What are the costs of an addition to a house in South Holland? Here is a detailed overview of prices in 2025

Homes turn out to be small. That strange feeling when you enter your home and notice that there is not enough space for you. Maybe you want more living space to have a nice coffee, or a workspace for better performance. Recognizable? More and more people in South Holland are opting for an extension to make their home more comfortable while increasing its value. But what will such an extension actually cost in 2025? In this post, we give you a clear overview of the average cost of an extension and discuss various factors that affect it.

1. What do you pay on average for an extension in South Holland?

An extension is a big investment. The average cost is between €15,000 and €25,000, including VAT, materials and installation. The final price depends on your needs, preferences and budget. Physical and environmental factors, such as the location of the house or the state of the foundation, can also affect the cost.

The table below provides an overview of the cost of an addition:

Type of extension	Average size	Cost per m²	Cost total
Prefab standard design	12,5 m²	€1.440	€18.000
Prefab luxury version	12,5 m²	€2.010	€25.125
Custom wood frame construction	12,5 m²	€1.710	€21.375
Custom traditional masonry	12,5 m²	€1.980	€24.750
Custom concrete construction	12,5 m²	€2.380	€29.750

2. What are the main factors that determine price?

The size of the addition.

You may be thinking: bigger is always more expensive. That's true, because you are obviously paying for the extra square footage. But if you look at the price per square foot, the larger the extension, the cheaper it often becomes. This is because many costs, such as the permit and foundation, are fixed amounts and are therefore better distributed over a larger area. As a result, you will pay relatively more per sq. ft. for a small addition than for a larger one.

Construction method: prefabricated or custom. Prefabricated additions are largely made in the factory and installed on site. This saves time and labor costs. As a result, prefab is usually less expensive than traditional custom construction, although it offers less design freedom. Custom is built on site and offers maximum flexibility in shape, materials and finishes. The downside is higher costs and longer construction time.

Choice of materials and finishes. Will you choose standard plastic window frames or hardwood with luxury stained glass windows? Will you go for a flat cement floor or a tiled floor with underfloor heating? Every choice counts. In particular, roof finish, insulation, wall coverings, stucco and installations can significantly affect the final price.

Foundation and soil conditions. South Holland is known for its swampy soil and water levels are often high. This makes a solid foundation essential and sometimes expensive. You may have to deal with piles or special foundation techniques. The costs for these range from several hundred to thousands of extra euros.

Permits and architectural drawings. An extension more than 4 meters deep or if you change the structure of the house requires an environmental permit. The cost of this varies by municipality, but keep in mind a few hundred euros. Some projects also require a structural engineer or architect.

Labor costs and location. Do you live in a downtown area with limited truck access? Or in a neighborhood where work can only be done by hand? Then labor costs can add up. This is especially relevant in old city areas of Delft, Leiden or Dordrecht, for example.

The time to involve Global Bouw

Are you planning an extension to your house to make it even cozier? But are you confused by the many small nuances in costs and do not know what fits best within your budget? Then Global Bouw is happy to come to your rescue.

We have been in the construction business for years and are happy to help you. With our commitment, we make sure that your dream of an addition becomes a reality. Our specialists carefully review your needs, preferences and budget to determine the price and recommend the most suitable type of addition for you. Contact us today and forget your worries about the cost of your addition.