House construction: Dream of a house affordable?

Good evening!

I'll keep it short and sweet... we would like your assessment of our situation. Can we afford a single-family house?

He: €3200 net including company car (already considered)
She: €866 (Parental allowance Plus + child benefit) -> child is 6 months old; planned part-time (€1319) from kindergarten
Total: €4066

My current Excel calculation says that we could currently manage a rate of €1200 + €500 operating costs.
Are the operating costs appropriate? I included insurance, ancillary costs, reserves.
Our current savings rate is €830/month, which would drop to €580 with my assumed rate.

Equity: €111,000

Own contribution:
- Electrical + network (I work at an electrical company) except for things that have to be done by a master electrician;
- Installation of doors/windows/roller shutters, etc. (My wife works at a related company; possibly a discount on prices -> not certain -> therefore not calculated)

What can be credited as own contribution (in €)?

We had a rough estimate made by a known civil engineer for a plot of land that is for sale.

Land costs:
- €113,760 plot 632m² at €160-180
- €1,707 notary fee 1.5%
- €3,982 acquisition tax 3.5% (Bavaria -> Lower Franconia directly on the Hessian border)
Total: €119,449

House construction costs:
- €270,000 house 150m² at €1,800 (medium standard; ground floor + upper floor)
- €20,000 double garage (possibly only one, but with a "shed"?!)
- €50,000 incidental construction costs
- €20,000 outdoor facilities
- €50,000 basement (in the houses left and right of the plot, the basement is half in the hill; basement plan towards the street side...on the hill side you enter the garden directly on the ground floor)
- €7,000 house connections
- €6,000 building application; statics; thermal insulation calculation (Energy Saving Ordinance)
- €2,500 reinforcement plans and partial work plan
Total: €410,000

Total costs: €410,000 + €119,449 = €529,449.00

So now it's your turn... is this doable?

Thank you in advance for your assessments!

There are plenty of financial professionals here. I am not one of them. I assume that some will say, what ifs and could haves, [bicycle chain]. Numbers are one thing, a healthy own assessment of them is another. If you believe you can manage it, do it. If you think, oh no we can't do this, then don't. My father (whom I actually do not appreciate) always said, Don't plan with money you don't have.

Your model calculation will be (barely) affordable. The problem will rather be that a house plus basement for 320,000 will hardly be feasible. Even 50,000 incidental construction costs can quickly be used up just for the hole in the ground on a slope if things go badly. First, have a realistic offer made somewhere.

The desired rate is definitely achievable. We have the same with almost the same income, also a company car and just a bit more equity. However, we built much cheaper and therefore only had to take out a 220k loan. With a rate of 1200 euros, that is paid off quite quickly. Since you would need almost double the loan, that would be a bit too risky for me personally. We built without a basement and it has already been almost 5 years since we built. Nowadays it’s no longer that cheap, that’s for sure. We will be done paying off in just about 11 years and without any interest risk. We are now in our mid to late 30s. How about you age-wise? Do you still have enough time until retirement?

It is feasible, however, out of €4,500 (part-time) €1,700 goes to the house without significant repayment. I would increase the repayment.

Your model calculation will be (barely) affordable. The problem will rather be that a house plus basement for 320,000 will hardly be realizable. Even 50,000 incidental construction costs can quickly be spent just for the hole in the ground on a slope, if things go badly. First, get a realistic offer made somewhere.

Does that mean... having an architect draw the house and then checking with the necessary companies? Or have it drawn and get an estimate from the architect?

How about the basement? If I have picked up correctly here in the forum, then a construction project on this plot without a basement makes little or no sense, since the earthworks are going to be done anyway. Is that correct?