Local detailed plan – what is it and why does it matter for building?

The local detailed plan (asemakaava) lays down with binding force for what purpose, where and how much you may build on a plot. The municipality draws up and approves these plans, and every building permit is granted on the plan's terms. Before buying a plot, the plan extract and plan regulations are therefore the most important documents to read.

The legislation changed at the start of 2025: construction provisions moved into the new Building Act (rakentamislaki), and the remaining planning part of the old Land Use and Building Act became the Land Use Act (alueidenkäyttölaki). The planning system itself is unchanged: the regional plan steers the local master plan, which steers the detailed plan – the most precise level.

What does the local detailed plan tell you?

• Permitted use: the plan notation states what may be built – for example, AO denotes an area for detached houses and RA an area for holiday homes.
• Building right: given either directly in square metres of gross floor area or as a plot ratio e – for example, e=0.25 gives a 1,000 m² plot 250 m² of gross floor area.
• Building area: the part of the plot where a building may be placed.
• Number of storeys, and often roof shape, facade materials and colouring.
• Other regulations: parking spaces, areas to be planted, noise abatement.

A plan is read in two parts: the plan map and its regulations. The municipal building control office and map services help with interpretation.

Does the plan also bind permit-exempt building?

Yes. Under the Building Act, an outbuilding under 30 m² or a shelter under 50 m² may be built without a building permit (rakentamislupa), but the exemption does not override the plan. Even a permit-exempt garden sauna or store consumes the plot's building right and must comply with the plan's building area and regulations. If the building right is used up, or the building departs from the plan, the exemption does not apply, and the municipality can intervene afterwards. Responsibility for compliance then rests entirely with the builder.

What if the project departs from the plan?

A minor deviation from the plan can now be approved directly in the building permit, without a separate process. A more substantial conflict still requires a separate deviation permit, decided by the municipality. Outside detailed-plan areas, in planning-need areas, the preconditions for building are assessed in the building permit or a separate siting permit – the old stand-alone planning-need decision no longer exists.

Special features of shore areas

On shore areas, building is steered by the shore master plan and the shore detailed plan. The latter has a peculiarity: the landowner may draw one up for their own shoreline, and the municipality approves it. If the shore has no plan designating a building site, construction requires a deviation permit. A waterfront buyer should therefore check the planning situation especially carefully – an unplanned shore can mean months of proceedings with no certainty of outcome.

The planning levels in brief: from regional plan to detailed plan

Regional plans are drawn up by the regional councils and steer land use broadly. The local master plan is the municipality's general plan, designating areas for housing, services and recreation. The detailed plan refines it down to plot and block level. For a builder this is practical: in a detailed-plan area the permit conditions are read straight from the plan, while in an unplanned area the municipality weighs the siting conditions case by case. A master plan can also steer permits directly, like a shore master plan.

Why read the plan before buying a plot?

The plan directly affects the plot's value and the kind of house that can be built. The same plot can suit one house type and be impossible for another: it may require two storeys, dictate the ridge direction, or prohibit a facade material. Anyone building a log house should check whether the facade regulations allow a log surface – most detached-house areas do, dense urban areas can be strict.

Amending a plan is the municipality's decision and includes consulting the parties concerned. It is a slow road – better to choose a plot whose plan already suits your intentions, or to fit the house to the plan's terms at the drawing board with your principal designer. A new Land Use Act in preparation would streamline planning but is not yet in force. It proposes joint processing of master and detailed plans and a landowner's right to initiate a plan – worth watching, but for now decisions follow the current law.

Three checks before the purchase: the plot's permitted-use notation, how much building right remains, and whether the intended house fits within the plan's building area. With those in order, the permit stage rarely founders on the plan.

• The local detailed plan lays down, with binding force, the permitted use, building right, building area and number of storeys.
• Since 1 January 2025 planning has been governed by the Land Use Act – the former Land Use and Building Act under a new name.
• A plot ratio of e=0.25 means 250 m² of gross floor area on a 1,000 m² plot.
• The plan also binds permit-exempt buildings under 30 m² – they too consume building right.
• A minor deviation from the plan can be approved directly as part of the building permit.
• Read the plan map and regulations before buying a plot – the municipal building control office will help with interpretation.