Illegal and Unauthorised Construction in Greece: What Property Buyers Need to Know
Some Greek properties with unauthorised building work can legally transfer where the particular irregularities meet the applicable statutory conditions. Others face serious transfer restrictions. The outcome depends on the works, construction date, location, statutory category and documentary status. A declaration number or partial fine payment alone does not show that every condition has been met or every alteration covered.
Why does 28 July 2011 matter?
The applicable Greek scheme distinguishes older unauthorised works from those completed after a statutory cutoff. Law 5306/2026, Article 383 describes the categories for qualifying works or changes of use completed by 28 July 2011.
A seller's memory is not automatically adequate proof of construction date. The engineer should identify legally relevant supporting evidence such as available official documents and other materials accepted by the applicable procedure.
Works after the cutoff generally fall under a different and stricter framework, subject to particular applicable procedures and exceptions.
What are Categories 1–5?
The codified law defines five distinct categories; this simplified summary is a buyer guide, not a statutory classification:
| Category | Broad description | What to verify |
|---|---|---|
| 1 | Certain qualifying pre-1975 irregularities | Correct date, predominant use and conditions |
| 2 | Certain qualifying pre-1983 irregularities | Construction evidence and statutory terms |
| 3 | Specified minor irregularities | Exact legal definition, not seller's adjective “small” |
| 4 | Qualifying deviations within defined conditions | Technical thresholds, location and documentation |
| 5 | Irregularities outside Categories 1–4 | Special scrutiny; no general new Category 1–4 filing route |
A building can contain more than one irregularity of different types. Do not accept a single category number as a conclusion about every feature.
What is the 2028 regularisation deadline?
The Ministry of Environment's 2026 announcement states that the general deadline for eligible Categories 1–4, involving works completed before 28 July 2011, was extended to 31 March 2028.
That does not establish that any particular property is eligible. Restrictions, statutory requirements and the category-specific treatment matter. It is not a blanket reopening for every Category 5 situation or every post-2011 addition.
The 2026 planning code, Law 5306/2026, codified provisions formerly associated with Law 4495/2017. The September 2026 notarial circular addresses cross-references and transitional platform terminology. Older document citations are not automatically invalid merely because numbering changed.
Regularised and legalised are not necessarily the same
In everyday listings sellers may call any documented irregularity “legalised”. The underlying Greek procedures have different effects.
Νομιμοποίηση may involve a legally available authorising permit. Υπαγωγή / τακτοποίηση can concern inclusion in a statutory scheme under specific conditions, sometimes with different consequences depending on category.
The buyer should ask what act was issued, what construction it covers, and what conditions remain. Words on an advert are not official legal status.
How do statutory declarations work?
The Technical Chamber of Greece's unauthorised-works service concerns the electronic declaration process. A professional identifies the works, investigates age and eligibility, prepares documents, enters the relevant declaration and handles prescribed conditions.
Opening a submission, paying something, uploading required documents, and satisfying the legal conditions must be distinguished.
For qualifying cases, Law 5306/2026, Articles 367–368 set out particular transfer and engineering-certification conditions, including certain circumstances involving payment of at least 30% of a prescribed fine plus required documentation and notarial wording.
It is not correct to say paying 30% automatically makes every unauthorised property transferable. The legal category, exclusions, documents, required wording, and remaining obligations must be established.
The Regularisation Evidence Checklist
Ask an independent engineer to identify:
| Record | Buyer question |
|---|---|
| Original permit and plans | Which works were originally authorised? |
| Date evidence | When was each relevant irregularity created? |
| Submitted declaration | Which statutory scheme and category were used? |
| Technical description and plans | What specific works does the declaration cover? |
| Current declaration status | Is it filed, complete or otherwise legally effective? |
| Fee/fine records | Which obligations have been met and which remain? |
| Additional required studies | Were applicable technical conditions addressed? |
| HTK record | Is the property identity aligned with current building information? |
| Written engineering assessment | What remains open and what is its consequence? |
| Lawyer's advice | Can the intended transaction proceed under applicable law? |
A declaration for an enclosed balcony does not automatically cover an added garden studio. The detailed scope is essential.
Where can regularisation be restricted?
The law imposes location- and circumstance-based exclusions for certain works, including issues involving forest, shoreline, protected archaeological, public or other regulated areas. Article 374 of Law 5306/2026 identifies important exclusions and exceptions.
