Cost of renovation?

How do you get to €2500 for a bathroom? Maybe with the cheapest products available at [Praktiker], but I doubt that too.

well, what he certainly didn't calculate are things like tools and tile adhesive etc.... that also costs quite a bit.

For example. I needed about €500 for "Nebenkosten" for my bathroom. Tile adhesive, grout, silicone, Ytong, mortar, Wediplatten...

Lamps, cables,....... Small amounts quickly add up everywhere and then add up to a considerable sum.

How is the electrical installation supposed to be done?
Should it also be redone?
But it will be difficult to do that one after the other.

And then the money is enough?
How big is your roof, should it also be newly covered or insulated from the inside?
So with the heating, it will be a complete new system?

I have something similar planned, roof 130 sqm external insulation and new covering about €25,000; new gas condensing boiler with 800l stratified storage tank and water-bearing pellet stove in the living room, new pipes and radiators another €18,000. You will quickly reach the limit with €35,000. You also want to plaster all rooms anew, renew floors and the windows are not cheap either.
With your project, you should definitely take a look at the KfW funding and grant options, something can be done there.

We need about €110,000 for roof, heating, water-sewage, electrical, house and basement door and 8 basement windows.
Electrical work is done ourselves as well as all chiseling work for supply and disposal lines, likewise the refurbishment of the floors.

I would have concerns about your project that you won't get far, alone a pellet heating system with buffer storage and circulation pump (which you definitely should have) costs about €10,000 without accessories and installation!

So the roof tiles are all fine for the most part, insulation will only be done from the inside with a floor area of 8x8m (which is a bit more on the roof due to the spraying) -> €3,000 is roughly the cost I got from my parents' roof... A new heating system (including heat storage and water storage as well as pellet boiler) 18Kw costs €12,000 with small parts and we will do the installation ourselves. The work for gutting and digging around costs nothing since no company will be hired and no load-bearing walls will be removed or beams replaced (although the latter is not yet certain -> I don’t know the cost for the container right now). For the underfloor heating, I found a package for all rooms (approx. 120 m² both floors together) from the company Viessmann for about €3,000 including insulation, foil flange, and the heating system itself (staple system) + €200 for the control modules + (approx. €2,500 ??) for the heated screed in all rooms. There are 4 windows downstairs (1x bathroom, 1x kitchen, 2x living room where 1x living room window has already been replaced) cost at Fensterversand.com is €314 per window which makes about €900 for all the windows. The front door costs approx. €800 as I saw at Hornbach and I can buy the room doors gradually as I renovate each room... What’s important to me is that it is dry, sealed and warm first, I’m not in a hurry to move in since I currently live rent-free and can thus save money to be able to do everything. I wanted to start with the bathroom (simple tiles suitable for underfloor heating, regular bathtub/toilet/sink at 11-12m² and the kitchen will be the same, no need for a €20,000 kitchen, currently a €900 Ikea kitchen without appliances was fine).