Building and buying

House extension: how to increase your living area

Torben Schröder

Have you just had a baby? Do you need additional office space after starting your own business? Do you want to realize your long-cherished dream of building a conservatory? Or have your requirements simply changed over time, and do you now feel that your house is too small? These are all good reasons for expanding your living area. If your house no longer meets your requirements, why not consider an extension to gain a few square meters? We explain here what is important and what options you have.

A smaller black building is attached to a large white house.
© Getty Images/ James Osmond

In this article

Planning an extension

An extension is, at least in design, almost as extensive as building a new house. You can achieve the desired result with caution, thoroughness and the help of experts. As the client, you should definitely be aware of the following basic points:

  • The extension must have a defined purpose. If you want more space “just for the sake of it”, you may find that you have bitten off more than you can chew.
  • Your plot of land must be big enough. Depending on whether you want to extend your house in length, width or height, there must be enough space available, in compliance with all the regulations. In some circumstances, the work will make your garden smaller.
  • You must have the necessary financing. An extension can be very expensive. Do you have sufficient reserves? Or have you received confirmation of financial support from your bank?
  • All the permits must have been obtained. In Switzerland, a house extension is a structural change that requires a building permit.
  • You must have a professional architect to oversee the extension project. Without the help of qualified professionals, you will fall at the first hurdle when submitting the building application.

Below, we go into more detail about a few important factors in planning an extension.

Obtain a building permit

You might think that a house that had already received an initial building permit once would not need a new building permit. However, this is a fallacy, because the permit issued at the time was only for the house in its previous form. An extension changes the property and requires a new permit.

The project must also comply with the spatial and building planning laws in Switzerland, as well as the building ordinances of the municipality and the canton. You should check with the relevant authorities and contact an architect at an early stage. Not only will they manage and implement your extension project, but they may also submit the building application.

Bird’s-eye view of a house under reconstruction.

A house extension is usually a very complex and lengthy project – you should approach the planning just as conscientiously.

Choose the architect

The architect will be your right hand during the extension project. They will check all the structural conditions, prepare a presentation of the extension according to your wishes, and finally also submit the building application to the authorities. If at all possible, you should get in touch with the same architect who originally built the house. Recommendations from friends and acquaintances are also helpful. If you don’t have any idea of who to contact, check a central database such as the directory of the Swiss Society of Engineers and Architects (SIA).

Apply for funding

A house extension is always a good opportunity to carry out further modernization or renovation work. You could improve the energy efficiency of the house at the same time, for example. This kind of measure is financially subsidized by certain institutions in Switzerland. Here are two tips:

  • If you want to know how energy efficient your house is, you can have it analyzed by means of a cantonal building energy certificate (GEAK). The result falls into various categories ranging from A (high energy efficiency) to G (low energy efficiency). Some cantons require this certificate for a conversion project anyway. In many places, this analysis is funded through subsidies.
  • Another point of contact regarding subsidies for renovation work is Das Gebäudeprogramm (federal and cantonal funding program). This institution, jointly operated by the federal government and the cantons, is committed to reducing energy consumption and CO₂ emissions.

Type of extension

Lengthwise, widthwise or upwards – you basically have three options for adding to your house. The one you choose will depend firstly on the nature of your plot of land, and secondly on the structural condition of the house. When carrying out an extension, walls – both load-bearing and non-load-bearing – are altered. We present the three types of extension in more detail below.

View into a bright, high room with white furnishings and a glass roof.

Depending on the plot of land and the structural properties of the house, you can extend it in length, in width or even in height – as shown here with an interior extension to create a new kitchen.


This type of extension is suitable if your plot of land is rather narrow, but quite long. During the extension work, the front of the house and original architecture will be left as they are. The main advantage is that the load-bearing walls will only have to be modified or moved on one of the four sides of the house – i.e. at the rear. If your house has a basement, it can also be extended.


Widening a house is quite an unusual method. For one thing, most plots of land in residential areas made up of single-family houses don’t allow any addition to the width because the adjacent properties are so close. What’s more, the construction work is very costly, partly because it involves adapting the roof. Furthermore, it should be noted that the complete appearance of the house will change when viewed from the front.

Increase in height

Strictly speaking, this is not an extension, but a buildup. The structural properties of the house pose the greatest challenge. It’s likely that the upper story of the original construction wasn’t designed for adding any extra height. The structural properties of the building must therefore be thoroughly checked. The zoning regulations must also allow for an addition in height. In general, this measure is suitable for houses on narrow plots of land.

Solid or prefabricated construction?

The most common method of increasing the size of a house is by means of a solid construction. The manual work is similar to that required for a new building. A solid construction allows you to implement your own individual ideas when it comes to material and size – do you fancy a log construction or do you want to opt for a more traditional masonry style, for instance? The extension can also have its own roof. In addition to the great advantage of design freedom, stable masonry also offers benefits in terms of soundproofing, fire protection and thermal insulation. However, you will need to plan a lot of time for a solid construction.

Building an extension comprised of room modules is much faster and less expensive. These prefabricated elements can be made of wood or lightweight aluminum panels, for example. They are enclosed in a metal frame and can be erected very quickly by professionals on site. The construction generally only takes a few days. For one thing, there is no need for any extensive earthwork. If necessary, a prefabricated building can be dismantled just as quickly.

One disadvantage of this method is that you have virtually no influence over the design of the construction. The modules have a predefined floor plan, size, material and appearance. Moreover, the thermal and sound insulation is usually not as good as in a solid construction because of the relatively thin walls.

Wooden house extension

Especially here in Switzerland, wood remains a very popular building material. Even if you don’t own a rustic log cabin in the countryside, but live in a solid brick building in the city, a wooden extension remains a possibility. Due to its relatively low weight, wood is very easy to combine with other materials and usually meets the structural requirements for a property without any problems. The building work is quite inexpensive and can be carried out quickly.

A room with wooden walls. Mountain scenery is visible through the large window.

Even if your house is built of masonry stone, the extension may be made of wood.

Lignum – Holzwirtschaft Schweiz presents an unusual example of a wooden extension. A family from Bützberg wanted to enlarge their living area, but a classic extension in length or width was out of the question on the relatively narrow plot of land. The solution: a “rucksack” extension. The architects docked a “floating” wooden cube onto the existing facade, adding 50 square meters to the family’s living area.

Conclusion: don’t move, extend

Are you comfortable in your home, but would you still like to have a larger living area? Then you don’t necessarily have to look for a new place to live. Check whether it might be possible to simply extend your house. To the rear, to the side or upwards, a solid or a prefabricated construction – there are many different options.

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