Construction financing on a solid foundation?

Hello,

we are planning to build a solid house with total costs of just under 390,000 euros (cost estimate from the architect). We can contribute about 20,000 euros in labor and 60,000-70,000 euros in equity.
It will be a semi-detached house (Kfw 70, 175 sqm) with a basement and a recessed top floor and a single garage. Only the kitchen and the move are not included in the costs.
Approximately 310,000 euros in external capital is needed. (100,000 euros KfW, 210,000 euros bank).

About our situation:

He (32): 2800 net
She (32): currently 1000 net, from summer about 1600 net
2 children (1 and 3 years): 268 euros child benefit

Another child is planned in the future. That means the wife’s income will be reduced for about 1 year. Otherwise, an increase in income is expected.

Monthly rate: 1000 euros plus 400 euros additional costs (is that a realistic amount for additional costs?) Making a "warm rate" of 1400 euros per month.
2 cars, urgently needed for work

The money we save goes immediately into special repayments.

Would you go ahead with the house construction with this amount? Otherwise, we would first remove the basement. The garage can also be built later if necessary.

Interest rate, repayment, and term missing?

Two KfW loans? Then after 10 years you still owe 80,000, which must be refinanced with your bank if the other loan runs longer. You will then have to accept the bank's interest rate.

Interest rate of the bank: 2.5% for 15 years. Repayment was, I believe, 2%. I would have to check again. Planned are about €5000 per year in special repayments, especially after salary increases. We would also rather focus on paying off the Kfw loans (mischzins): 1.65% in 10 years.

Dirt... accept interest rate... the KFW offers follow-up conditions that are market-based, just like the house bank. So already two offers that compete.

20,000 EUR own contribution in saved wages? At 50 EUR/h that is about 400 hours, which corresponds to about 10 weeks of work (on vacation?), provided you are as fast as a skilled worker.

I can't quite imagine it, but at least it's not completely impossible.

Otherwise, as Koempy writes, information is missing.

Do you already have the property or is that included in the 390k Euro? Are property transfer tax, additional construction costs, etc. already considered in the above figures?

Regarding the 20k Euro personal contribution, I agree with toxic. That would already be quite a lot...

Hello, everything is included in the €390,000. That means land, additional costs, construction costs, outdoor facilities, garage, connection... €20,000 is indeed a lot but if it doesn't work out, Shi, we still have some equity left. We also have help from family and friends.