What is a building permit and when do you need one
A building permit is the primary legal authorization that allows construction work to proceed in Greece. It is issued by competent authorities (municipality, local government, or the Ministry of Environment) and ensures that your project complies with building codes, zoning regulations, and local planning rules. Most significant structural changes, new builds, and renovations require a permit.
Work that requires a building permit includes:
- New constructions (residential, commercial, industrial facilities)
- Additions or extensions to existing buildings
- Change of building use (for example, residential to office)
- Renovations involving structural changes or change of residential status
- Civil engineering projects (roads, bridges, water tanks)
By contrast, some minor works do not require a permit, such as interior repairs or simple surface restoration.
The three categories of building permits
Law 4495/2017 classifies permitted work into three categories based on project complexity and scale. Each has different document requirements, study scope, and processing timelines.
Category 1: Simple works
Simple works include repairs and renovations without structural changes, such as interior finishing or mechanical and electrical upgrades to existing buildings. These require straightforward documentation and move through review quickly. Typical approval time is 20-30 days.
Category 2: Moderate complexity
Category 2 covers additions, change of use, and renovations with limited structural intervention. These require more detailed studies (architectural, structural, energy) and closer government review. Processing typically takes 40-60 days under normal conditions.
Category 3: Complex projects
Complex projects include new constructions, large extensions, and major spatial reorganizations. They require complete multidisciplinary studies, thorough review, and coordination across agencies. Processing can exceed 90 days or longer.
Required documents and studies
A building permit cannot be issued without a complete set of supporting documents and technical studies. These verify legality, safety, and compliance with applicable standards.
Key documents
- Proof of property right: Evidence of ownership or legal right to use the land
- Property identification number: Registration in the National Cadastre (EKXA) with official property number
- Electronic Building Identity (EBI): Technical record of the existing building
- Engineer certification: Official commitment from the supervising engineer responsible for oversight
- Topographic survey: Precise map of the property and surrounding area with coordinates
Technical studies
Depending on the project type, the following studies are typically required:
- Architectural study: Floor plans, sections, elevations, and detailed drawings of the building
- Structural study: Analysis of load-bearing capacity and safety of the building
- MEP systems study: Design of electrical, plumbing, and HVAC (heating, cooling, ventilation)
- Energy performance study (KENAK): Assessment of building energy efficiency per European standards
- Accessibility study: Verification of accessibility for persons with disabilities (where applicable)
For preparation of these studies, work with a qualified engineer who can certify compliance with all applicable regulations.
How e-Adeies works: Step by step
e-Adeies is the official electronic platform for building permit applications in Greece, operated by the TEE (Technical Chamber of Greece) and the Ministry of Environment. As of this writing, it is the authorized system for all building permit submissions.
1. Prepare your documents
Start by consulting with an engineer to assess your project. Gather property documents (cadastral records, building identity certificate, survey). Have your engineer prepare all required studies simultaneously.
2. Register on e-Adeies
The engineer or applicant creates an account with valid identification. The system requires electronic authentication (bank credentials, e-Banking, or other approved method).
3. Create your application
Start a new application, select the work category and project type, and enter property and applicant details into the system.
4. Upload documents and studies
All documents and studies are uploaded digitally (PDF or compatible format). The system automatically validates file format and size.
5. Submit your application
Once complete, you electronically submit the application. The system immediately issues a receipt and provides a reference number for tracking.
6. Government review
The competent authority (municipality or relevant agency) reviews documents and studies for compliance with local regulations and standards. If clarifications are needed, they request additional information.
7. Issuance or rejection
If all items are in order, the permit is issued and notified in the system. If problems are found, the application is rejected with reasons noted. If corrections are needed, you receive written notice.
How long does the permit process take
Processing time varies and is affected by several factors:
- Permit category: Category 1 (simple) is faster (20-30 days), Category 3 (complex) is slower (90+ days)
- Document completeness: Missing documents or study errors significantly extend timelines
- Multi-agency review: Some projects require approval from archaeology or environmental agencies
- Government workload: Peak periods can lengthen processing windows
- Clarification requests: If authorities ask for additional information, processing pauses
As a general rule, a Category 2 permit with complete documentation takes 6-8 weeks from submission to final approval.
What factors affect the cost
There is no standard cost for all permits. Many variables influence the total expense:
- Permit category: Category 1 costs less than Category 3 due to reduced complexity and review
- Project scope and size: Larger projects require more detailed studies and extended review
- Number and complexity of studies: Each discipline (architecture, structure, MEP, energy) has its own fee
- Local government fees: Some municipalities charge issuance fees or administrative costs
- Supervising engineer fee: Professional fees vary based on project scope
- Electronic documentation: Additional electronic certifications or declarations may apply
In general, higher complexity means higher costs. For an accurate estimate, consult your engineer and local authorities.
Works that do not require a building permit
Although most construction work requires authorization, some categories are exempt or fall under special small-scale status:
- Interior repairs and restoration without structural changes
- Mechanical and electrical upgrades to existing buildings (no structural work)
- Painting, surface finishes, and interior decoration
- Installation of minor elements or enclosures in small spaces
- Other works under small-scale or minor works exemptions per Greek law
For details on exempt or small-scale works, see our guide on small-scale building permits.
