Rehabilitation of Unauthorised Constructions: The Minimum Habitability Conditions under Ordinance 243/84
- Ana Carolina Santos
- 1 day ago
- 6 min read
Thousands of houses in Portugal were built over decades without any formal licensing process. The question many property owners face is: how can these buildings be legalised? An important answer lies in Ordinance 243/84, a legal instrument that establishes specific technical parameters for the rehabilitation of unauthorised buildings, allowing many of them to be regularised based on minimum habitability conditions adapted to the Portuguese context.
The historical context of Ordinance 243/84
Following the repeal of previous legislation, Decree-Law 804/76 created a regulatory void regarding the assessment of unauthorised constructions. Most of these buildings could never comply with the General Urban Buildings Regulation (RGEU) due to their pre-existing physical characteristics. Mass demolition would have led to devastating economic and social consequences.
Ordinance 243/84 (Portaria 243/84) emerged as a pragmatic solution, recognising that it is feasible and economically justified to legalise many unauthorised buildings based on specific technical tolerances. The aim was not to establish permanently lower standards, but to enable the technical conversion of existing constructions in a viable manner.
The Ordinance stipulates that most houses built without a licence can be legalised provided they meet minimum safety and habitability parameters appropriate to the real context.
Applicability of the Ordinance: The Scope of Legalisation
This regulation applies specifically to unauthorised residential buildings that can be rehabilitated. Before any formal technical inspection, the Municipal Council must assess whether the building and neighbouring constructions meet the essential safety and habitability conditions.
The starting point is crucial: only buildings with independent access and the possibility of direct connection to public infrastructure networks (water, sewage, electricity) may be legalised. Without these basic connections, legalisation is not feasible.
Dimensions and Areas of Rooms: Permitted Tolerances
One of the most practical aspects of Ordinance 243/84 concerns the minimum dimensions of internal rooms. The RGEU establishes strict parameters; the Ordinance introduces specific tolerances:
Minimum room dimensions
Rooms with reduced areas: Living spaces, excluding entrance halls, bathrooms, storage and similar, must have a minimum area of 8 m². This represents a significant reduction compared with standard regulations but provides genuine flexibility.
Dwellings with fewer than 5 rooms: At least one room must have an area of no less than 10.5 m².
Dwellings with 5 or more rooms: At least two rooms must have an area of 10.5 m² each.
Dwellings with more than 4 or 6 rooms: Up to 1 or 2 rooms, respectively, may have a reduced area of 7 m².
Kitchens: The minimum area is 5 m², which may be reduced to 4 m² if the dwelling has fewer than 4 principal rooms (excluding halls and sanitary facilities).
Proportions and Shapes of Rooms
To avoid excessively narrow or disproportionate spaces, the law establishes that the length of any room must not exceed twice its width and it must be possible to inscribe a circle of at least 1.8 m in diameter within the room’s plan. In kitchens with an area below 5 m², this circle may have a minimum diameter of 1.6 m.
Ceiling Height (Pé-Direito)
The ceiling height (free height from floor to ceiling) is crucial for habitability. The RGEU requires 2.70 m, but the Ordinance allows a reduction to 2.35 m for legalised unauthorised buildings. Special cases include attics, converted roof spaces and mansards: these may be used as living areas only if at least half of the room area meets the minimum reduced height of 2.35 m. However, the height may never be less than 2.00 m at any point more than 30 cm from the wall.
Horizontal and Vertical Circulation
Internal corridors must have a width of no less than 0.9 m to ensure accessibility and safety. In staircases of buildings with more than two floors, the width of flights may be reduced to 1 m if they are not enclosed between walls. Landings must be at least as wide as the flights, and steps must have a minimum tread of 0.22 m and a maximum rise of 0.193 m.
Sanitary Installations: The Essential Minimum
The Ordinance is flexible regarding the number of bathrooms. A single full bathroom is acceptable even in homes with more than four rooms, contrasting with the stricter requirements of the RGEU. Corridors for sanitary and general circulation may not be narrower than 0.9 m, ensuring personal hygiene can be carried out in conditions of minimum comfort and dignity.
