Evaluation of Construction Project / Credit Offer

On the topic of personal contribution: €30,000 at €50 saved labor costs equals 600 hours + a surcharge because you are inexperienced... You spend 75 days at 8 hours each on your shell construction. Seriously?

Your incomes are very good and surely sufficient. But whoever has a wine cellar in the five-figure range and takes vacations costing €20k per year and had an expensive wedding, etc., lives in the here and now. That’s okay, don’t get me wrong. But that won’t fit your necessary lifestyle for the next 10-15 years.

Better save €20k per year for the next 3 years, and if after that you say you haven’t missed anything in those 3 years, you’re ready for the house.

Your incomes are very good and certainly sufficient. But anyone who has a wine cellar worth five figures and has taken vacations costing 20k p.a. and had an expensive wedding etc. lives in the here and now. That’s ok, don’t get me wrong. But that will not fit your necessary lifestyle for the next 10-15 years.

Better save 20k p.a. for the next 3 years and if after that you say you didn’t miss anything in those 3 years, then you are ready for the house.

That’s exactly the crux of the matter. Anyone who maintains a relatively extravagant lifestyle will not suddenly—out of necessity—give it up just because they have to pay off a mortgage.

Hello,

thanks again for the many good comments.

@ Tassimat: 3 months in a row will of course not be possible, but I already have a rough plan in mind and have also roughly planned the respective project phases as DIY work and included some buffers.

I would approach the first phase of DIY work as follows: 3 weeks of vacation = 23 days for the ground floor, to be exact: tiling floors, painting walls, and possibly installing interior doors. If I only count the weekdays (=15 days) and work 8 hours each day, that would be 120 hours. My wife would contribute a similar number of hours here, and in addition, I can occasionally count on free help from relatives and friends.
With the completion of this work, a provisional move-in would already be possible, since we are planning a small bathroom with a shower and a guest room on the ground floor. Except for the kitchen, all furniture is already available anyway.

The second phase is similar to the first, but for the upper floor; here we are not under the same time pressure, since, among other things, the two planned children's rooms would not necessarily have to be completed immediately.

The further planned DIY work involves the creation of the outdoor area; here we personally do not see much time pressure and could imagine working on this over several years (if all else fails).

@ michert: The hours would mostly be contributed by my wife and me (so already 2 people), and in addition, we will receive some hours of free help.
Since the DIY work also includes the design of the outdoor area, the hours would not all have to be done consecutively but distributed over a longer time horizon.
Otherwise, the comment is of course correct, doing the hours all at once would definitely not be possible.

Regarding our lifestyle, we are very aware of this and have changed it radically. Waiting longer is unfortunately almost out of the question for us; on the one hand, this would significantly delay family planning (we are currently already calculating with 3 years until the topic can become concrete, then we would be 35; with another 3 years we would be 38, which is actually too old for us), on the other hand, we think that the savings accumulated by then would be lost in higher costs.

In the case of self-performance, also remember to consider or plan for the contributions to the BG + if applicable, insurance for helpers

In case of own work, also remember to consider the contributions for the BG and possibly insurance for helpers

The client is initially not insured and does not have to pay mandatory contributions.

The client is initially not insured and does not have to pay any mandatory contributions.

That is clear. Hence also my statement "possibly.. insurance" (also intended for clients themselves, since you are not insured in case of your own accident) And the BG Bau referred to the following statement by the OP:

[...] additionally we will receive some hours of free help. [...]

Maybe the OP has not yet considered this and it might be helpful for him to read up on it.