Apartment Subdivision:
Everything you need to know
The market trend is driving the creation of smaller, more efficient housing units (micro-apartments). However, subdividing a property is a complex equation that requires strict legal and urban-planning preparation.
Why do it? The financial incentives
Demand for small apartments (student housing, singles, Airbnb) has skyrocketed. The Rental Yield per square metre is exponentially higher for two 50 m² apartments compared to a single 100 m² unit.
Key Statistic: Subdivision can increase total resale value by up to 30 % and monthly returns by 45 % in urban areas.
Return Comparison (Indicative Data – Athens / Thessaloniki)
The Legal Framework & the Condominium
The biggest obstacle is not urban planning but the Condominium Internal Regulation. The balances here are delicate and often misinterpreted.
⚠ Critical Legal Notice & Case Law
There is a common misinterpretation. Older court decisions held that "the property is mine, I can split it." However, the Supreme Court case law and the modern Law 4495/17 (Article 98) clarify the following:
Physical Subdivision (Planning-level)
If the regulation is silent, case law permits you to internally partition the apartment, provided that load-bearing elements or common areas are not affected.
Legal Subdivision (Notarial)
For the new units to obtain separate millesimal shares and be independently transferable / sellable, an Amendment of the Horizontal Property Deed is required. This requires 100 % consent from all co-owners, unless the original regulation explicitly grants the right to unilateral amendment.
Decision Tree: What does the Regulation say?
Planning Requirements & Construction
For the works to be lawful, the appropriate permit from the Building Authority (YDOM) is needed. The type of permit depends on the scope of the interventions.
Small-Scale Works Approval (EEMK)
Sufficient if the changes are strictly internal (demolishing non-load-bearing walls, new plasterboard partitions) and the façades, common areas (e.g. opening a new door to the stairwell) or shared utilities (central heating) are NOT altered. The budget must also not exceed €25,000. Caution however: Court case law (Administrative Court of Thessaloniki 117/2018) has ruled that subdivision constitutes a radical change of functionality and requires a full Building Permit. Using an EEMK leaves the project legally exposed and vulnerable to annulment if co-owners file a legal challenge.
Full Building Permit
Usually required. Creating a new entrance from the stairwell (alteration of common area), changing windows on the façade, and structural reinforcements all require a full permit. This involves structural checks and a new Energy Performance Certificate (KENAK).
The Parking-Space "Catch"
Subdivision creates a new, independent property. In many municipalities (depending on size and area), this triggers the mandatory parking-space requirement. A parking-space buy-out from the municipality may be required (costing several thousand euros) if no space is available.
Indicative Total-Cost Breakdown
For subdividing a 100 m² apartment (Average: €35,000 – €50,000)
The Ultimate Approvals & Actions Checklist
PHASE 1: CHECKS & PREPARATION
- Review Condominium Regulation (by a Lawyer)
- Engineer Site Inspection (Existing-Legality Check)
- Regularise any Unauthorised Works (Law 4495/17) before anything else
- Collect Signatures (100 % or as the regulation requires if common areas are affected)
PHASE 2: PLANNING & STUDIES
- Architectural Study of the New Layout
- M&E Study (New electricity, water, heating connections)
- Issue Energy Performance Certificate (PEA / KENAK)
- Issue Building Permit / EEMK via e-Adeies
PHASE 3: LEGAL COMPLETION (LEGAL SUBDIVISION ONLY)
- Issue Engineer's Certificate for transfer (Building Identity)
- Notarial Deed: Amendment of Horizontal Property Deed (New millesimal shares)
- Registration at the Land Registry / Mortgage Office (2 new KAEK codes)
- Update E9 Tax Form at the Tax Office (DOY) – Delete old, register 2 new
Frequently Asked Questions
Do I need co-owner consent to subdivide my apartment?
It depends. For a physical (internal) subdivision without changing millesimal shares, the condominium regulation just needs to not explicitly prohibit it. For a legal subdivision (separate KAEK codes, ability to sell), 100 % consent from all co-owners is required, unless the regulation explicitly grants the right to unilateral amendment.
How much does it cost to subdivide a 100 m² apartment?
The average cost ranges between €35,000 and €50,000. This includes construction works (~45 %), M&E installations (~30 %), engineer fees & studies (~15 %), and legal/notarial costs (~10 %). The exact cost depends on the scope of work and the location.
What permit is needed from the planning authority?
If the changes are strictly internal (non-load-bearing walls, plasterboard), a Small-Scale Works Approval (EEMK) may suffice. If a new entrance, façade changes, or structural reinforcement are needed, a full Building Permit via e-Adeies is required.
What is the difference between physical and legal subdivision?
Physical subdivision involves internal construction changes (demolishing/building walls, new bathroom/kitchen) so that two independent apartments function - ideal for renting. Legal subdivision additionally includes amending the horizontal property deed at the notary, with separate millesimal shares and KAEK codes - necessary if you want to sell one of the two units.
Can I subdivide if the condominium regulation is silent?
Based on case law, if the regulation says nothing, physical subdivision is permitted provided that load-bearing elements and common areas are not affected. However, for legal subdivision (transfer/sale), 100 % co-owner consent is still required.
Is a parking space required for the new apartment?
In many municipalities, subdivision creates a new independent property that triggers mandatory parking-space requirements. If no space is available, a parking-space buy-out from the municipality may be required (costing several thousand euros).
Need help with your subdivision?
Our team handles the study, permits, and construction. Contact us for a free initial assessment.
Contact UsThe data provided are estimates and general guidelines based on current legislation (2026). Each property is a unique case and requires an individualised study by a lawyer and an engineer.