Topic
Spotting unauthorised building work
The order to tear it down does not land on whoever built it. It lands on whoever owns the building. After a purchase, that is you.
The ten-minute check
Put the approved plan next to what you actually see. A sunroom, a converted attic, a roofed-over terrace, an extra unit in the basement: if it is missing from the plan, the question is not whether it looks nice, it is whether it was ever approved.
What an unpermitted structure risks
The authority can ban its use and order it removed. Whether it can still do that after years have passed depends on the country, and that is the single biggest difference between them.
Where enforcement never times out
The risk then stays attached to the building permanently, no matter how long it has stood or how many owners it has had since.
Where a deadline applies
Once it passes, the authority can no longer step in. Here is the most common misunderstanding: that does not make the structure lawful, only tolerated. To a bank, and to the next buyer, it remains a defect.
Why it touches the mortgage
A bank values what is actually permitted. Floor area that does not legally exist does not count toward the loan. Someone financing what they believe is 120 square metres, when only 90 are approved, gets less credit than they budgeted for.
The legal position in Germany
When you need a building permit
Building law is a matter for the individual states: each of Germany's 16 states has its own building code (Landesbauordnung). New construction, substantial alterations and changes of use generally require a building permit. Certain smaller projects qualify instead for a simplified exemption or notification procedure.
What happens with unpermitted construction
A structure built without the required permit is formally illegal. Where it also could not have been approved on its merits, the building authority can order its removal. Responsibility falls on whoever owns the property at the time, so after a purchase that means the buyer. Comparing the official building file against what is actually built is therefore essential before signing.
Basis: Set out in the building codes of the 16 states (for example section 63 of North Rhine-Westphalia's building code) and the federal Building Code (Baugesetzbuch, BauGB) for municipal land-use planning.. Last checked against the legal text: 2026-08-18.
The legal position in Austria
When you need a building permit
Building law is the responsibility of the Länder (federal provinces). Each of the nine Länder has its own Bauordnung (building code). New buildings, major alterations, and changes of use require a Baubewilligung (building permit). Smaller projects require only a Bauanzeige (building notification). After completion, a Fertigstellungsanzeige (notice of completion) or a Benützungsbewilligung (permit for use) is required, depending on the Land.
What happens with unpermitted construction
A structure built without a Baubewilligung (building permit) or deviating from it, referred to as a konsensloser Bau (non-conforming building), has no Bestandsschutz (protection of existing use). The building authority may issue a Beseitigungsauftrag (order to demolish or remove), enforceable even against a subsequent purchaser. The buyer assumes this risk. Therefore, reconciling the Bauakt (official building file) with the actual condition, the Konsensprüfung (consensus audit), is central.
Basis: § 129 Bauordnung für Wien and the remaining eight Landesbauordnungen; Flächenwidmung (land-use zoning) and Bebauung (development parameters) under the Raumordnungsgesetz of the respective Land.. Last checked against the legal text: 2026-08-19.
The legal position in Switzerland
When you need a building permit
Building law is governed at cantonal and municipal level. Any new construction, conversion, or change of use requires a building permit from the municipality or the canton. Depending on the canton, a Bauabnahme (formal acceptance of the completed building) is carried out after completion.
What happens with unpermitted construction
Structures built without a building permit are unlawful. The authority may require restoration of the lawful condition, meaning removal of the structure, in some cases even years later. The obligation falls on the owner, and therefore on the acquirer after purchase.
Basis: Cantonal building laws and municipal Baureglemente (building regulations). At federal level, the Raumplanungsgesetz (Gesetz RPG, SR 700) applies.. Last checked against the legal text: 2026-08-19.
The legal position in 30 further countries
This theme also has a legal basis on record for these countries, each with its statute and verification date. Expand your country.
Belgium
When you need a building permit
Building law is regional. In Flanders the Omgevingsvergunning is required, in Wallonia and Brussels the Permis d'urbanisme, each from the municipality. Flanders has restricted the permit requirement to an exhaustive list with effect from 1 March 2026.
