Buying a house without a mortgage loan

The expert has contacted me and I have now told him that I first need to reach the seller again and then I will get back to him. I am now waiting for a response, as the lady does not give out her phone number. If nothing comes of it, we are out.

Regarding the gas heating: when I looked, I always only read amounts of 50k, so I estimated it that high.

You say the roof is new. What exactly does that mean? You have certainly dealt with the issue of mandatory renovation. Does the roof meet today's requirements? What about the insulation of the water pipes? The gas boiler needs to be replaced. What do you estimate the costs will be?

There is no mandatory renovation! The only thing that has to be done is what the chimney sweep checks. That means the gas boiler, which starts at 1500.--.

As mentioned, the gas boiler is from 2008 and has just been inspected again by the [Schornsteinfeger].

There is no obligation for renovation! The only thing that has to be done is what the chimney sweep inspects. That means the gas boiler, and that starts at 1500.--.

Sorry, dear . There are three renovation obligations that may arise according to the Building Energy Act - but do not have to. Therefore, here is a hardcopy (I'm too lazy to write it myself):

One should just be aware that every euro you invest in such a passion project is afterwards only worth 10 cents. So it only works if you can do a lot, a whole lot yourself. Whether the previous owner really did a proper job or if it's just lousy work is hard to judge from the outside. The draft stopper at the front door is already a bad sign. The vinyl flooring under the sink also speaks for itself. With the hole in the chimney, they probably also saved on a proper passage. And the electrical work also looks like they just used whatever was available. You yourself can often live with such "botched" work at first. But you are supposed to pay for it. When I think about how often we ourselves, even with a finished new build, are at the hardware store, I don’t know how anyone is supposed to manage a renovation without a driver’s license and a vehicle on a tight budget. The house itself seems to have 85m² of living space. If you then subtract the unusable areas for heating, house connections, etc., you're not really improving compared to your previous apartment, are you?

The 3 mentioned mandatory renovations really won’t financially ruin you now.
In short, the heating system must not be over 30 years old, there must be no uninsulated, heat-carrying pipes in cold rooms, and the roof must be insulated if there is not yet 4 cm of insulation under the roof.
These are things you can easily do yourself without it being called botched work, except for the heating system.

Of course, the structural condition can be better assessed by the expert. If the seller rejects that, I would also back away from the idea. I would write to the woman again. Maybe she just forgot. Or did she react snappishly to the request?
Maybe she suspects that you want to come with someone who will overanalyze everything and give you a reason to bargain the price down, which she is not interested in?
Write to her again that you have serious purchase interest at her stated price, and that the inspection with an expert is only for your assurance that the structural condition of the building is okay. And that you have no nasty intentions there. I would try again; it can’t hurt.
Best regards, Kati