Financing new construction project with average income

We will build. So why am I writing here and asking for your opinions when the project is already decided? I have read a lot lately, also here in the forum. Every post helps me better understand what it means to build and take on monthly burdens for a lifelong dream that demands a lot.
I am curious about your opinions on our project and am sure that you will find some points that would be a deal-breaker for you (e.g., desire for children, remaining debt, etc.).
Certainly, many other people with our income will also consider whether and how such a project is feasible, as is currently visible in other threads. For everyone who is not as far along as we are, we hope to provide another point of comparison with this thread and also collect a few pieces of feedback on the planned project for ourselves.

General information about you:

[*]How old are you? 28 & 29 years
[*]Do you have children? no
[*]Are children planned? Yes
[*]What do you do for work? Public service, social affairs project management
[*]Are you employed? Yes
[*]How many hours do you work? 39 & 39

Income and asset situation:

[*]What are your (net) incomes? €2,340, €2,430. Total: €4,770 + (additional benefits approx. €3,000 per year)
[*]How much equity do you have? €135,000 + land €70,000
[*]How much equity do you want to put into the house project? €97,000

Housing costs:

[*]Current rent including utilities: €800
[*]Electricity: €48
[*]Telephone, internet, mobile phone: €60

Mobility costs: Currently 1 car, after moving into the house 2 cars

[*]Insurance: €57 (after moving into the house approx. €100)
[*]Taxes: €14 (after moving into the house approx. €22)
[*]Fuel: €200 (after moving into the house approx. €550)
[*]Repairs: €85 (after moving in €125)

Insurance costs:

[*]Liability insurance: €7.66
[*]Capital or term life insurance: €60
[*]Household contents insurance: €12
[*]Legal protection insurance: €15.41

Living expenses:

[*]Groceries: €300
[*]Restaurant costs: €20
[*]Personal care/drugstore: €50
[*]Clothing: €200

Savings:

[*]€1,500 house
[*]€300 reserves (broken washing machine etc.)

Other expenses:

[*]Media: €60 (GEZ, Netflix, etc.)
[*](Vacation: approx. €2,500 per year, not included, paid via bonus)

Income and expense totals:

[*]Total income: €4,770
[*]Total expenses: €3,790
[*]Balance: +€980
[*]Of which rent and dispensable savings: €2,300

General information about the property:

[*]How large is the plot? 650 sqm
[*]What is the land value? approx. €100 per sqm
[*]Planned new build
[*]Garages? 2x
[*]How large is the house? 132 sqm usable area

Construction or purchase costs:

[*]Land costs: €70,000 already paid in equity
[*]Development costs: paid
[*]Acquisition incidental costs: paid
[*]Construction or purchase costs: €425,000 incl. earthworks/drainage, solid construction, 2 full floors, one with waterproof tank due to hillside house, air-to-water heat pump, controlled residential ventilation
[*]Additional construction costs: €24,400
[*]Outdoor area: €38,000 (own work)
[*]Lift system: €5,000
[*]Photovoltaics: €14,000
[*]Garages: €35,000 (2 prefabricated garages stacked for hillside stabilization, one for car, one as storage/workshop/tool shed)
[*]Financing costs: approx. €1,000
[*]Buffer in loan: €15,000
[*]Total costs: €612,400

Other costs:

[*]Kitchen costs: €18,000
[*]Furniture, lamps, decorations: €4,000

Cost summary:

[*]Total costs: €634,400
[*]Deductible equity: €97,000
[*]Financing amount: €482,400

Necessary loan details:

[*]Loan amount: €480,000
[*]Type of loan: annuity loan
[*]Interest rate: 1.74% p.a. nominal
[*]Fixed interest period: 30 years
[*]Remaining debt at end of fixed interest: approx. €100,000
[*]Imagined total term until full repayment: 36 years
[*]Initial repayment rate: 2%
[*]Monthly installment: €1,500
[*]Prepayments possible: annually 10%
[*]Repayment rate changes possible? 3 times from 1% to 5%

What else is important to know?
For us, it is very important that we can repay the remaining debt after 30 years with an apartment (sale) that will have been transferred by then, which has so far served as an investment in the family. Without this security, the long calculated term would be too high and the 2% repayment too uncertain for us.
Child(ren) are planned; we are aware it will naturally become tighter then – but in the end, it will be manageable. How tight it will get is probably 100% foreseeable when the situation arises — no matter how often I recalculate salaries, add child benefits, etc. On paper, it is doable, at least for our living conditions.

I am looking forward to the feedback and comments!

All easy. Long fixed interest period and low repayment I find good - the rate does not change, the salary will look different in 30 years than today.

And the mini residual debt doesn't matter either. Costs only a fraction of the salary / pension in 30 years.

Yeah, looks good at first glance. The good equity compensates for the somewhat low income and you are still relatively young. The risk factors lie in the cost items. 38k own contribution for the outdoor area on the slope? You are definitely taking on quite a challenge. Overall, though, a healthy project, obviously there would also be support from the family in case of emergency.

Yeah, it looks pretty good at first. The good equity compensates for the somewhat low income, and you’re still relatively young.
The risk factors lie in the cost items.
38k own contribution for the outdoor area on the slope? You’re taking on quite a bit there.
Overall, though, a healthy project; obviously there would also be support from the family in case of emergency.

Thanks for the feedback.

Regarding the slope, I completely forgot to write anything or rather to sugarcoat it :)
We only have a kind of "step" on the property. So, a strip about five meters wide and around 16 meters across the property needs to be filled in front of the house.
The house then basically forms the link between street level and garden level. The garden then has about a 3-5% slope. We already have plans for this made by a landscape architect. Clearly, there’s a lot ahead of us; important retaining walls and the garages as supporting elements are already included in external contracts based on corresponding offers. What really remains for us is just the garden; the parking spaces and the area between the house and the street are already laid out except for paving/graveling. Splash protection, entrance platform, etc. still need to be done, of course.

Yeah, looks good at first. The solid equity compensates for the somewhat low income …

Yeah, it's basically just above the poverty line here in the parallel universe. :)

I am also shocked at what is now considered a low income here in the forum. After my apprenticeship, I started with 1500 net and was the king back then (15 years ago). With almost 2.5k net, you are definitely not a "low" earner :/

Well, regarding OP, I also think everything is quite okay so far. So you are building a living floor into the slope? So no basement? Then the calculation looks good. 132 sqm of living space with a basement I would not find feasible with that money. Otherwise, go for it!