What happens with unpermitted construction
A building without a permit or deviating from it (bouwovertreding, infraction urbanistique, building and planning offence) may be criminally prosecuted; the authority may demand restoration measures, up to demolition or disgorgement of the unlawful pecuniary advantage. Regularisation is possible, but not guaranteed.
Basis: Regulated at regional level: the Vlaamse Codex Ruimtelijke Ordening (Flanders), the Code du développement territorial (Wallonia) and the CoBAT (Brussels).. Last checked against the legal text: 2026-08-19.
Bulgaria
When you need a building permit
For new construction, conversion and change of use, a building permit (razreshenie za stroezh) is required, issued by the municipal architect. After completion, a use permit is necessary, colloquially Akt 16 (razreshenie za polzvane). Only with this permit is the building legally habitable, and utility companies activate household tariffs.
What happens with unpermitted construction
A building without an approved project or a valid building permit is an illegal structure (nezakonen stroezh), and the authority may order demolition. For buildings erected before 2003, a legalization path existed subject to conditions. The obligation falls on the owner, so after purchase it passes to the acquirer. Therefore, the buyer should demand the building permit and the use permit (Akt 16).
Basis: The governing statute is the Zakon za ustroystvo na teritoriyata, ZUT.. Last checked against the legal text: 2026-08-19.
Denmark
When you need a building permit
New construction and substantial alterations require a Byggetilladelse (building permit) under the Bygningsreglement (BR18), applied for via the digital portal Byg og Miljø. After completion, an Ibrugtagningstilladelse (occupancy permit) is required, and the building is entered in the BBR-Register (Building and Dwelling Register).
What happens with unpermitted construction
An ulovligt byggeri (unlawful construction) may be formally illegal, meaning it was built without a permit, or materially illegal, meaning it violates building regulations. The municipality will then demand lovliggørelse (legalisation), either legally through a subsequent permit or physically through demolition. Many owners only discover unlawful construction when selling; an incorrect BBR-Register entry is a warning signal.
Basis: Building Act (byggeloven) and Planning Act (planloven).. Last checked against the legal text: 2026-08-19.
Estonia
When you need a building permit
Estonia has a tiered system: larger developments require an Ehitusluba (building permit), smaller ones require a construction notice, and very small structures are exempt. Use may only commence after completion once a Kasutusluba (permit for use) has been obtained. The entire process is administered through the building register, the ehitisregister (EHR).
What happens with unpermitted construction
A structure built without a permit or without a Kasutusluba may be challenged by the municipality. The municipality may demand demolition or subsequent registration and legalization. Since 2026, registering older, unapproved structures is less expensive, because the previous fee no longer applies. This obligation rests with the owner, meaning that after a purchase it passes to the acquirer.
Basis: The legal basis is the Ehitusseadustik.. Last checked against the legal text: 2026-08-19.
Finland
When you need a building permit
Under the new building law of 2025, a single rakennuslupa (building permit) consolidates the previously separate types of permits. Upon completion, the final inspection (loppukatselmus) concludes the procedure and permits use.
What happens with unpermitted construction
If a building is constructed without a permit, the building supervision authority (rakennusvalvonta) may order rectification or demolition and impose a penalty payment (uhkasakko). The obligation falls on the owner, so after a purchase it falls on the acquirer.
Basis: The legal basis is the rakentamislaki, Act No. 751/2023, which has applied since 2025, and the former maankäyttö- ja rakennuslaki.. Last checked against the legal text: 2026-08-19.
France
When you need a building permit
New buildings exceeding 20 m² in ground or floor area require a Permis de construire (building permit), while those between 5 m² and 20 m² require a Déclaration préalable (prior declaration). Upon completion, the Déclaration attestant l'achèvement et la conformité des travaux (DAACT, declaration attesting completion and conformity of the works) must be submitted.
