Sokkelleilighet
A sokkelleilighet (basement apartment) is a separate dwelling unit on the lower ground floor or in the basement of a detached house, with its own entrance and normally its own kitchen and bathroom. To be lawful as an independent dwelling, it must be approved as a bruksenhet (use unit) by the municipality and meet the requirements in byggteknisk forskrift TEK17 (the building technical regulations).
Sokkelleilighet is not a formal legal category, but a common term for what the matrikkelen records as a separate dwelling unit in a building classified as enebolig med hybel/sokkelleilighet (building type 112) or tomannsbolig (two-dwelling house). The difference between a rented room with no separate status and an approved sokkelleilighet matters in practice: only approved dwelling units have their own bruksenhetsnummer (dwelling number), can be registered with their own postal address, and can be let as an independent dwelling under husleieloven (the Tenancy Act). A basement flat that is not approved but is let as a dwelling is an unlawful measure under plan- og bygningsloven (the Planning and Building Act), and the municipality can require reinstatement or an application for change of use.
The requirements for rooms and living space in TEK17 § 12-7 apply regardless of which floor the dwelling unit is on. The most important ones are clear internal ceiling height, light and escape conditions, and fire safety. For habitable rooms, the general rule is a ceiling height of at least 2.4 m, but basement dwellings are often accepted down to 2.2 m in older buildings during a bruksendring (change of use) if the overall solution is sound. Every habitable room and bedroom must have an escape window with a clear opening at least 0.5 m wide and 0.6 m high, where the sum of the width and the height is at least 1.5 m, under TEK17 § 11-13. In addition, TEK17 § 13-5 on radon applies: basement dwellings must have a radon barrier in the ground and provision for measures if the action level of 100 Bq/m³ is exceeded.
If an existing basement is to be converted into a sokkelleilighet, this is normally a bruksendring that requires an application under plan- og bygningsloven § 20-1, first paragraph, letter d. It requires a byggesøknad (building application), an ansvarlig søker (responsible applicant) and a ferdigattest (completion certificate) or midlertidig brukstillatelse (temporary permission to occupy) before anyone moves in. Many municipalities have their own guides for basement dwellings, covering requirements for window areas, ceiling height, ventilation and parking. After completion, the dwelling unit is assigned a bruksenhetsnummer and is registered in the matrikkelen and the National Population Register.
For tax purposes, a distinction is made between letting part of your own primærbolig (primary dwelling), which is tax free for up to 50% of the rental value, and letting a sokkelleilighet that is an independent dwelling unit (the same rule applies as long as the owner lives in the rest of the house). If the owner of the detached house later sells it, an approved sokkelleilighet will typically increase the market value by the capitalised rental income plus a quality premium for flexibility.
In Placepoint you can see the registered bruksenheter for each building in the Building panel, including which category they are registered as and which dwelling number they have. That makes it easy to check whether an advertised sokkelleilighet is actually approved as a separate dwelling unit before you go ahead with a transaction or a valuation.
How it looks in Placepoint
In Placepoint you find this in the Building panel:
From Placepoint's dictionary: Sokkelleilighet
More information: DiBK: TEK17 § 12-7 on the design of a dwelling unit, DiBK: TEK17 § 13-5 on radon, Skatteetaten: letting a dwelling
English: Basement apartment.
Frequently asked questions
What is a sokkelleilighet?
A separate dwelling unit in the basement or on the lower ground floor of a detached house, with its own entrance, kitchen and bathroom. To be lawful for letting, it must be approved as a bruksenhet by the municipality.
What is the difference between a hybel and a sokkelleilighet?
A hybel (bedsit) is typically a single room with limited independence, often sharing a kitchen or bathroom with the main dwelling. A sokkelleilighet is an independent dwelling unit with its own bruksenhetsnummer and its own postal address.
What are the requirements for ceiling height?
TEK17 requires, as a general rule, 2.4 m clear internal height in habitable rooms. During a bruksendring of older buildings, heights down to 2.2 m are often accepted, following a case-by-case assessment by the municipality.
Does a sokkelleilighet need an escape window?
Yes. Every habitable room and bedroom must have an escape window with a clear opening at least 0.5 m wide and 0.6 m high, where the sum of the width and the height is at least 1.5 m, see TEK17 § 11-13.
Does converting a basement into a sokkelleilighet require an application?
Yes. A bruksendring from basement or storage room to a dwelling unit requires an application under plan- og bygningsloven § 20-1 and requires an ansvarlig søker, a ferdigattest and registration in the matrikkelen.