House Construction Pre-Planning - Realistic Feasibility Assessment

Yes, the property counts as equity. The value of the future property (on which you give the mortgage to the financing bank) includes the land, accordingly the loan amount is proportionally lower and thus the interest rate as well.

I don’t know the prices up there with you, but 400k can be tight, of course it depends heavily on the size of the house. There won’t be much luxury in it. The "additional costs" consume a lot on the side. Just the outdoor facilities can quickly eat up 50k if you include some paving, fences, and possibly required tree plantings and infiltration shafts. The connection costs for electricity, water, and sewage also approach five figures, then the restoration of the sidewalk/road after the construction, etc. Be careful if it’s a new development area, development costs!

In general, 20 years is the minimum. Realistically, you can calculate with 30 years if the age still fits. You should rather expect around 2k monthly so that you actually pay down something. That’s possible in a pinch with 3900 net on one salary; with a family and own home you spend less on entertainment; experience after 10 years of condominium and now house construction shows ;-)

General recommendation: Get your OWN site manager who occasionally supervises the construction site even if the prefabricated house company gives many reasons why that’s not necessary. It costs several thousand but the site manager of the prefabricated house company is employed there while yours acts only in your interest. In case of doubt, the house company quickly closes the wall before you see the botch... And you don’t have the knowledge to see what is standard compliant and what is not.

Have fun and good nerves ;-)

I don't know the prices up there with you, but 400k might be tight, of course it depends heavily on the size of the house. There won't be much luxury in it.

They are cheaper than elsewhere, see other posts. Five years ago we only had 20,500 additional construction costs... flat land without rock and floods...

The property counts as equity only if it is unencumbered. If there is a mortgage on it that has not been discharged, then there are disadvantages.

We are aware that the additional costs can quickly become quite high. It is not a new development area, but half of my mother's property. The houses there were all built in the 1950s. All flat land on a hill with no risk of flooding. According to my mother, there are no restrictions on this building plot. But that would probably need to be clarified once more definitively. Connections run up to my mother's house and would then of course need to be extended accordingly.

What that costs would of course need to be inquired about.
I find €2000 already quite a lot, even with €3900. Sure, that increases accordingly while the installment remains the same, but other living expenses also rise year by year.

We are also somewhat hoping that my mother can look after our children in 5/6 years when she retires. That way, the time could be kept quite short with just one salary plus parental allowance. But one should not plan with such speculations, rather approach the financing conservatively.

There is no land charge on the property. Accordingly, it can then be used as equity.

Does the land belong to you or to the mother?

She gave it to me at the beginning of this year, so transferred it. So it belongs to me alone.