What happens with unpermitted construction
Construction without the required permit is an offense under the Code de l'urbanisme. The offense may be prosecuted for up to ten years and carries demolition and a fine of up to 6,000 Euro per square meter. Subsequent regularization by filing a building application is possible, but not guaranteed.
Basis: Code de l'urbanisme, Art. L. 421-1 regarding the permit requirement; development in accordance with the Plan Local d'Urbanisme.. Last checked against the legal text: 2026-08-19.
Greece
When you need a building permit
New construction, major alterations, and changes of use require a building permit (oikodomiki adeia), now issued electronically as an e-adeia. For smaller works, a lower-tier permit or a notification is sufficient. The technical requirements are laid down in the New Building Regulation.
What happens with unpermitted construction
An afthaireto (unauthorized construction) or any execution deviating from the permit is prohibited. On sale, an engineer must declare in the notarial deed that no unauthorized works exist; without this declaration, the notarial deed cannot be executed. Older violations may be regularized (taktopoiisi) within time limits and upon payment of a fine, otherwise demolition is threatened. This obligation rests with the owner, and after the purchase with the acquirer.
Basis: Law 4495/2017 on the control and protection of the built environment (unauthorized construction and building permits) and Law 4067/2012 (New Building Regulation, NOK).. Last checked against the legal text: 2026-08-19.
Ireland
When you need a building permit
Two separate systems, as in the United Kingdom: planning permission from the local authority decides WHETHER something may be built, the Building Regulations decide HOW it must be built. Smaller projects count as exempted development, free of a permit. Since a reform that took effect on 27 July 2026, that now includes an extension of up to 45 square metres behind the house, up from the previous 40, plus new exemptions for dormer roof extensions, a separate outbuilding of up to 45 square metres, and an extra dwelling unit of at least 32 square metres created by subdividing the main house. On completion, a Certificate of Compliance from the architect or engineer confirms that both sets of rules were met.
What happens with unpermitted construction
THE DECISIVE POINT IN IRELAND is the seven-year rule, and how often it gets misread. Under section 157(4) of the Planning and Development Act 2000, the authority can no longer issue an enforcement notice, or seek an injunction under section 160, once seven years have passed since the development began. That does not make the structure lawful: it becomes unauthorised but immune, tolerated rather than approved. The consequence still lands on the buyer, because a sale or a mortgage application requires proof of permission, and without it the bank will not release funds. The way out is retention permission, approval granted after the fact. Within the seven years, building without permission is also a criminal offence under section 151.
Basis: Set out in the Planning and Development Act 2000 (section 151 for the criminal offence, section 157(4) for the seven-year rule, section 160 for a court injunction), the Building Control Act 1990 and the Building Regulations made under it.. Last checked against the legal text: 2026-08-18.
Iceland
When you need a building permit
A permit is required under Article 9 of the Buildings Act (Lög um mannvirki nr. 160/2010, Mannvirkjalög) for excavation, construction, demolition, relocation, structural or utility changes, and any change of use, appearance, or form, issued by the municipality's byggingarfulltrúi, or in special cases by the state authority. Conditions for issue include conformity with the land-use plan, paid fees, and a signed declaration of liability from the building supervisor (Article 13). The permit lapses if work has not begun within 12 months (Article 14). Small structures up to 15 square metres and 2.5 metres in ridge height are exempt (Building Regulation 112/2012, clause 2.3.5), and anything closer than 3.0 metres to a neighbouring plot needs that neighbour's consent.
