Flat rate cost for house renovation - what is realistic?

Hello dear forum,

we are currently trying to purchase a house from the 1950s. As far as we could assess during a first inspection, almost everything needs to be renewed: roof, electrical system, windows, moisture in the basement, etc. In the 2000s, the heating was already converted from oil to gas.

We received information from the architect that for a renovation and possibly an extension/remodeling, an average flat rate cost of 3000 EUR per sqm has to be calculated (work carried out by companies, no DIY). Is that realistic?

If so, why bother bringing such an old house up to standard at all and not just tear it down? Or perhaps even refrain from buying altogether and look for a building plot? Because then I would be paying for land + old house + renovation, instead of just land + new construction...

Our first step is to better estimate the total effort and determine the necessary financing requirement. What are your assessments/experiences/recommendations on this?

Thank you very much and best regards

We received information from the architect that for a renovation and possibly an extension/conversion, an average flat rate of 3000 EUR per sqm must be budgeted (work carried out by companies, no own contribution). Is that realistic?

For 3,000€ I would rather tear down the house and build a new one. There's probably a plot + new building for that as well. I consider the architect's price completely exaggerated, unless he wants to renovate to Kfw 40 standard with high-quality equipment.

...thanks, we asked ourselves that too, i.e. if that were common, then no one would renovate an old house. He has already oriented himself somewhat towards kfw, since the reference to funding also came up. Among other things, the replacement of a gas heating system with pellets was also mentioned in this context. But even here we wonder whether that would be necessary at all, since the heating system from the 2000s was only recently converted from oil to gas. So a gas connection would be there... Is there a kind of "rough estimate" per sqm that one could use for a calculation? I know there are certainly no limits upwards, but it would be interesting to know how much you can roughly assume if you do not necessarily orient everything towards the highest kfw standard and taking advantage of these subsidies.

Is there a kind of "rough estimate" per sqm that one could use for a reasonable calculation?

Is there some kind of "rough estimate" per sqm that one could use for a calculation?

Sort of. It depends on what you mean by "renovation." Partial renewal and partial beautification? Comprehensive renovation (of what?)? Core renovation down to the foundation walls? KfW energy standard aimed for? With €1,500 per sqm you get a well livable house. I am currently renovating a 200 sqm two-family house to a KfW-55 house. 120 sqm apartment EVERYTHING new. 80 sqm apartment with new windows, completely new heating (heat pump with new radiators). Roof and basement do not need to be touched. With own work, I end up at €550/sqm; with craftsmen about twice as high. However, 40% of the energy-related costs are reimbursed by the KfW. For me, that's about €125/sqm.

We also faced the decision to renovate and expand a house from the 50s (with good structural condition without moisture) or to demolish and rebuild. Various architects told us that a renovation (i.e., everything new, including insulation, roof, windows, heating, plumbing, and electrical) would be about 20% cheaper compared to a new build of the same size -- but there would be many restrictions regarding the layout of the house, etc. We ultimately decided on the new build.

Our first idea would actually be both, i.e. renovating and beautifying / expanding. To gain a bit more space, we also thought of extending the living room with a small annex, about 28 sqm.