Demolition of Internal Walls: A Possible Requirement
An important point: the law authorises the demolition of internal partitions when necessary to legalise the building. This obligation lies with the owner, ensuring that any illegal subdivisions can be reversed through construction works.
Additional Safety Conditions
In addition to dimensional criteria, the Ordinance requires the guarantee of fundamental safety conditions:
Independent access to the building
Connection to public infrastructure (water, sewage, electricity)
Absence of serious structural risks
Compliance with basic fire safety requirements
If any of these conditions cannot be met, legalisation is unfeasible and other solutions, including demolition, must be considered.
Technical Inspection Procedure
Before issuing a legalisation permit, the Municipal Council orders a technical inspection. This includes assessing adjacent buildings to verify that the rehabilitation of one does not compromise the structural safety of others. The inspection commission must include at least three legally qualified professionals authorised to design building projects. This procedural rigour ensures that legalisation does not undermine public safety.
Practical Advice for Property Owners
✓ Consult the Municipal Council early
Before investing significantly in renovation works, request a preliminary assessment from the Municipal Council regarding the feasibility of legalising your property. Some buildings lack the basic conditions required, making legalisation impossible.
✓ Gather building documentation
Identify when and by whom the building was constructed, and locate any original land records. This information facilitates analysis.
✓ Hire a Qualified Professional
Legalisation requires a technical report drawn up by a qualified architect or engineer demonstrating compliance with Ordinance 243/84. This is an essential investment.
✓ Estimate potential works
If technical inspection identifies necessary adaptation works (widening doors, removing partitions, structural improvements), obtain cost estimates from specialised contractors to make informed decisions.
✓ Do not overlook structural defects
If the building shows cracks, serious dampness or instability, these issues must be resolved before legalisation. The Municipal Council may refuse to legalise any building that compromises public safety.
Limitations and Cases of Impossibility
Not all unauthorised buildings can be legalised. Ordinance 243/84 does not apply to buildings situated in protected areas, near watercourses at risk of flooding, or in zones lacking essential infrastructure where provision would be economically unfeasible. Likewise, buildings that significantly harm the landscape or lie within archaeological, historical or natural protection zones are unlikely to be legalised.
Contemporary Relevance of the Ordinance
More than 40 years after its enactment, Ordinance 243/84 remains the legal mechanism through which thousands of informal homes in Portugal secure regularisation. It represents a pragmatic balance between technical-legal rigour and socio-economic reality.
However, application of this Ordinance varies significantly between municipalities. Some adopt more permissive criteria; others interpret the requirements more strictly. This reinforces the importance of consulting the local authority for specific applicable criteria.
In Summary
Ordinance 243/84 provides the legal framework by which unauthorised residential buildings in Portugal can be rehabilitated and legalised, provided they meet minimum habitability conditions adapted to real pre-existing circumstances. Reduced room dimensions, lower ceiling heights, and flexible bathroom requirements are tolerances that make the conversion of many informal buildings feasible.
However, legalisation is neither automatic nor guaranteed. It requires a rigorous technical inspection, compliance with safety standards and access to essential infrastructure. Buildings suffering from serious structural defects, located in risk areas or lacking utility connections are rarely legalisable.
For owners of informal dwellings, the first step is to contact the competent Municipal Council to understand whether their property can be legalised and what investments would be required. The support of a qualified professional is essential to navigate this complex process.
Clarify the status of your home
Owners of unauthorised constructions often face uncertainty regarding their legalisation prospects. Issues such as insufficient dimensions, lack of infrastructure, or structural deficiencies may prevent legalisation.
AC-Arquitetos offers an initial assessment of the feasibility of legalising informal dwellings based on Ordinance 243/84 and complementary legislation. We prepare technical reports demonstrating compliance with minimum habitability conditions and coordinate the entire procedure with the Municipal Council. Contact us to understand whether your home can be legalised and what steps must be followed to regularise its legal status.