What happens with unpermitted construction
For unauthorised construction, a concept the statute itself never names but practice and case law call óleyfisframkvæmd, the authority can immediately halt the work and order the structure closed (Article 55(1)). It can also require the unlawful structure to be removed, the ground restored, or its use stopped; if the owner fails to comply, the authority carries the work out at the owner's expense (Article 55(2) and (4)). The municipality or the state then holds both a claim for reimbursement AND a statutory lien on the building, its materials, and the plot itself (Article 55(5)). Article 56 adds daily coercive fines of up to 500,000 krónur. This removal and coercive-fine liability follows the CURRENT owner, regardless of who originally built the structure: in a Reykjavík case, the 2019 owner had to answer for an outbuilding put up without permission back in 1946, not the long-dead original builder. There is no clearly settled statutory time limit on the removal power itself. The appeals board UUA nonetheless quashed a demolition order for that same 79-year-old outbuilding in September 2025, reasoning that decades of official inaction made enforcement disproportionate, a case-by-case fairness test rather than a fixed deadline. Retroactive legalisation has no express basis in the statute. For the unauthorised act itself, Article 57a threatens administrative fines of 10,000 to 10,000,000 krónur against individuals, and Article 58 adds a fine or imprisonment of up to two years.
Basis: Buildings Act (Lög um mannvirki nr. 160/2010, Mannvirkjalög): Articles 9, 13 and 14 for the permit requirement, Article 55 for removal and the statutory lien, Article 56 for coercive fines, Article 57a for administrative fines, Article 57c for their five-year limitation period, and Article 58 for criminal liability; Building Regulation (Byggingarreglugerð) nr. 112/2012; Planning Act (Skipulagslög) nr. 123/2010, Article 37.. Last checked against the legal text: 2026-08-19.
Italy
When you need a building permit
New construction and major alterations require the Permesso di costruire (building permit), while minor works are covered by the SCIA (Segnalazione Certificata di Inizio Attività, certified notice of commencement of activity). After completion, the Agibilità (certificate of habitability) confirms that the property is fit for occupation.
What happens with unpermitted construction
An abuso edilizio, meaning construction carried out without a permit or in deviation from an issued permit, carries serious consequences in Italy. The seller must attach the building permit and all subsequent approvals to the purchase contract. If urban planning conformity is lacking, the contract is void under Art. 46 DPR 380/2001 (nullità urbanistica, planning nullity), the buyer cannot obtain a mortgage, and fines and demolition orders may be imposed.
Basis: Testo Unico dell'Edilizia (DPR 380/2001); Art. 46 provides for the nullity of purchase contracts lacking building conformity.. Last checked against the legal text: 2026-08-19.
Croatia
When you need a building permit
New construction, major extensions and extensive conversions require a Građevinska dozvola (building permit). Only upon completion does the Uporabna dozvola (use permit) authorise use.
What happens with unpermitted construction
Bespravna gradnja (illegal construction) is widespread in Croatia. The new construction law provides for fines of EUR 20,000 to EUR 30,000 from 2026 and makes illegal construction a criminal offence. For buildings completed before 21 June 2011, permanent legalisation remains possible: the rješenje o izvedenom stanju (decision on the as-built condition) then has the same effect as a use permit. Without legalisation, demolition is threatened.
Basis: The legal framework is set by the Zakon o gradnji and the Zakon o postupanju s nezakonito izgrađenim zgradama.. Last checked against the legal text: 2026-08-19.
Latvia
When you need a building permit
New construction and substantial alterations require a Būvatļauja (building permit). Since 2020, all construction documentation is filed electronically through the building information system BIS. Upon completion, the akts par būves pieņemšanu ekspluatācijā (act of acceptance for use) is required.
What happens with unpermitted construction
A patvaļīga būvniecība (unauthorised construction) may compel the būvvalde (building authority) to order demolition or legalisation. In addition, an increased land tax is levied on illegal structures. The obligation falls on the owner, so after purchase it passes to the acquirer.
Basis: Būvniecības likums. Last checked against the legal text: 2026-08-19.
Liechtenstein
When you need a building permit
A building permit is required under Article 72 of the Building Act (BauG, LR 701.0) for construction, alteration and demolition, for a change of use even without physical alterations, for private parking spaces, for building services installations above 3 kW of thermal output, and for larger changes to ground level. The authority decides within two months as a rule (Article 79), though that deadline carries no legal consequence of its own.
