we have already run the numbers with a bank and they would even give us a loan with a monthly payment of €2,500.00.
Do you have that in writing? Or could that be a misunderstanding?
That’s almost negligent. I can’t imagine that.
House (including kitchen and materials for walls/floors): €405,000.00
And I also consider this tight sum for “house costs” (for 140sqm?) not to be “right.” For one thing, you never include the kitchen in the house price. The kitchen is furniture and is not financed by some banks either.
The same applies to additional purchase costs.
I would first make a proper calculation out of it.
Equity will probably then be used for the kitchen, lamps, bathroom furniture etc.
Then you deduct your own work to get an overview of how many hours you have to work on the construction.
With a child and a job, it is not necessarily a given that you can do everything you think you can.
The outdoor facilities as equity are okay, but even there the budget could already become tight. You hardly have any potential to save then.
Your 13th monthly salaries are also used for other things, right?
I see the problem that everything is calculated to the limit: there is no savings rate for a replacement vehicle, then the following quotes:
We are also quite willing, for example, to no longer spend €300.00 monthly on clothing and drugstore items.
My husband and I each have a 13th salary, which would serve as an annual buffer,
… it’s not nice to save on “everything” just so you can pay a rate. Of course, owning a home is great, but with 110sqm and cold rent of €700 you are doing very well - you won’t be doing that well anymore, neither financially nor relaxed in the evenings over years.
The incidental costs include a buffer of €5,000.00 and additionally I had indicated a “free buffer” of €5,000.00. Is that way too little? What would be more appropriate?
There are usually already gaps in the construction service description that make it necessary to loosen several thousand easily: be it the electrical work or the desire for an additional window, sliding door, larger attic and thoughts about building only once. “Turnkey” means nothing nowadays; it does not mean there are no additional costs. Price guarantee also does not apply to necessary additional costs.
Whether the salary is too low or the equity insufficient is something to consider individually. In your case, I (still) don’t even read about the habit of being able to go to the limit handcraft-wise. Let me put it this way: there have already been craftsmen here who rely on their own skills and those of acquaintances. But they first have to keep their employer happy before going to their own construction site. A desk person can burn their own resources very quickly by doing unfamiliar work. In the worst case, long-term absence results. This means that your own physical performance should also be calculated modestly.
I see here rather further savings and then a young used property as a semi-detached or terraced house.