Construction cost estimation of a semi-detached house experiences

Dear house construction forum,

I have already read some threads and researched a lot on the internet. However, the statements regarding the construction costs for a semi-detached house vary greatly. Therefore, I have created a meaningful calculation and would like to know whether this can be considered realistic.

Basics: Family with one child, construction of a semi-detached house on a base plate, approx. 140m², KFW40 standard without QNG, planning with architect, brick facing, gable roof, terrace expansion, large garage for one car and 1-2 bicycles and storage rooms, heat pump or local heating, photovoltaic system, possibly necessary central ventilation, electric roller shutters, aluminum front door, parquet or high-quality laminate, ceiling spots and converted attic. We still have time, the plots are being developed at least until mid-2025.

Plot costs:
Purchase price for 330m² = approx. €153,450
Property transfer tax = €9,974.25 (6.5% of the plot)
Notary/land register = €2,301.75 (1.5% of the plot)
no realtor
Development = €15,000 (flat rate house connections etc.)
no preparation
Sum: €180,726

Building costs:
Shell construction: €240,000 (walls, roof, insulation, brick cladding, windows)
Base plate: €23,000 (incl. structural analysis, insulation)
Interior finishing: €100,000 (heat pump, central ventilation, electrical, underfloor heating, doors, photovoltaic system, electric roller shutters, sanitary fixtures, painting, floor coverings)
Outdoor facilities: €23,520 (prefab garage ideally connected to the house by door, paths, terrace, lawn, hedges, fences)
Architect: €29,000 (all performance phases, can be done by an acquaintance of ours, cost fixed, no billing according to HOAI)
Building permits: €3,528 (flat rate, site setup, incl. building application)
Surveying: €3,500 (flat rate)
Soil report: €1,500 (flat rate)
Building inspection: €2,500 (flat rate)
Earthworks: €12,500 (flat rate)
Insurances: €1,000 (flat rate)
Additional interior equipment: €40,000 (kitchen, new furniture)
Sum: €480,048

Total costs: €660,774
+ Buffer: €57,605 (12% of building costs)
Total sum: €718,379

First, independent of financing, subsidy jungle, and equity. Is this realistic?

I am grateful for any experience.

Best regards Christian

Total: €480,048

Let's take out the interior fittings, because they have exactly nothing to do with the house construction. The new jacket also has nothing to do with the car purchase.

Then there remain €440,000 for 140 sqm house/terrace/garage/ancillary building costs. That is just €3,140 per sqm/living area.
Normally today you calculate around +/- €3,000 per sqm pure construction costs. Without terrace. Without ancillary building costs. Without garage.

For your interior finishing with €100,000 I would put a big question mark
- €40,000 for heating with underfloor heating
- €25,000 electrical
- €10,000 ventilation
- €10-15,000 floor coverings
- €15,000 painter
etc.

Let's exclude the interior fittings, because they have exactly 0 to do with house construction. The new jacket also has nothing to do with buying a car.

Then there remain €440k for a 140sqm house/terrace/garage/incidental construction costs. That’s just €3,140 per sqm/living area.
Normally nowadays you calculate +/- €3,000 per sqm pure construction costs. Without terrace. Without incidental construction costs. Without garage.

For your interior fittings with €100k I would put a big question mark
- €40k for heating with underfloor heating
- €25k electricity
- €10k ventilation
- €10-15k floor coverings
- €15k painter
etc.

Hello Nordanney,
thanks first of all for your reply. Which costs are realistic according to my breakdown above?
€3,000 pure construction costs suggest €420,000 instead of the €363,000 for shell construction, interior fittings and foundation slab. Is that where the delta lies?

3,000€ pure construction costs suggest 420,000€ instead of 363,000 for shell construction, interior finishing, and base slab. Is that where the difference lies?

Yep. That’s the house, after all. Although it could also be 2,950€ or 3,450€, depending on the building location, ground issues, your wishes. It gets really interesting if your semi-detached house partner, for example, wants to build with a basement.

Apart from that, it is currently not foreseeable how prices will be in 2025. For example, the collective bargaining round for the main construction industry is currently underway – so expect at least a 10% increase in labor costs. On the other hand, the demand for craftsmen is continuously declining – craftsmen are looking for work.

I WOULD calculate with at least 3,200€/sqm and be happy if there is money left later or if I don’t have to fully use the loan / equity (consider it a buffer you should have anyway).

Understand your argument. I had already included a buffer anyway. The times are quite uncertain at the moment for a stable calculation, hence my potential for follow-up questions. At €3,200/m², I end up with about €600,000 for the total building costs. Overall, the sum would increase to about €840,000. That already makes me a bit dizzy. Of course, you could also build smaller.

How much personal contribution can be expected from a builder? We are not exceptionally skilled in handiwork. I would trust us to paint and lay floors. We would have support on the side from some acquaintances (electrician, my brother-in-law is a site manager and could negotiate individual trades). We will have about €82,000 in equity by 2025, and about €100,000 in equity by 2026. Not much, given the high construction sum. KFW40 funding for families could possibly be added, but even the €170,000 is by no means enough. A total net income of €4,900 per month also does not allow for a huge loan installment.

Are the €3,200 based on a turnkey construction? We could also represent individual trades through my brother-in-law. We have some contacts there. Would that help?

You save 15k per year but want to spend 40k on kitchen and furniture? That will be a tight squeeze even without such spending behavior.