What happens with unpermitted construction
Where a building is put up without the required permit, or departs from it, Article 94 orders a stop to the work and requires restoration of the lawful state within a set deadline, enforced at the owner's expense if necessary. That restoration order is suspended if a retroactive permit application is filed within six weeks of being asked to do so. Under Article 95, the authority's power to ORDER removal lapses after 20 years from construction, and its power to ENFORCE an already final removal order lapses after 10 years from that finality. Where safety or health is at risk, no time limit applies at all. Once time-barred, the building is treated as if it had been approved. Article 99 threatens a fine of up to 100,000 francs, or imprisonment of up to one year in default, for intentionally building without permission, with its own shorter three-year limitation period for that prosecution. According to the official commentary on the Building Act, the restoration obligation itself passes to a legal successor, so a buyer can inherit it.
Basis: Building Act (Baugesetz, BauG) of 11 December 2008, LGBl. 2009 No. 44, LR 701.0: Articles 47 and 72 for setbacks and the permit requirement, Article 94 for restoration of the lawful state, Article 95 for the limitation periods, and Article 99 for the penal provisions.. Last checked against the legal text: 2026-08-19.
Lithuania
When you need a building permit
New construction, conversion, and demolition require a Statybos leidimas (building permit); exemptions apply to simple projects. Upon completion, the Statybos užbaigimo aktas (completion certificate) closes the procedure.
What happens with unpermitted construction
The owner must demolish a savavališka statyba (unauthorized building). If the owner does not comply, the construction inspectorate (VTPSI) orders compulsory demolition. Legalisation is possible subject to conditions. The obligation lies with the owner, so after a purchase it falls to the acquirer.
Basis: The legal basis is the Statybos įstatymas, which governs construction, and the Teritorijų planavimo įstatymas, which governs territorial planning.. Last checked against the legal text: 2026-08-19.
Luxembourg
When you need a building permit
Any new construction, conversion, or demolition requires an Autorisation de bâtir (building permit), issued by the mayor of the commune. The project is checked for conformity with the Plan d'Aménagement Général (PAG) and the Plan d'Aménagement Particulier (PAP).
What happens with unpermitted construction
If a building erected without a permit cannot be regularised retrospectively because it violates the PAG, the PAP, or the building regulations, the commune may order its demolition and reinstatement at the owner's expense. Such a structure must be disclosed on sale and may block the purchase or reduce the price.
Basis: The legal basis is the loi concernant l'aménagement communal et le développement urbain, together with the applicable communal building regulations.. Last checked against the legal text: 2026-08-19.
Malta
When you need a building permit
Every development requires a development permission from the Planning Authority. Before construction begins, a commencement notice must be submitted. The Building and Construction Authority supervises the execution of the works.
What happens with unpermitted construction
The Planning Authority pursues illegal development through inspections and enforcement proceedings, and may order fines and removal. The buyer should request the Compliance Certificate, which confirms compliance with the permission. The obligation falls on the owner. After the purchase, it therefore falls on the acquirer.
Basis: Development Planning Act (Cap. 552) and Building and Construction Authority Act (Cap. 623). Last checked against the legal text: 2026-08-19.
Netherlands
When you need a building permit
Construction and change of use require the Omgevingsvergunning (environmental permit). Since the Omgevingswet 2024, this is applied for through a single digital procedure, the DSO. Some small projects are vergunningsvrij (permit-free).
What happens with unpermitted construction
If someone builds without or in deviation from the Omgevingsvergunning, the municipality may intervene through handhaving (enforcement): by imposing a last onder dwangsom (penalty payment order) ranging from several hundred to over 10,000 euros, by carrying out the work itself at the owner's expense, or in serious cases by ordering demolition. The permit is tied to the property, so the new owner is also liable for violations.
