Attefallshus
Attefallshus is the established name for a permit-free komplementbygning (ancillary building) or komplementbostadshus (ancillary dwelling) that Swedish homeowners could put up next to a detached or semi-detached house. It is named after Stefan Attefall, Swedish housing minister 2010-2014. From 1 December 2025, attefallshus no longer exists as a legal term, but the word lives on in everyday speech and as a search term.
The reform was passed by the Riksdag in 2014 and came into force on 2 July the same year, at that time with an area limit of 25 m². From 1 August 2020, the limit was raised to 30 m² after an amendment to what was then chapter 9, section 4 a of the plan- och bygglagen (2010:900). An attefallshus could be built as a komplementbostadshus, that is, an independent dwelling with its own kitchen and bathroom, or as a komplementbygning without any residential use, for example a studio or a garage. The building had to stand next to a one- or two-dwelling house (en- or tvåbostadshus) that already existed on the plot.
The decisive difference from a friggebod was that an attefallshus was never permit-free in the everyday sense of the word. Even though no application for bygglov (building permit) was needed, the work always required an anmälan (notification) to the byggnadsnämnden, and the developer had to hold a startbesked before work could begin, just as for any other notifiable work. A friggebod, by contrast, required neither bygglov nor anmälan. This difference existed because an attefallshus, unlike a friggebod, could contain a permanent dwelling, and the legislator wanted to make sure the byggnadsnämnden had the chance to check technical requirements such as fire safety, load-bearing capacity and accessibility before anyone moved in.
From 1 December 2025, attefallshus, together with friggebod and a number of related terms, has been replaced by two collective categories in a rebuilt chapter 9 of the plan- och bygglagen (Lag 2025:974): komplementbyggnad and komplementbostadshus. The area is now pooled per plot: inside a detaljplan (detailed development plan), up to 30.0 m² per building and 45.0 m² in total; outside a detaljplan, up to 50.0 m² per building and 65.0 m² in total. Perhaps the most important change is that the notification requirement was removed at the same time: a komplementbostadshus no longer requires an anmälan or a startbesked, even when it is used as a permanent dwelling. The developer still has a duty to follow the technical requirements in Boverket's building rules, but the byggnadsnämnden no longer checks in advance that those requirements are met before anyone moves in.
There is no direct Norwegian counterpart to a dwelling-sized building you can put up without a full building application. Under the plan- og bygningsloven (the Planning and Building Act) and byggesaksforskriften (SAK10, the building application regulations), the exemption from the application requirement for a detached building (§ 4-1 letter a, up to 50 m²) is expressly conditional on the building not being used for residential purposes. If you want to build an independent dwelling unit in Norway, whatever its size, you must apply for byggetillatelse (building permission) in the usual way. The Swedish komplementbostadshus, which can now be built with no anmälan at all even when it is a permanent dwelling, therefore has no Norwegian parallel.
From Placepoint's dictionary: Attefallshus
More information: Boverket: Komplementbostadshus, Riksdagen: Större komplementbostadshus (prop. 2019/20:31), plan- och bygglagen chapter 9
English: A permit-free secondary dwelling under the pre-2025 Swedish rules (Swedish-specific historical term, now replaced by "komplementbostadshus").
Frequently asked questions
What is an attefallshus?
Attefallshus was the established name for a permit-free komplementbygning or komplementbostadshus of up to 30 m² that could be built next to a Swedish one- or two-dwelling house. The term disappeared as a legal concept on 1 December 2025.
Did an attefallshus require an application for bygglov?
No, but it always required an anmälan to the byggnadsnämnden and a startbesked before work could begin. So in practice it was never fully permit-free.
How large could an attefallshus be?
From 2014, the limit was 25 m². From 1 August 2020, it was raised to 30 m², and that limit applied right up to the reform on 1 December 2025.
What is the difference between an attefallshus and a friggebod?
An attefallshus could be used as a permanent dwelling and therefore required an anmälan and a startbesked. A friggebod could never be used as a dwelling, but in return it required neither bygglov nor anmälan.
Can I still build an attefallshus today?
The term is gone, but the substance lives on in what is now called a komplementbostadshus, with a more generous area and no notification requirement.
Is there a Norwegian attefallshus?
No. Norwegian law has no scheme that lets you build an independent dwelling without full byggetillatelse, whatever its size.