Gain more living space with a house extension: a cost overview


If the plot is big enough and an official building permit is available, nothing stands in the way of house cultivation. We will inform you about the costs incurred so that you can keep track of everything right from the start.

You have to take these costs into account when you grow the house

The following list serves as a rough overview of the various cost factors in house cultivation. So you have the possibilities to calculate each item individually.

  • The first costs on your total bill concern the earthworks on your property.
  • Would you like a cellar - or a base plate? The square footage of the cultivation is also included in the price.
  • Immediately thereafter, the costs for the masonry work come to you. Or, if a prefabricated house cultivation is to arise, the price for material and assembly.
  • Include a good thermal insulation in your bill.
  • You may need to extend your central heating to effectively heat the new living space. Ask your sanitary specialist if the heating capacity is sufficient!
  • Also think of pipes and electrical equipment for your house cultivation.
  • Windows and doors account for a surprisingly high proportion of the total bill.
  • Pent roof, pitched roof, hipped roof, flat roof: You have the choice of roof construction - and thus very different costs.
  • The type of covering your cultivation is crucial for the total price.
  • Does your extension need its own staircase? This also provides extra costs.
  • Painting on the façade is unavoidable in most cases. Maybe you can do some things yourself here?
  • Now the interior is missing: Also here you expect relatively high bills, if you have everything done by a specialist.

Percentage cost key

For a simple, two-storey extension without special extras you should expect a price of at least 500 EUR per square meter. However, the project often costs 1000 EUR per square meter and more, especially if there is little personal contribution.

Gain more living space with a house extension: a cost overview: house

The shell costs you about half of the total price. After all, with 50% of your budget you will reach the topping-out ceremony.

Plaster, insulation and paint again demand about 10% of your construction costs. Added to this is about 20% for the plumbing and heating.

A construction project as a cost example

A family plans to expand the house on its own property, 80 square meters of living space are added to the old building. The cost estimate in this case looks like this:

Cost overviewprice
1st shell including bottom plate40,000 EUR
2. Covering5,000 EUR
2. Sanitary and electrical15,000 euros
3. Thermal insulation6,000 EUR
4. Painting inside and outside12,000 EUR
total78,000 euros

Extras increase the costs!

Special extras such as a dormer window, a balcony, a porch or a new entrance portal are optional added to the price. These details are often very important in terms of price.

Tips & Tricks

Calculate from the outset the construction costs, such as the regulatory approvals, surveying and fire safety.


Video Board: How to plan and cost a single-storey extension