Basis: The statutory basis is the Omgevingswet, in force since 2024, and the Besluit bouwwerken leefomgeving (Bbl).. Last checked against the legal text: 2026-08-19.
Norway
When you need a building permit
New construction and material alterations require a Byggetillatelse (building permit), often divided into a rammetillatelse (framework permit) and an igangsettingstillatelse (commencement permit). Before the building may be used, a Ferdigattest (final completion certificate) or at least a midlertidig brukstillatelse (temporary occupancy permit) is required.
What happens with unpermitted construction
In the case of an ulovlig byggverk (unlawful structure, that is, construction without a permit or without a Ferdigattest), the municipality may issue a pålegg om retting (order for rectification) or an order for demolition, coupled with a tvangsmulkt (enforcement fine) and an overtredelsesgebyr (infringement fine). The obligation attaches to the owner, so after a purchase it falls on the acquirer.
Basis: plan- og bygningsloven, chapter on unlawful construction works.. Last checked against the legal text: 2026-08-19.
Poland
When you need a building permit
For new construction and larger projects, a Pozwolenie na budowę (building permit) is required; for smaller projects, a Zgłoszenie (notification) suffices. Single-family houses are partly exempt from permits following the reform. Upon completion, a Pozwolenie na użytkowanie (occupancy permit) or a completion notice is required.
What happens with unpermitted construction
In the case of a samowola budowlana (unauthorised construction), the nadzór budowlany (building supervision authority) may order a stop to construction, an often substantial legalisation fee, or demolition. The violation does not become time-barred. The obligation to legalise rests with the respective owner, so after purchase it falls on the acquirer.
Basis: The legal basis is the Prawo budowlane (Polish Construction Law) and the ustawa o planowaniu i zagospodarowaniu przestrzennym (Polish Spatial Planning and Management Act).. Last checked against the legal text: 2026-08-19.
Portugal
When you need a building permit
Construction works require a Licença de construção (construction licence) or a comunicação prévia (prior notification). For the purchase, the decisive document is the Licença de utilização (licence of use), which certifies the approved use.
What happens with unpermitted construction
Building without a permit, obra ilegal (illegal construction), can result in fines from 500 to 200,000 euros, a demolition order at the owner's expense, and criminal liability. The Câmara Municipal (municipal council) has ten years to take action. Since the Simplex Urbanístico reform, the buyer bears responsibility after registration in the land registry.
Basis: The governing law on urbanisation and construction is the Regime Jurídico da Urbanização e Edificação, RJUE, Decreto-Lei 555/99.. Last checked against the legal text: 2026-08-19.
Romania
When you need a building permit
First, a certificat de urbanism (urban planning certificate) is required, which establishes the conditions. Then the autorizatie de construire (building permit) is needed. Upon completion, a proces-verbal de receptie (final acceptance report) closes the procedure.
What happens with unpermitted construction
Building without a permit or deviating from it incurs fines and can result in desfiintare (demolition). Under Art. 56 of Legea nr. 350/2001, a certificat de urbanism may not be used to legalise a structure that was erected without a permit. The owner is subject to this obligation, so after a purchase it passes to the buyer.
Basis: The applicable statutes are Legea nr. 50/1991 and Legea nr. 350/2001.. Last checked against the legal text: 2026-08-19.
Sweden
When you need a building permit
New construction and substantial alterations require a Bygglov (building permit), while smaller projects require an anmälan (notification). Construction may begin once the Startbesked (commencement notice) has been issued. Only the slutbesked (final inspection certificate) allows the building to be taken into use.
What happens with unpermitted construction
A svartbygge (unauthorised construction) may trigger a Byggsanktionsavgift (building sanction fee) of up to 50 prisbasbelopp (price base amounts), which in 2026 corresponds to roughly SEK 2.96 million, and may also lead to a demolition order. The buyer should note that the sanction fee is levied against the property owner at the time of the decision, not against the builder. Consequently, a purchaser can become liable for payment.
