Hyppää sisältöön

Change of use

A change to the registered official use of a building always requires a permit procedure. For example, changing a holiday home into a permanent residence constitutes a change of use.

A change of use for a building, such as converting a recreational dwelling into a permanent residence, always requires a permit procedure. As a general rule, a change of use necessitates applying for both a deviation permit (an administrative permit procedure that enables the application for a building permit) and a building permit (which implements the change). In colloquial speech, recreational dwellings are often referred to as ‘mökki’ (cottage), ‘loma-asunto’ (holiday home), or ‘vapaa-ajan asunto’ (recreational dwelling).

When planning to convert your building for permanent residential use, it is first important to ascertain the building’s current registered use.

Order register and map data concerning your building and property (in Finnish)

Once you have confirmed the current use of your building, you can begin preparing the planning for the change of use. During the planning phase, building industry experts (designers) will determine in more detail under what conditions the change is possible and how it meets:

  • land use requirements
  • technical requirements

In some cases, the use recorded in the building register does not correspond to the use specified in the building permit. However, the actual use of the building does not form a basis for changing its registered use. If you suspect a registration error, you can submit a registration correction application via the electronic Lupapiste service or contact the building inspector in your area, who will advise on matters concerning registration error correction.

Mandatory designers you will need during the planning phase:

  • principal designer
  • architectural designer (usually the principal designer also acts in this role)
  • energy performance assessor
  • On a case-by-case basis, you may also often need:
  • HPAC designer
  • structural designer

Where can I get initial information?
It is the responsibility of the project initiator to acquire accurate information, which can be sought from the following sources, for example:

  • You can order building permit documents archived by the authorities from the building control archive / city archives
  • From the property owner’s own documents and archives
  • From principal, architectural, and specialist designers
  • Through an inventory conducted at the building site: for example, measurements of the building’s extent, property surface levelling, and structural openings

The objective of reviewing land use requirements (zoning situation) is to ascertain whether the current situation of the building site allows for permanent residence on the site.

For shoreline areas, the priority zones defined by the city significantly determine the possibility of a change of use. You can find out more about:
Construction in shoreline areas (zoning)
Priority Zone Map (shoreline areas, in Finnish)

General requirements for a building site for permanent residence:

  • The building site must be of sufficient size and shape, at least 3000 m2 (1000 m2 if the site is outside a shoreline area and connected to the public sewerage network)
  • The building site must have a legal wastewater system if connection to a centralised wastewater network is not possible
  • The building site must have a sufficient supply of good quality domestic water
  • The building site must be located along a good road connection, accessible year-round by rescue and maintenance vehicles
  • Placement of the building on the plot (e.g., distance to shoreline, neighbour)

Converting a recreational dwelling for permanent use requires meeting the technical requirements set for residential buildings. The necessary modification measures vary by building project. It is the applicant’s responsibility, with the help of the principal designer, to identify the necessary modification measures and present them in the documents attached to the building permit application (main drawings and reports). Often, these measures relate to energy efficiency.

If all requirements cannot be met, the principal designer must propose minor deviations from the technical requirements, with justifications, in connection with the building permit application.

Key technical requirements:

  • Requirements related to dwelling design
    • room size and height
    • window/light opening requirements
    • dwelling area requirements
    • general space requirements for dwellings
  • Energy efficiency. Compliance with requirements can be assessed using three different methods:
    • compliance with component-specific requirements
    • compliance with the calculated energy consumption of the building
    • compliance with the building’s total energy consumption, i.e., the E-value
  • Operational safety and accessibility
  • Indoor climate and ventilation
  • Wastewater system (following the Ministry of the Environment’s wastewater guide for sparsely populated areas, HML environmental protection regulations, and building regulations)

The following documents must always be attached to a change of use permit application:

  • Report on the control of the building site
  • Site plan
  • Floor plans
  • Section drawings
  • Elevation drawings
  • Energy performance report
  • Ventilation plans or report on ventilation
  • Report or plan on meeting wastewater system requirements
  • Neighbour consultation
  • Adjoining property owners
  • Water area holders (e.g., water cooperative)
  • Holder of the connecting road
Last updated 19.10.2026