ᐅ Enlarge and completely renovate a single-family home, or demolish and rebuild?

Hello everyone,

Here is the situation:

We have the opportunity to buy a plot of land (600 sqm (approximately 6458 sqft)) with a house from the 1960s that offers 105 sqm (approximately 1130 sqft) of living space over two floors for 150,000 €. The value of the land alone (land reference value) is 130,000 €.

For us, however, the house is too small. We would like to undertake the following measures (the development plan allows all of these):

1. Extend the house by 3 meters (about 10 feet) to the rear and 3 meters (about 10 feet) to the side.

2. Add extra floors.

3. Install a new roof.

4. Replace the exterior facade.

5. Complete interior refurbishment.

In other words: we basically want to redo everything.

Would this be financially worthwhile, or would demolition and rebuilding make more sense? Are there any tips regarding funding options (KfW programs) or similar?

Please excuse me, as I am (still) a complete beginner. I understand that it is impossible to predict costs here, but maybe there are people who have undertaken a similar project 🙂

I would appreciate any information.