Object evaluation – Rough outside-in evaluation possible?

I would find that outrageous. The 420k corresponds only to the land value (if even that). Such a cheeky offer goes straight into the circular file – you can save yourself the effort.

With just over 1,400 sqm of land, you have at least 800 sqm as building land. If the plots around are all larger, often 1,000-1,200 sqm are set as building land (often plot width and 40m depth as a description of the standard land value or 800 sqm as a minimum estimate). You certainly won’t get out of the valuation below 450k.

What the plot offers in terms of surplus building land must also be reasonably divisible. The property appears neglected to me here (probably in the typical form of an aging builder withdrawing to the "ground floor only") and therefore in its undeveloped status quo not to be considered a marketable object. From a commercial perspective, it seems appropriate to me that, as a net result, a value below that of the bare land can certainly emerge. For this reason alone, I would not add any goodwill to influence the decision of fate. However, the original poster (see his assessment of the attractiveness of the location) also has subjective stakes involved and therefore has to add goodwill accordingly. But I would recommend doing this moderately and weigh reason higher than the likelihood of a premium. The renovation of apparently (almost) solely cosmetic defects should not be underestimated. I suspect here a renovation delay lasting about twenty years. Maybe, even if this would not be a case for him regionally, might have an opinion on this (?)

What the property offers in terms of surplus building land must also be reasonably divisible.

That's why I am not even expecting a surplus, but "only" a normal amount, as if it were a normal (oversized? I don't know in the location) property. My own property is about 27-28m wide. The standard land value refers to a plot depth of 40m. So 1,080-1,120sqm of building land, which would have to be valued (and paid for) at the standard land value. As I said, this information from the OP is only available for a fee.

... The property seems neglected to me here (probably in the typical form of the aging builder retreating to the "ground floor only") and ...

Even though this thread is already older, the property is still listed for 750,000 EUR.

A consumption certificate is invalid if a vacancy (children's room etc.) of >30% is given. And exactly against this background, I would also view the classification of the final energy consumption of 51.1 kWh/(m²*a) for the total area. That actually cannot be...