Do not conclude from a broad designation alone that every structure is unlawful; the exact location, date, legal acts and exemptions matter. But do not assume a coastal or forest-related issue can simply be corrected later.
The TEE Single Digital Map and official forest maps can identify questions, not replace a property-specific legal determination.
Worked example: three different alterations on one holiday home
A fictional island property is offered for €420,000. Its plans show a main house and storage, while the advertisement includes a converted guest studio, enclosed terrace and detached garden building.
The seller provides a declaration for the terrace but not for the other two changes.
| Feature | Initial evidence | Necessary investigation |
|---|---|---|
| Guest studio | Former storage on plans | Was residential use authorised or addressed? |
| Enclosed terrace | Declaration supplied | Does its scope and status cover the enclosure? |
| Detached structure | No relevant document provided | Construction date, location, category, lawful options |
The seller's statement “everything is regularised” is not sufficient. A lawyer and engineer must examine each issue. This is not automatically a reason to withdraw, but it is not a completed due-diligence result.
Fictional example.
How can unverified space distort asking €/m²?
A fictional apartment is marketed at €300,000 for 100 m², including an 18 m² enclosure with unresolved documentation; available plans show 82 m² main residential area.
| Basis | Asking price ratio |
|---|---|
| 100 m² marketed | €3,000/m² |
| 82 m² documented main | About €3,659/m² |
Neither ratio establishes the apartment's true market value. The difference illustrates how the denominator changes a comparison. It does not prove the enclosure is illegal or valueless.
The price-per-square-metre guide explains why asking, transaction and area definitions must be kept distinct.
Does regularisation prove structural safety?
No. A statutory declaration may require specified technical documents and structural studies in particular cases, but does not necessarily constitute a complete building survey.
An engineer should say which structural information was reviewed and whether further investigation of the physical condition is necessary. HTK documentation is a related but separate framework. See Electronic Building Identity.
Who is responsible for outstanding costs?
Do not assume a universal buyer-versus-seller rule for every fee, fine, professional service or physical correction. Contract terms and legal obligations must be examined separately.
Costs may include engineering, drawings, statutory payments, studies or remedial construction. A price discount does not legalise a prohibited structure or resolve a planning restriction.
Where the law allows particular transfers with outstanding obligations, the buyer's lawyer must establish the precise legal conditions and drafting; the buyer must understand what they assume.
Before a deposit: the decision matrix
| Status | What is known | Buyer response |
|---|---|---|
| Visible discrepancy, no documents | Possible issue | Obtain records and professional review |
| Relevant authorisation found | Particular work is documented | Verify scope and consistency |
| Declaration submitted | Procedure exists | Check eligibility, progress and legal effect |
| Possible regularisation, unfinished | Future outcome not confirmed | Clarify required steps, deadlines and protections |
| Material exclusion or unresolved obstacle | Proposed route may not work | Legal advice before any binding commitment |
A helpful professional conclusion is verified within scope / pending / material unresolved issue, backed by sources—not a universal red/green score.
Have your lawyer review the deposit agreement, the treatment of payments and conditions for withdrawal if material technical or legal findings arise.
Frequently asked questions
Can an illegal extension be regularised in 2026?
Some qualifying older works can use applicable statutory procedures. Eligibility depends on date, category, location and required evidence.
Does the 2028 deadline cover Category 5?
Not under the general Categories 1–4 extension. Particular other statutory cases must be separately checked.
Is a declaration number enough?
No. Verify works covered, status, documents and the applicable legal result.
Does an HTK certificate guarantee no illegal work?
No universal guarantee follows. The underlying documents and relevant professional assessment matter.
What buyers should conclude
First identify what was built, when, under which permit or declaration, and what legal conditions have actually been met. A verbal promise or partial payment cannot replace that evidence.
The Greek Property Report conducts independent, buyer-funded research without commission tied to a sale. It is not a substitute for Greek engineering certification, planning approval or legal advice.
Understand the evidence, and what still needs checking
Our methodology explains what independent, buyer-funded research can establish—and what must be verified by a Greek lawyer, engineer or notary.
Independent, buyer-funded research. No brokerage commission or fee contingent on a completed purchase. Not a professional valuation, legal opinion or engineering assessment.