Unauthorised Construction in Greece and the Engineer's Certificate: The Regularisation Law, How to Identify It and the Risk to the Buyer

1What counts as unauthorised construction in Greece?

Unauthorised construction (αυθαίρετο) is any construction carried out without a building permit, beyond what the permit allows, in breach of planning rules, or on the basis of a permit that was annulled. The definition appears in Article 81 of Law 4495/2017. The law grants limited tolerance: a deviation of up to 2% in the external dimensions is not considered a violation.

In practice, in the Greek market unauthorised construction is a very widespread phenomenon and not a rare one. According to reports in the Greek press, more than 1.7 million property owners have already regularised violations in Categories 1 to 4. In the apartments and houses that Israelis buy, the typical violations are the enclosure of a semi-open balcony (ημιυπαίθριος) into a room, the conversion of a storeroom or basement into living space, the addition of a room on the roof, large pergolas and internal layout changes that were not updated in the plans.

2Why is unauthorised construction the buyer's problem and not only the seller's?

Because the law affects the transaction itself. Article 82 of Law 4495/2017 prohibits transactions in properties containing unregularised violations. Article 83 requires that every transfer deed attach an engineer's certificate and an owner's declaration on the state of construction. Where regularised violations do not appear in the permit plans, the deed must set out the regularisation data and attach the plans from the system, and if this is not done, the deed is void.

Beyond the validity of the transaction there are also economic consequences. A property with an unregularised violation may be exposed to fines and enforcement proceedings. It is hard to finance with a mortgage, and hard to sell later, because the next buyer will demand the same certificate. Someone who buys a property "with a small problem that will be sorted out later" is in effect buying the problem.

3What are the five categories of violations under Law 4495/2017?

Article 96 of the law divides violations into five categories. The category determines whether the violation can be regularised and at what cost:

Regularisation under the law applies to violations built before 28.7.2011. A violation built after that date does not fall within the regularisation track, and is exposed to full enforcement.

4Until when can unauthorised construction be regularised in Greece?

As of October 2026, the regularisation deadlines under Article 102 of Law 4495/2017 were extended from 31.3.2026 to 31.3.2028, in Article 43 of Law 5270/2026. The same article also extended the deadline for submitting the building's electronic identity for Type I buildings, to 1.2.2028.

For Category 5 the picture is different. According to the answer of the responsible deputy minister in the Greek parliament in February 2026, regularisation of Category 5 lapsed in 2020, and the exceptional window for banks and investment funds ended on 31.12.2025 with no further extension. The minister did not rule out a renewed review within a broad reform, but there is no date for it. A buyer should not build on a future reopening of the track.

5Can you buy a property whose regularisation is still in progress?

Yes, subject to conditions. Under Article 83 of the law a property can be transferred after the fine has been paid in full, or at least 30% of it. In that case the new buyer takes on the duty to complete the procedure, that is, to pay the balance of the fine and submit the missing documents, and this is recorded in the deed. The engineer's certificate must state expressly that 30% of the fine has been paid and that the required documents have been uploaded to the system.

The meaning for the buyer: the balance of the fine and the cost of completing the documents (including structural examinations, where required) pass to him, unless the contract provides otherwise. We therefore require to see the status of the file in the system and the balance of payments. The amount is then deducted from the price or held in escrow until the procedure is completed.

6How do you identify unauthorised construction before buying?

Identification is carried out through a combination of documents and an inspection on site, preferably by an engineer who represents the buyer. The order of review that we recommend:

1. Request the building permit and the approved plans from the seller or from the planning authority, including any permit amendment made since.
2. Compare the plans with the situation on the ground: areas, balconies, roof, basement, internal layout and uses. Every gap is documented in writing.
3. Check whether a regularisation declaration was previously submitted and at what stage it stands: preliminary declaration, final declaration with 30% of the fine, or completed declaration.
4. Classify each violation into a category and estimate the cost of regularisation. If it is a Category 5 violation, stop and reconsider.
5. Check the building's electronic identity where it exists, and the common property in a condominium. Violations in the common property may also have an effect.
6. Obtain the seller's draft engineer's certificate before signing, not on the day of signing. Compare it with your own engineer's findings.

7How is the buyer protected in the contract?

• Condition precedent: completion of the transaction is conditional on a clean engineer's certificate, or on completion of the regularisation at the seller's expense by a defined date.
• A representation and undertaking by the seller that there are no violations beyond those specified in writing, with an obligation to indemnify if additional violations are discovered.
• A price reduction or escrow in the amount of the balance of the fine and the expected costs, where regularisation has not yet been completed.
• A right to cancel and a refund of the deposit if it turns out that the violation is in Category 5, or was built after 28.7.2011.
• Timing: the certificate is valid for two months, so the date of the deed must be coordinated with the date of issue.

8What is the difference between the engineer's certificate and an engineering inspection on behalf of the buyer?

The engineer's certificate under Article 83 is a legal document required in order to sign the deed. It answers one question: whether the property contains unregularised violations. It is usually ordered by the seller, and the engineer is exposed to criminal and disciplinary liability if it is not accurate. An engineering inspection on behalf of the buyer is broader. It also examines the condition of the structure, damp, systems and whether the areas match the price, and also whether the buyer's business plan can be carried out, for example renovation, division or a change of use. The certificate protects the validity of the deed. The independent inspection protects the investment.

In the transactions we accompany, the buyer's engineer receives the seller's draft certificate and confirms in writing that he agrees with the findings. Where there is a disagreement, it is resolved before signing and not after.

9The Israeli aspect: financing, rental and a future sale

An Israeli buyer is affected by unauthorised construction beyond the transaction itself. Bank financing, in Greece or in Israel, is usually conditional on a property that is in order legally and from a planning standpoint. Insurance may be limited. On the day of sale the next buyer will demand a new engineer's certificate, and a violation that was not dealt with will hurt the price or delay the transaction. When we examine a property for a client, we treat violations as a component in the yield calculation, and not as a "technical detail".

10What to do before signing, and how we accompany the process

Before a deposit, we send an independent engineer to check the match between the permit and the property on the ground, and we check the regularisation status in the system. We classify the violations and price the regularisation. In the contract we include conditions precedent, representations, escrow and timing that fits the validity of the certificate. If the picture includes a Category 5 violation or construction done after 2011, we will say so clearly, even if the meaning is walking away from the deal.

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The information in this guide is general in nature and does not constitute legal or tax advice on any specific transaction. Every transaction is assessed on its own facts.