Basement: From Storage Room to Living Space – Everything You Need to Know

Converting a basement into a main living space (apartment, playroom, guest room) is one of the most common urban planning interventions. However, the line between legal use and arbitrariness is thin.

🔍 What is defined as "basement" today? According to the New Building Regulations (NOK), a space is considered a basement when its ceiling does not exceed 1.20 m from the final ground level. Please note: Before 2012 (under GCR '85), this limit was 1.50 m, which often causes confusion in older properties.

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💡 Basement vs. Semi-basement

Although the term "semi-basement" does not strictly exist in law, in practice it is used for spaces that:

• They have a ceiling higher than 1.20 m from the ground.

• They have standard openings (windows/doors).

• Important: If one side is completely "uncovered" (e.g., on sloping ground), the space can be counted as ground floor.

🛠️ Requirements for Legalization or Conversion

In order for an auxiliary space (storage room) to become a legal residence, the engineer examines:

1. Building Balance: The conversion to residential use is counted in the Building Coefficient (BC).

2. Building Specifications: Minimum clear height (usually 2.50m), adequate natural lighting and ventilation.

3. Use in the License: If the license states "Basement - Storage," using it as a home without changing the license is illegal.

⚖️ Settlement of Arbitrary Actions

If you have already converted your basement into living space, you can "regularize" it (Law 4495/2017) provided that the change was made before July 27, 2011.

• Evidence: Public documents (E9, leases, contracts) or, in some cases, the date of electricity connection to the property are required.

💡 Tip: Each case is unique, especially in traditional settlements or unplanned areas where special provisions apply. An inspection by an engineer is the first and essential step.