Basis: The legal basis is formed by the Plan- och bygglagen (PBL, SFS 2010:900) and the building regulations issued by Boverket.. Last checked against the legal text: 2026-08-19.
Serbia
When you need a building permit
New construction and major interventions require a building permit (gradjevinska dozvola), issued in a unified electronic procedure. After completion, a use permit (upotrebna dozvola) is required: the building may not be used until this permit is in place.
What happens with unpermitted construction
Serbia has millions of buildings constructed without permits (nelegalna gradnja). A separate legalization procedure (ozakonjenje) applies to them. Without legalization, demolition is threatened, and the property is difficult to mortgage or register. The obligation falls on the owner, meaning the acquirer after purchase, so the buyer should verify whether the building and use permits exist or legalization is complete.
Basis: The legal basis is formed by the Zakon o planiranju i izgradnji and the Zakon o ozakonjenju objekata.. Last checked against the legal text: 2026-08-19.
Slovakia
When you need a building permit
Under the new Stavebný zákon (Act No. 25/2025 Z. z.), in force since 1 April 2025, permission is granted in a single combined procedure (konanie o stavebnom zámere) that merges what used to be two separate decisions, on siting and on the building itself. What used to be called the kolaudácia is now formally the review of fitness for use (preskúmanie spôsobilosti stavby na užívanie), ending in a certificate of occupancy (kolaudačné osvedčenie).
What happens with unpermitted construction
THE DECISIVE CHANGE IN SLOVAKIA is that retroactive legalisation (dodatočné povolenie) of a čierna stavba, an unauthorised building, no longer exists for anything built from 1 April 2025 onward. Once such a building is identified, the only route left is a demolition order (odstránenie stavby), enforced at the owner's expense if not carried out voluntarily. For older unauthorised buildings, put up between 1990 and 31 March 2025, a transitional window runs until 31 March 2029, offering a simplified route to retroactive recognition. That transitional rule is itself being challenged before the Constitutional Court since December 2025, with no ruling yet. There is no time limit on enforcement action, and the obligation follows the property to whoever owns it, meaning a buyer after purchase.
Basis: Building Act (Stavebný zákon, Act No. 25/2025 Z. z.), in force since 1 April 2025, which replaced the previously planned Act on Construction (zákon o výstavbe) before that one ever took effect.. Last checked against the legal text: 2026-08-19.
Slovenia
When you need a building permit
New construction and substantial alterations require a Gradbeno dovoljenje (building permit). Only after completion does the Uporabno dovoljenje (use permit) authorize use.
What happens with unpermitted construction
The building act distinguishes between a nelegalni objekt (structure erected without a building permit) and a neskladni objekt (structure deviating from the permit). The gradbena inšpekcija (building inspectorate) may order odstranitev (removal). The obligation falls on the owner, and therefore on the acquirer after a purchase.
Basis: The legal basis is formed by the Gradbeni zakon, GZ-1, and the Zakon o urejanju prostora.. Last checked against the legal text: 2026-08-19.
Spain
When you need a building permit
Building work needs a Licencia de obras from the municipality; once it is finished, a Licencia de primera ocupación or a Cédula de habitabilidad certifies that the property may actually be lived in and gets connected to water and electricity.
What happens with unpermitted construction
THE DECISIVE CONCEPT IN SPAIN is fuera de ordenación. A building put up without the required licence (obra ilegal) can be fined, refused a utility connection, and hit with a demolition order that follows the property to a later buyer. How long the authority has to act depends on the region and the severity of the offence: from as little as one year for minor infractions up to 15 years for the most serious ones in Galicia, while Andalusia raised its period from four to six years in a 2012 reform. Madrid applies no limitation period at all to green, open, or public land. Once the period has run out, the building does not become legal. It becomes fuera de ordenación instead: tolerated, but with no route to full legalisation, and with restrictions on renovation and extension. An AFO certificate (Asimilado Fuera de Ordenación) can confirm that status, which matters at resale because a mortgage lender will want to see it.