Permit validity, renewal, and modifications
Building permits have a limited validity period. As of this writing, the standard validity is 3 years from issuance. If work does not start or is not completed within this period, the permit expires.
Renewal (extension): The validity period can be extended for 1-2 additional years with a new application and justification for the delay.
Modification/Amendment: If work begins but the design changes significantly, you must request a permit amendment or revision. Depending on the nature and scale of changes, some modifications can proceed without a full new permit, while others require a complete revision application.
How to check an existing property's permit before you buy
Verifying a property someone else built is a different exercise from applying for a permit yourself. e-Adeies is the platform engineers use to submit and track applications, so the online part of the check runs through a licensed engineer acting for you: a permit filed through the platform carries a tracking number your engineer can look up against the file the seller provides.
The sequence is straightforward. Ask the seller or their engineer for the building permit and the approved drawings, have your own engineer compare those drawings against what is actually built on site, then ask for the electronic building identity and its completeness certificate. The building identity is the most direct route, because it consolidates a property's permits, plans and any legalisation records into a single digital file, and it is mandatory whenever a property is sold, gifted or transferred.
The completeness certificate is where the due diligence actually lands. An engineer issues it only once the building identity file has been verified, and the transfer itself requires it, so a seller who cannot produce one has something unresolved on the property. Most often that something is unauthorised construction.
When a property already has unauthorised works
A permit governs what you are allowed to build. Where something has already been built without one, or a space is being used differently from what the permit approved, that is a separate procedure with its own declaration steps, deadlines and fines. It matters most at the point of sale, because the electronic building identity file cannot be completed while the issue is outstanding. Our guide on legalising unauthorised construction sets out the categories under Law 4495/2017, what determines the fine, and how an outstanding case affects a property transfer.
Frequently asked questions
How much does a building permit cost in Greece?
There is no fixed price. Costs depend on the permit category, project type and size, required studies (architectural, structural, MEP, energy), and the supervising engineer fee. Complex projects cost more than simple renovations. For an accurate quote, contact the Premier Construction team.
How long does it take to get a building permit in Greece?
Category 1 (simple works) typically takes 20-30 days. Category 2 (moderate complexity) takes 40-60 days. Category 3 (complex projects) can exceed 90 days. Incomplete documentation or requests for clarification extend timelines.
What is e-Adeies and how does it work?
e-Adeies is the official electronic platform for submitting building permit applications in Greece, overseen by the TEE (Technical Chamber) and Ministry of Environment. All applications are submitted digitally, providing transparency and faster processing. You receive an immediate receipt and tracking number.
What are the permit categories under Greek law (Law 4495/2017)?
Category 1 covers simple works (repairs and renovations without structural changes). Category 2 covers moderate complexity (additions, change of use). Category 3 covers complex projects (new constructions, major extensions). Each category has different requirements and timeframes.
What works do not require a building permit?
Minor repairs and renovations without structural changes typically do not require a permit, including interior finishing, surface restoration, mechanical and electrical upgrades to existing buildings, painting, and decoration. To confirm whether your specific work requires authorization, consult your local municipality or a qualified engineer.
How long is a building permit valid?
A building permit is typically valid for 3 years from issuance. If work does not start or is not completed within this period, the permit expires. However, the validity can be extended for 1-2 additional years with a new renewal application and justification for the delay.
Do I need an engineer for a building permit?
Yes, a qualified engineer is essential for preparing required studies and managing the permit process. The engineer prepares architectural, structural, and MEP designs, handles the electronic submission via e-Adeies, and oversees compliance throughout construction.
How do I check whether a property in Greece has a valid building permit?
Ask the seller or their engineer for the building permit file and the approved drawings, then have your own engineer compare them against what is actually built on site. The electronic building identity is the most direct route, because it consolidates a property’s permits, plans and any legalisation records into a single digital file, and it is mandatory whenever a property is sold, gifted or transferred. Permits submitted through e-Adeies also carry a tracking number your engineer can check.
What documents should I ask for before buying a property in Greece?
Request the building permit together with the approved architectural drawings, the electronic building identity and its completeness certificate, and confirmation that no unauthorised works or undeclared changes of use are outstanding. The completeness certificate is issued by an engineer once the building identity file has been verified, and the transfer itself requires it, so a seller who cannot produce it has an unresolved issue.
What if a property has unauthorised construction?
Unauthorised works and undeclared changes of use have to be declared and registered through a licensed engineer under Law 4495/2017, and a fine may apply depending on the category of the work. Until that is settled the electronic building identity file cannot be completed, so the completeness certificate a transfer requires cannot be issued either. Clarifying the position before you commit to a purchase is considerably cheaper than discovering it afterwards.
Sources: National Registry of Procedures (mitos.gov.gr) · Law 4495/2017 (kodiko.gr)
Written and reviewed by the engineering team at Premier Construction. Last updated: 24 July 2026. This article is general information and does not substitute for technical or legal advice for a specific property. Meet the team.