Underground house: building permit in Slovenia 2026

The short answer

Slovenian law has no separate category for an "underground house". A house partly or fully set into the ground and covered with earth is a single-family dwelling. The same acts, spatial plans and technical regulations apply to it as to any other house. You need no special permit, but you do need a design that meets these requirements.

Under the Decree on the classification of structures, a building becomes a demanding structure only with three or more underground storeys or with underground parts deeper than 15 m. A single-storey earth-sheltered house is therefore a less demanding structure, just like a conventional house.

Which regulations apply and who decides

Acts, spatial plans and the competent authority

Building Act (GZ-1), Official Gazette of the Republic of Slovenia no. 199/21, last amended by GZ-1B (75/25): building permit, notification of the start of construction, occupancy permit.
Spatial Management Act (ZUreP-3): municipal spatial plan (OPN), municipal detailed spatial plan (OPPN), location information and location verification.
Your municipality's OPN and OPPN: what you may build, how high, with what roof and how far from the boundary.
The competent authority is the administrative unit for the area where the house will stand. You file the application electronically via eUprava (the eGraditev system), by post or in person.

Deadlines and fees

Opinion-givers (the municipality on compliance with the OPN, utility network operators and, where needed, the Slovenian Water Agency) must issue their opinion within 30 days.
The administrative unit decides within two months of a complete application, or three months if it has to reconcile opinions. If you enclose positive opinions and written consents from all parties to the procedure (normally the neighbours), it may issue the permit in a shortened procedure within 30 days (Article 62 of GZ-1). The appeal period is 8 days.
The administrative fee for a building permit depends on the value of the structure (tariff no. 40 of the Administrative Fees Act) and comes to a few hundred euros for a family house; the occupancy permit costs EUR 9.10. Young families are exempt from these fees.
The largest cost of the procedure is usually the utility contribution, assessed by the municipality and payable before the building permit is issued.
A building permit lapses if you do not start construction within five years of it becoming final.

The plot first: what the OPN must allow

The most important step comes before you buy the land. You may only build on building land whose designated use allows residential buildings. As a rule, agricultural and forest land does not.

How to check a plot

In the Spatial Information System check the designated use, the spatial planning unit (EUP) and the spatial plan in force.
Order location information from the municipality (Article 279 of ZUreP-3). It covers the designated use, the spatial plans, including those in preparation, and the legal regimes (flood or landslide areas, cultural heritage, Natura 2000). The fee is EUR 35.00.
Ask for a consultation at the municipality and the administrative unit. Under Article 45 of GZ-1 they must give you basic information on the procedure and the spatial plan.

The OPN provisions that most often decide the matter for an earth-sheltered house

Roof shape: in many rural areas the OPN prescribes a pitched roof at a set angle. A flat green roof is possible only if the OPN allows it for your EUP.
Number of storeys and height (for example basement, ground floor and attic) and the definition of a basement: municipalities define this differently. Koper, for instance, counts a basement as partly set into the ground if it is dug in on at least three sides.
Site coverage ratio, floor area ratio and the share of green space: ask whether the municipality counts a green roof as green space.
Setbacks from the plot boundary and the building line.
Rules for excavations, embankments and retaining walls.

What if the OPN does not suit

ZUreP-3 provides for location verification (Articles 134 to 140). At the client's initiative, and on the basis of a study, the municipality may permit an individual departure from the spatial implementation conditions. Among the objective circumstances the act expressly lists the physical characteristics of the land, such as a steep slope, and technical solutions that are better than those prescribed in terms of efficient energy use. The departure must not worsen living conditions or reduce the development potential of neighbouring land. The decision is valid for five years. The longer route is to amend the OPN.

What is specific to an underground house and how it is resolved

Natural light and a view out

The Rules on minimum technical requirements for the construction of residential buildings and dwellings (Article 14) require rooms used for living, sleeping and preparing and eating food to be naturally lit:

the area of the window openings must be at least 20% of the net floor area of these rooms, counting only the part of the opening more than 0.50 m above floor level;
a room lit from one side only may be at most three times the clear height deep (so 7.50 m at a height of 2.50 m);
at least one opening in the living room must have a sill no higher than 0.90 m and give a view of the outside;
a dwelling with more than three bed spaces must not be lit solely by windows facing between north-east and north-west;
with light wells, the sun must reach part of the floor of the well at least once a year, and rooms beside the well must not light other rooms indirectly.

The clear height of living rooms must be at least 2.50 m (Article 12). An earth-sheltered house meets these requirements with a glazed open facade facing south, east or west, together with rooflights. In Talpa House houses, rooms from 6 to 8 m deep are well lit in this way too.

Basement or living space

The regulations do not prohibit habitable rooms below ground level. Whether a room counts as habitable is determined by light, height and ventilation, not by how much earth sits above it. Do check, however, how your municipal spatial plan (OPN) counts storeys: if the buried part is treated as a basement, this affects the permitted number of storeys, the plot ratio and the setbacks.

Fire safety and exits

The designer demonstrates fire safety with a fire safety statement under technical guideline TSG-1-001. For a single-storey detached house, the guideline sets no fire resistance requirements for the load-bearing structure. In an underground house the key point is that habitable rooms have direct access to the outside through the open facade. Rooms without a facade, or long internal escape routes, are resolved by the designer with an additional exit, for example through a courtyard.

