Financing options for a rather high-priced single-family house

As others have already written: Additional costs and children are much too highly estimated in your assessment. Reserves are often included in the "€-per-sqm additional costs" that you find online. So they also appear twice for you. Overall, you have a very solid income situation. A rate of 1,700 should not be a problem at all. And regarding your initial question about costs for teenagers: that is still a long way off for you; in the next 10-15 years there will continue to be salary increases and perhaps your wife will return to work...

Well, the concerns are settled for the time being - thanks for the input

It may be that we can look at an existing house next week. The price including the land is a flat 600,000€ including incidental costs (broker, notary, and land registry). The house is from 1965. The living area is 165 sqm over 2 full floors, plus a basement and an unconverted attic. Roof shape is a gable roof.

Now the calculations naturally begin. We would see 250,000€ as a limit for the renovation, i.e. plan with 200,000€ and have 50,000€ = 25% as a buffer - and even if the buffer is used up, we would still have about 40,000€ left to cover disasters - but that would be in well-interest-bearing investments, so rather something we do not want to touch. Is that a good approach or too cautious?

What could theoretically come up for us, we have listed here. Is that more or less complete? What is still missing?

Kitchen	20000
Bathrooms (bath + guest WC)	20000
Flooring (wooden floorboards? parquet?)	15000
Painting, plaster, and co (new plaster after new electrical work?)	15000
Electrical (house from 1965)	20000
Windows (ground floor facing the garden to open + about 15 smaller windows, partly enlargements)	30000
Architect/structural engineer (~15% of construction costs)	30000
Heating (unclear if necessary)	20000
Roof (unclear if necessary)	25000
Floor plan work (1-3 breakthroughs ground floor, potentially load-bearing walls)	20000
Garden (tear down balcony (x2), build terrace on raised ground floor with connection to garden)	20000
Floor insulation	10000

The planning already eats (almost) our entire buffer – have I perhaps estimated somewhat too high? What about replacing water pipes, for example – does that fit into the sum for heating? How does it look for the roof; I think re-roofing might possibly be needed, but new insulation probably not? Should KfW subsidies of roughly 10% of the costs be deducted?

If we are roughly right with this, we can of course better estimate the financial situation in case some things have perhaps already been done. Of course, an expert and an architect will accompany us as well.

Depends on how much you want to renovate the house. We are currently renovating a house from the 60s. For the money it costs us to bring everything up to new-build standards, we probably could have built new. If you are interested in exact numbers, I would have to look them up first. We told ourselves "if you're going to do it, do it properly," because later it will be much more complicated to do anything afterwards.

It depends on how much you want to renovate the house. We are currently renovating a house from the 60s. For the money it costs us to bring everything up to new building standards, we probably could have built new as well. If you are interested in exact figures, I would have to look them up first. We told ourselves "if we do it, we do it right," because later it gets much more complicated to do anything retroactively.

We don’t have to bring everything up to new building standards – we can’t afford that anyway. But it also can’t be that in 10 years we have to tear everything up again because the pipes don’t hold up anymore. I’m really only looking for a rough direction here; for everything else the support during the inspection is there. But maybe I forgot a category or seriously underestimated something?

Your figures would interest me a lot – the examples online are usually quite simple and often already outdated.

The planning is already eating up (almost) our entire buffer - did I perhaps budget a bit too high? What about replacing water pipes, for example - does that fit into the total for the heating system? How about the roof, I think re-roofing might possibly fit, but new insulation rather not? Should one deduct KfW grants roughly amounting to 10% of the costs?

Very generously calculated in most positions. Why do you need an architect? A structural engineer is enough. But get an energy consultant and collect 20% KfW funding for energy measures. Or make it an efficiency house and get up to 40% (energy measures + surrounding things like floors, underfloor heating, ventilation, screed) ==> with the budget that should be easily doable. Insulate the basement and the top floor ceiling yourself. Probably only costs 2-3,000€.

I am currently renovating a two-family house myself. The house will probably be KFW 55, 120sqm ground floor gutted down to the foundation walls, 80sqm upper floor only new heating + windows and ventilation (the roof is fine). I expect around €70k after KfW funding. Actually, "expect" is the wrong word, the offers are heading in this direction.

You should check the energy saving ordinance. It may be that you are obligated to insulate it anew after purchase.