Basis: Land Act (Ley de Suelo, Real Decreto Legislativo 7/2015) and the planning laws of the individual Comunidades Autónomas, including Andalusia's 2012 reform of its limitation periods.. Last checked against the legal text: 2026-08-19.
Czechia
When you need a building permit
Since the new building law of 2024, approval runs in a single digital procedure. New construction and larger projects require a Stavební povolení (building permit), while simple structures follow an accelerated procedure. After completion, use is only permitted once a Kolaudační povolení (occupancy permit) or a Kolaudační souhlas (occupancy consent) has been issued.
What happens with unpermitted construction
If a structure is a černá stavba (building erected without approval), the Stavební úřad (building authority) may order its odstranění stavby (removal of the structure). The dodatečné povolení (retrospective approval) has been stricter since the reform. The obligation rests with the respective owner, so after a purchase it passes to the acquirer.
Basis: stavební záon, Gesetz Nr. 283/2021 Sb., in Kraft seit 2024. Last checked against the legal text: 2026-08-19.
Hungary
When you need a building permit
New construction and larger projects require an Építési engedély (building permit), applied for through the electronic system. After completion, use is only permitted once the Használatbavételi engedély (use permit) has been obtained.
What happens with unpermitted construction
In the case of a szabálytalan építkezés (construction without or deviating from the permit), the building authority may intervene within ten years of completion. A subsequent permit (fennmaradási engedély) is possible under certain conditions, but it is subject to a building fine (építésügyi bírság); the fine may be waived if the unlawful construction is demolished within the prescribed deadline.
Basis: Act No. LXXVIII/1997 on the protection of the built environment (épített környezet) and the related building regulations.. Last checked against the legal text: 2026-08-19.
United Kingdom
When you need a building permit
Two separate systems: Planning permission determines whether construction is permitted, and Building Regulations approval governs how safely building work must be carried out. After the works, a Building Regulations completion certificate confirms compliance.
What happens with unpermitted construction
If development has not been approved, the Local Planning Authority may issue an enforcement notice, which can require demolition. Enforcement action must be taken within four years for building works and within ten years for changes of use. Thereafter, a Lawful Development Certificate can confirm lawfulness. The absence of a Building Regulations completion certificate is a buyer risk.
Basis: The statutory basis is the Town and Country Planning Act 1990 and the Building Regulations.. Last checked against the legal text: 2026-08-19.
Cyprus
When you need a building permit
Two steps are required in Cyprus: first planning permission, then the building permit. Upon completion, the authority issues the certificate of approval, which forms the basis for the separate title deed.
What happens with unpermitted construction
Where building work is carried out without permission or deviates from the permission granted, the separate title deed will be missing in the end, and the authority can require removal. In Cyprus especially, a missing or delayed title deed is a frequent hidden defect. The buyer should check whether a separate title exists. The obligation falls on the owner, and after purchase therefore on the acquirer.
Basis: Streets and Buildings Regulation Law, Cap. 96 (building permit), and Town and Country Planning Law, Gesetz 90/1972 (planning permission). Last checked against the legal text: 2026-08-19.
Frequently Asked Questions
Can it be approved after the fact?
Often yes, but it takes time and money, and only works if the structure would be permitted under today's rules at all. If it would not, removal is the only option left.
Is the seller liable for it?
If they knew and stayed quiet, yes, and an agreed exclusion of liability does not change that. The problem is proving it. That is why the check belongs before you sign, not after.
More
Ready to have a property checked honestly?
In a few minutes you have a complete, conservative report with a valuation PDF. No appointment, no paperwork.
Stay in the loop
We write rarely and only when it is genuinely useful: new features, a sober look at the market, honest advice on buying, selling and renting.