Estimating renovation costs of a single-family house from 1965

I interpret your descriptions and the drawings as indicating a probably monolithic exterior wall, so take some facade photos from all sides.

The pictures now suggest that the wall structure is somewhat two-layered, but without an air gap.

Where is the house located, the prices are too low for southern Germany and other major cities

Looks like Lower Saxony.
The numbers add up, it's still significantly cheaper than in the remote regions.
Normally it's double-shell, then you can blow something in and save on external facade insulation.
Breakthroughs shouldn't be a problem, neither the swimming pool wall nor the kitchen wall seem to bear any load as far as I can tell.
Overall, I really don't find the house bad, it has a lot of potential.
For the swimming pool room, I would also make an opening, but make it closable again with a sliding door.
You could make a cozy TV room, then in the large dining/living room you only have a nice big table and no ugly TV standing there.

Hi Leschaf,

here are my rough estimates (from various renovation calculations and offers) compared to your rough estimates:

- Electricity (still 2-wire throughout the house) (20K€?)

Fits, in my opinion even including switches and one or the other additional socket.

- Radiators (-> install underfloor heating, i.e. new screed as well) -> (?€)

Remove floor, install underfloor heating, new screed I would have estimated at 100 €/m²; in another thread recently someone said they did it for 80 €. So for you about 15 K€

- Flooring ~170m² -> would like planks (20K€?)

I would have thought cheaper. But I never got an offer for planks. Please check the combination of planks + underfloor heating. That could be tight due to wood's poor thermal conductivity. Even with parquet and underfloor heating with low flow temperature, the so-called engineered parquet is sometimes recommended, which only has about a 3 mm real wood layer.

- Interior doors (front door is OK, about 10 pieces) (5K€?)

Fits.

- 1 of 2 bathrooms (~10m²) completely, new furniture in the second bathroom (just newly tiled / sanitary installed) (15K€?)

Fits, if no frills.

- 2 openings, one potentially through a load-bearing wall (each about 10m² wall) -> ?€

Someone here did that recently:

The only thing we didn’t do ourselves: wall opening from kitchen to living room. But that was so worth it!
And including statics it was surprisingly cheap at 1700 EUR gross. The hole is 115x200 cm. Statics don’t work without a steel frame anymore but we find it perfect that way :)

- Kitchen (15K€?)

Fits, if no frills.

- Façade insulation? Currently energy class F with clinker façade, windows are consistently double-glazed and from various years. (?€)

If you want to commit architectural sins and just install ETICS with ugly white plaster, then you’ll probably get by with about 20 K€. But hopefully something remains for a nicer and lower-maintenance façade. Better budget 30 K€.

- New windows/doors towards the garden (15K€)

Fits.

- Wallpapering and painting 150m² living space (€?)

I never got an offer for that. Booked under "petty cash". Maybe the rude awakening will come eventually.

- Heating is from 2013 and still oil -> sustainable heating system (e.g. pellets for ~35K€? - enough space available)

Better a heat pump, 15 K€.

- Roof is largely uninsulated (attic was once amateurishly insulated by the owner) and still original tiles (45K€?)

Careful: You may postpone this task for max. 2 years because of the insulation obligation on ownership change. Better do it right away. Price fits.

What about the following items?
- New water pipes? (7 K€)
- New heating pipes? (5 K€)
- Moving walls?
- Basement waterproofing? External waterproofing including earthworks and perimeter insulation approx. 40–50 K€. That could be important because you might have earth-contact living spaces in the basement level. And also the street-side basement rooms are within the thermal envelope, as far as one can tell from the floor plans.

If you want to commit architectural sins and just install ETICS with ugly white plaster, you'll probably get away with around €20k. But hopefully there will be something left for a nicer and lower-maintenance facade. Better calculate €30k.

What would be a sensible solution for an existing brick facade like this? Besides the potential injection of insulation material?

What would be a sensible solution for an existing clinker facade like this? Apart from potentially blowing in insulating material?

In the object of the OP, in my opinion, there is no air gap into which anything could be blown.