Swedish 30 sq m guest house: usually no permit 4.5 m from the boundary

If you want to build a 30-square-metre guest house in your garden in Sweden, you usually do not need a building permit ("bygglov"). New rules have applied since 1 December 2025.

The word "attefallshus" is no longer in the law. The small house is now called a secondary dwelling ("komplementbostadshus"). Many projects also no longer need a notification for the building itself. But there are limits, and the distance to your neighbour matters more than before.

The new rules in brief

The Riksdag approved the changes to the Planning and Building Act ("plan- och bygglagen") on 22 October 2025. They have applied since 1 December 2025. The National Board of Housing, Building and Planning ("Boverket") has summarised the main points:

• The "friggebod" and "attefallshus" exemptions are gone. They are replaced by the secondary building ("komplementbyggnad") and the secondary dwelling.
• Many projects that used to need a notification ("anmälan") no longer need one for the building itself.
• Some projects that are otherwise permit-free need a permit if they are closer than 4.5 metres to the plot boundary.

Guest house: the secondary dwelling

A secondary dwelling is a small house to live in, such as a guest house. It may only be built next to a one- or two-family house. You do not need a permit if the house:

• is at most 30 square metres inside a local development plan ("detaljplan"), or 50 outside
• has a roof ridge of at most 4 metres inside a plan area, or 4.5 metres outside
• is smaller than the house it belongs to
• stands on your plot

Each plot has a shared allowance for these buildings. Inside a plan area it is 45 square metres, outside it is 65. If you build a 30-square-metre guest house inside a plan area, you have 15 square metres left, for example for a shed.

The example: 30 square metres inside a plan area

• Place the guest house at least 4.5 metres from the plot boundary. Otherwise you need a permit.
• If you want to build closer, you can avoid a permit if the neighbours concerned agree in writing. A verbal yes is not enough.
• If the house will have water, drains or ventilation, you must notify the municipality about those installations. You may not start until the municipality has given you a start notice ("startbesked").

Extending your house

You can extend your house without a permit by up to 30 square metres in total. The extension may not rise above the roof ridge. This applies to all kinds of buildings, not just houses. Here too, you need a permit if the extension comes closer than 4.5 metres to the boundary, unless your neighbours have agreed in writing.

A larger extension needs a permit.

Deck

Inside a plan area, you need a permit for a deck ("altan") that is:

• higher than 1.8 metres above the ground and within 3.6 metres of the house, or
• higher than 1.2 metres above the ground and further than 3.6 metres from the house.

A lower deck needs no permit. Outside a plan area this rule does not apply.

When you may still need a permit

The municipality can no longer decide on its own, in the local plan, how much needs a permit. Plan rules that reduce the permit requirement and were adopted under the current Planning and Building Act stop applying on 1 December 2027.

But plan rules that extend the permit requirement still apply. That can be the case in a historic area, for example. Building permits and local plans are also covered in our FAQ.

A permit can also be needed for work that is otherwise exempt:

• if the building or area is particularly valuable
• within 30 metres of a railway
• near certain defence installations

What to do

1. Find out whether your plot is inside a local plan area. The municipality can tell you.
2. Ask the municipality whether the plan extends the permit requirement or whether the area counts as particularly valuable.
3. Measure the distance to the plot boundary. Under 4.5 metres you need a permit or your neighbours' written consent.
4. Add up the area of all small detached buildings on the plot so you stay within the allowance.
5. Notify the municipality if you install water, drains or ventilation, and wait for the start notice.

Sources

• New rules for building permits, Boverket (in Swedish)
• List of Planning and Building Act changes in force from 1 December 2025, Boverket (in Swedish)
• Secondary dwellings, Boverket (in Swedish)
• Decks, Boverket (in Swedish)

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