included in the price... I can’t judge that either. Disposal costs – no idea without soil class. The plot is relatively large with 1100 m2; temporary storage would definitely be possible, and disposal... perhaps spreading on the property *cough*? Depends on the excavation. Otherwise, I have calculated: 2K for filler/painting, 2K for the interior doors (there are only four), for the 50 m2 floor covering (kitchen, bathroom and hallway would already be tiled by DW) up to max 50 EUR/m2. If possible, less. Tiles would be great, especially because of the underfloor heating. Under no circumstances do we want laminate or click vinyl or even carpet; rather a decent PVC floor suitable for underfloor heating with usage class 31/32 or so.
Plot is in prospect, private sale from an acquaintance, without a broker. 1100 m2 fully developed (water, sewer, electricity), but no gas line. It’s a small town in the countryside. Since it’s not yet finalized and we still want to check building costs, I have not yet commissioned a soil survey. But that would be done before the purchase.
The blinds would actually have electric drive, at least in the living room. The rest would be operated by crank, but since all other rooms each only have one window, I wouldn’t find that tragic. I still operate the blinds with the strap since I was born – I consider the crank already an improvement over the strap, which breaks frequently. Personally, I would also rather not choose a bungalow, at least because of the required footprint, but my wife has limited mobility – so it should definitely be as barrier-free as possible. Stairs wouldn’t be so good, so multi-storey houses are ruled out. So, she doesn’t need a wheelchair, but climbing stairs is just not great in the long run.
I live in the greater Erlangen area (Franconia) towards Franconian Switzerland. I’ll look for the bungalow from Nordlys now.
One more time
Well, that’s exactly the point. Is the seller reliable or not? How should one know? What he has done before? No idea, I’ve never seen the man before. I have considered joining the Bauherren-Schutzbund and have everything I have to sign checked there legally and technically beforehand. That’s probably another 2-3K, but better than seriously getting burned... As I wrote at the beginning, we are willing to put up with a lot and also make concessions as long as at the end our own four walls are waiting – as long as I know beforehand what to expect, especially financially.
Regards