ᐅ Cost Estimation for a Semi-Detached House – Experiences

Dear Homebuilding Forum,

I have read several threads and researched a lot online. However, the estimates for the construction costs of a semi-detached house vary widely. Therefore, I have created a detailed calculation and would like to know whether it can be considered realistic.

Basics: Family with one child, building a semi-detached house on a slab foundation, approximately 140m² (1505 sq ft), KfW40 energy standard without QNG, architectural planning, brick façade, pitched roof, expanded terrace, large garage for one car plus 1–2 bicycles and storage, heat pump or district heating, photovoltaic system, possibly required central ventilation, electric roller shutters, aluminum entrance door, parquet or high-quality laminate flooring, ceiling spots, and finished attic. We still have time, as the plots will not be developed until at least mid-2025.

Plot costs:
Purchase price for 330m² (3550 sq ft) = approx. €153,450
Land transfer tax = €9,974.25 (6.5% of the plot)
Notary/land registry = €2,301.75 (1.5% of the plot)
No real estate agent
Development costs = €15,000 (flat rate for house connections, etc.)
No site preparation
Total: €180,726

Building costs:
Shell construction: €240,000 (walls, roof, insulation, brickwork, windows)
Slab foundation: €23,000 (including structural engineering, insulation)
Interior finishing: €100,000 (heat pump, central ventilation, electrical installation, underfloor heating, doors, photovoltaic system, electric roller shutters, sanitary fixtures, painting, floor coverings)
Outdoor facilities: €23,520 (prefabricated garage ideally connected to the house by a door, paths, terrace, lawn, hedges, fences)
Architect: €29,000 (all service phases, can be done by an acquaintance, fixed cost, no billing according to HOAI)
Building permits: €3,528 (flat rate, site setup, including building application)
Surveying: €3,500 (flat rate)
Soil report: €1,500 (flat rate)
Building inspection report: €2,500 (flat rate)
Earthworks: €12,500 (flat rate)
Insurance: €1,000 (flat rate)
Additional interior fittings: €40,000 (kitchen, new furniture)
Total: €480,048

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

This is regardless of financing, subsidy complexity, or own equity for now. Is this realistic?

I appreciate any experience you can share.

Best regards,
Christian

Chris512 schrieb:

Total: €480,048

Let’s exclude the interior fittings, since they have nothing to do with the actual house construction. Just like a new jacket has nothing to do with buying a car.

That leaves €440,000 for a 140 m² (1,507 sq ft) house/terrace/garage/additional construction costs. That’s only about €3,140 (USD approximate equivalent) per m² (sq ft) of living space.
Normally, you would calculate around €3,000 (USD approximate equivalent) per m² (sq ft) purely for construction costs nowadays. Without terrace. Without additional construction costs. Without garage.

Regarding your interior finishing with €100,000, I would have serious doubts:
- €40,000 for heating with underfloor heating
- €25,000 for electrical installation
- €10,000 for ventilation
- €10,000–15,000 for flooring
- €15,000 for painting
etc.

nordanney schrieb:

Let's exclude the interior finishing since it has absolutely nothing to do with the house construction itself. A new jacket also has nothing to do with buying a car.

That leaves €440,000 for a 140 sqm (1507 sq ft) house/terrace/garage/incidental building costs. That amounts to just €3,140 per sqm (291 sq ft) of living space. Normally, you would calculate around €3,000 per sqm (291 sq ft) for pure construction costs nowadays. Without terrace. Without incidental building costs. Without garage.

For your interior finishing budget of €100,000, I would have a big question mark:
- €40,000 for heating with underfloor heating
- €25,000 for electrical work
- €10,000 for ventilation
- €10,000–15,000 for flooring
- €15,000 for painting
etc.

Hello Nordanney,
thanks first for your reply. Which costs do you consider realistic based on my breakdown above?
Pure construction costs of €3,000 per sqm (291 sq ft) would imply €420,000 instead of the €363,000 for the shell construction, interior finishing, and foundation slab. Is this where the difference lies?

Chris512 schrieb:

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

Yep. That’s basically the house itself. Although it could also be 2,950€ or 3,450€ depending on the building location, soil conditions, and your preferences. It gets really interesting if your semi-detached partner wants to build, for example, with a basement.

Aside from that, it’s currently unpredictable how prices will develop in 2025. For example, the collective wage bargaining round for the main construction industry is coming up now—so expect at least a 10% increase in labor costs. On the other hand, the demand for craftsmen is steadily decreasing—craftsmen are looking for work.

I would calculate with at least 3,200€/m² (300 sq ft) and be happy if later you have money left over or don’t have to fully use your loan or equity (consider it as a buffer that you should have anyway).

I understand your reasoning. I had already included a buffer for that reason. Times are quite uncertain right now for a reliable cost estimate, which is why I have so many questions. At €3,200/m² (approximately $3,400/ft²), I end up with about €600,000 (about $660,000) for the total building costs.
Overall, the total amount would increase to about €840,000 (about $920,000). That is already a bit overwhelming. Of course, you could also build smaller.

How much own work can be expected from a homeowner? We are not particularly skilled with tools. I think we could manage painting and laying floors. We would have some help from acquaintances on the side (an electrician, my brother-in-law is a construction manager and could coordinate individual trades).
By 2025, we expect to have about €82,000 (about $90,000) in equity, and about €100,000 (about $110,000) by 2026. Not a lot, considering the high construction costs. There might be KfW 40 funding for families, but even then, €170,000 (about $185,000) won’t come close to covering everything. Our total net income of €4,900 (about $5,400) per month also doesn’t allow for a very high loan repayment rate.

Is the €3,200 (approximately $3,400) figure based on a turnkey build? We could also arrange individual trades through my brother-in-law. We have some contacts for that.
Would that help?

You save 15,000 per year but plan to spend 40,000 on the kitchen and furniture? That will be a tight squeeze even without such spending behavior.