Setbacks, height and earth on the roof

Setbacks are set by the municipal spatial plan, not by national regulation. They are often 4 m from the plot boundary, and may be smaller with the neighbour's written consent. Some spatial plans also measure setbacks for the underground parts of a building, so check this. For height, establish the level from which the plan measures it (existing or finished ground level) and whether the earth placed on the roof counts towards the building height.

Structure, waterproofing and radon

The load-bearing structure is sized for the load of the soil and the green roof by a chartered civil engineer in accordance with the Eurocodes, and a geological and geotechnical report is required for the excavation and foundations. In Slovenia the watertightness of concrete is normally specified by a water penetration resistance class (PV) under standard SIST 1026. Talpa House builds in watertight monolithic concrete on the white tank principle.

For new buildings with habitable rooms the radon reference level is 300 Bq/m³. Technical guideline TSG-1-007:2023 requires a permeable layer at least 10 cm thick beneath the floor slab, with radon pipework. In radon-prone areas (including Postojna, Idrija, Kočevje, Logatec and Sežana), passive or active soil depressurisation or full sealing is added.

Energy efficiency

A new building must be nearly zero-energy under the Rules on the efficient use of energy in buildings (PURES, Official Gazette of the Republic of Slovenia, no. 70/22 as amended), which the designer demonstrates with a building physics report. For a new house that you neither sell nor let, the obligation to provide an energy performance certificate under the ZURE act is met by the building energy performance statement. You need an energy performance certificate when selling or letting for more than one year.

Who signs the design and which documents are needed

The design documentation is signed by the designer and the lead designer, a chartered architect or engineer. For a house this is usually an architect on the register of the Chamber of Architecture and Spatial Planning of Slovenia (ZAPS). The structural, services and building physics designs are signed by chartered engineers registered with the Slovenian Chamber of Engineers (IZS). An architect from another EU country may work in Slovenia on the basis of a notification to ZAPS for the temporary or occasional provision of services.

DGD, the documentation for obtaining opinions and the building permit, with a statement from the designer and the lead designer that it complies with the regulations and with the spatial plan;
opinions from the competent authorities;
proof of the right to build (entry in the land register or, for example, a certified contract);
proof of minimum utility provision;
after the permit is issued, the PZI, the design documentation for construction, and the appointment of a supervisor;
at the end, the as-built design (PID) and the supervisor's statement.

The procedure step by step

Before buying land, check the plot in the PIS spatial information system and order a location information report.
Go through the municipal spatial plan with your architect (roof, number of storeys, setbacks). If needed, apply for a location review.
Order a land survey plan and a geological and geotechnical report.
The architect prepares the DGD, if you wish on the basis of design conditions (15 day deadline).
Obtain the opinions of the competent authorities (30 day deadline).
File the building permit application with the administrative unit and pay the utility contribution. The decision follows within two to three months, or within 30 days under the shortened procedure.
Once the permit is final, have the PZI prepared, appoint a supervisor, order the setting out and register the start of construction.
Construction follows, and at the end the designer prepares the as-built design (PID).
Within 30 days of completion, apply for the occupancy permit. A less demanding building requires no technical inspection and the administrative unit decides within 15 days. The occupancy permit is a precondition for assigning a house number.

How Talpa House works with you

At Talpa House (Pribila spol. s r.o., Slovakia) we have been designing and building earth-sheltered family houses in watertight monolithic concrete with a green roof since 2010. We have built more than 21 of them in Slovakia, the Czech Republic and Hungary. The turnkey package includes the design and support through the permit procedure. We have not yet built in Slovenia and are looking for local partners. The building permit documentation will therefore be signed by a chartered architect registered with ZAPS, with whom we will work, while we contribute the concept, the details and our experience with earth-sheltered houses.

You can work out an indicative price in the calculator, and find a breakdown of costs in the guide to underground house prices. You are welcome to see a house in person, and for questions about your plot simply write to us.

Frequently asked questions

I read on a forum that this is "almost mission impossible". Is that true?

That assessment comes from a 2012 discussion on the podsvojostreho.net forum. The obstacle was not building legislation but the provisions of spatial plans on roofs and storeys, which you still need to check for every plot. Since then the new Building Act and ZUreP-3 have come into force, and the location review procedure expressly allows a departure from the plan for more energy-efficient technical solutions. Where the spatial plan permits a green flat roof, or the municipality approves a departure, the procedure is the same as for a conventional house.

Do I need a sloping plot?

The law does not require one. On a slope, a house dug into the hillside is the easiest to build: the facade faces the valley and the excavation is smaller. On a flat plot you build up earth around the house, in which case check the spatial plan rules on earth banks.

Do I need the neighbours' consent?

Only if the house does not meet the setback that the municipal spatial plan allows solely with the neighbour's consent, or if you want the shortened procedure. Otherwise, neighbours may be parties to the proceedings and submit comments.

How long does the procedure take?

The statutory deadlines are 30 days for opinions and two to three months for the decision. With the plot check and the design, allow six months to a year, and longer if a location review is required.

Are damp and radon a problem in an underground house?

Not if they are dealt with in the design: watertight concrete, drainage, radon protection to TSG-1-007 and well-considered ventilation. Ventilation in Talpa House homes is passive.

Please note

This is general information, not legal advice. Rules differ from one municipality to another, so always check the municipal spatial plan in force for your plot and consult the municipality or the administrative unit. Legislation as at October 2026.

Underground family house: building permit for an earth-sheltered house in Slovenia