Common areas and private areas in co-ownership: legal framework, responsibilities, and best practices

In Belgium, co-ownership is governed by Book 3, Chapter IV “Property” of the Civil Code.

The distinction between common areas and private areas is not just a legal formality. It determines who can decide, who must pay, who is liable in case of damage, and which majorities are required at the General Assembly.

A thorough reading of the governing documents remains essential to avoid any misinterpretation.

Common areas

Definition and legal basis

Common areas are elements intended for the use or benefit of all or several co-owners.

They generally include:

• the land and surrounding areas

• the roof and façades

• load-bearing walls and structural elements

• staircases, elevators, and landings

• entrance halls and corridors

• shared technical installations (central heating, main pipes, shared networks)

The deed of co-ownership defines these elements, while the co-ownership regulations specify how they are used and how costs are allocated.

Some areas may be classified as “special common areas,” meaning they only concern certain units. In that case, only the relevant co-owners contribute to costs and decisions.

Management structure

The management of common areas relies on:

• the Association of Co-owners (ACP)

• the property manager (syndic), responsible for daily management and executing decisions

• the co-ownership council (if established), which supervises the property manager

• the auditor, responsible for financial oversight

Decisions are made at the General Assembly according to legal majorities:

• simple majority for ordinary decisions

• two-thirds majority for major works

• four-fifths majority for significant changes

• unanimity in exceptional cases

Proper preparation of technical and financial files is key to securing decisions.

Cost sharing and mandatory funds

Each co-owner contributes to common expenses in proportion to their share.

These expenses include:

• routine maintenance

• repairs

• maintenance contracts

Belgian law also requires the creation of a reserve fund to anticipate major works (roof, façade, compliance upgrades). This fund is separate from the working capital used for daily expenses.

Works on common areas

No modification to a common area can be carried out without prior approval from the General Assembly.

Even if a co-owner finances the work personally, collective approval is required if:

• the external appearance of the building is modified

• a structural element is affected

• the shared use is impacted

The required majority depends on the nature of the project.

Private areas

Definition

Private areas are elements that belong exclusively to a co-owner.

These generally include:

• the apartment or commercial unit

• cellars or parking spaces linked to a unit

• terraces or gardens, only if explicitly defined as private in the deed

However, some elements within a private unit (main pipes, technical shafts, structural components) may still be considered common.

Freedom and limitations

Co-owners are free to modify their unit, provided they:

• do not affect the building’s stability

• respect the building’s intended use

• comply with co-ownership regulations

• follow local planning rules

Purely internal works usually do not require approval unless they affect common or structural elements.

Restrictions

Some private works must be approved by the General Assembly if they:

• alter the façade or external appearance

• affect the structure

• change the use of the unit in a way that conflicts with the building’s purpose

Co-owners must also allow access to their unit for works of collective interest that have been properly approved.

Each co-owner must have insurance covering their civil liability, whether they occupy or rent out the property.

Practical examples

Installing air conditioning on a façade

Even if it serves a private unit, installation on the façade affects a common area. Prior approval from the General Assembly is required.

If it alters the building’s appearance or is visible from the street, planning permission may also be needed.

Replacing window frames

If window frames are classified as common elements, replacement must comply with collective decisions and aesthetic uniformity.

Damage caused by a leak

Identifying whether the source is a common or private pipe is essential to determine liability and insurance coverage.

Common issues in Belgium

Frequent challenges include:

• confusion between private and common technical elements

• outdated deeds after renovations

• insufficient reserve funds

• works carried out without prior approval

Effective management requires a proper legal analysis of governing documents and professional support for key decisions.

A structured and preventive approach

Belgian co-ownership is based on a balance between individual autonomy and collective governance.

Professional management aims to:

• ensure legal security of decisions

• anticipate financial obligations

• prevent disputes

• preserve property value

Clear rules and consistent application are the foundation of a stable and sustainable co-ownership.