Change of Use: From Residential to Commercial – Procedures and Legal Requirements
- Ana Carolina Santos
- Nov 17
- 4 min read
The transformation of a residential space into a commercial establishment is increasingly common in Portugal, whether driven by property owners seeking to make their assets profitable or by entrepreneurs looking for strategic locations for their businesses. However, this change of use is not a simple or automatic process — it requires compliance with specific administrative procedures and strict legal and technical requirements.
This article explains in detail the legal framework, procedures to follow with the Municipal Council, technical constraints to consider, and practical aspects to know before carrying out the change of use from residential to commercial in Portugal.
What is a Change of Use?
Under the Legal Framework for Urbanisation and Building (RJUE), a change of use is an urban operation that involves altering the intended function of a building or autonomous unit. Changing from residential to commercial use is a significant transformation because it shifts from private, residential use to an activity typically open to the public and involving business or service operations.
This process always requires prior control by the Municipal Council, regardless of whether or not construction works are involved.
Applicable Regime: Prior Communication or Licensing?
The change of use from housing to commercial premises can follow two possible procedures, depending on whether construction works are required:
Prior Communication with Deadline (if no additional works are required):
Municipal review period: 20 days.
The applicant submits the communication with all required documentation.
The municipality may reject the communication if non‑compliances are found.
Licensing (if construction, alteration, or extension works are needed):
A more complex procedure requiring architectural and engineering projects.
Assessment periods between 120 and 200 working days depending on scope.
Administrative Procedures
1. Preliminary Feasibility Check
Review the Municipal Master Plan (PDM) and any applicable territorial management instruments:
Confirm whether the zone allows commercial or mixed use.
Identify restrictions or limits for specific types of commerce.
Check for public easements or special protection zones.
Conducting this verification avoids investing in projects that are not feasible under urban regulations.
2. Hiring Qualified Professionals
The process generally requires the involvement of licensed architects and engineers. These professionals must:
Prepare any necessary alteration projects.
Provide statements of responsibility ensuring legal compliance.
Supervise the project and guarantee safety, health, and accessibility standards.
3. Filing the Application
Common required documents include:
Application identifying the owner and property.
Statement of responsibility from the technical designer.
Property location plan.
Property registry certificate.
Proof of municipal fee payment.
When works are involved, additional documents such as architectural and specialised engineering projects, accessibility plans, and descriptive reports are required.
4. External Consultations
Depending on the intended business type and site characteristics, consultation with other entities may be necessary:
Health Authority.
Civil Protection Services (fire safety).
Infrastructure utilities (water, electricity, gas).
ICNF (if in protected areas).
Regional Directorate of Culture (if classified heritage).
These consultations often extend the process timeline.
5. Decision and Title Issuance
After review, the Municipality issues:
Admission notice for prior communication cases, or
Use Change Licence for licensing procedures.
This title replaces the previous residential occupancy licence and legally qualifies the property for commercial use.
Technical Requirements
Accessibility: The Decree‑Law 163/2006 establishes standards ensuring accessibility for reduced‑mobility users, including minimum entrance widths (0.87 m), ramp gradients up to 6 %, and adapted sanitary facilities.
Hygiene and Comfort: The General Regulation on Urban Buildings (RGEU) requires:
Minimum ceiling height of 3 m for commercial spaces.
Adequate natural ventilation and lighting.
Independent, hygienic sanitary facilities with washable finishes.
Fire Safety: As per SCIE legislation, depending on risk category, establishments must include fire detection systems, extinguishers, emergency lighting, signage, and compliant evacuation routes.
Acoustic Insulation: The General Noise Regulation imposes strict soundproofing requirements and limits for noise emission, especially in mixed‑use or residential buildings.
Horizontal Property and Condominium Permissions
Amendment of the Constitutive Title:
A change from residential to commercial in a condominium building requires amendment of the horizontal property deed, recorded by public deed or authenticated document, and registered at the Land Registry.
Condominium Assembly Approval:
Unlike conversions from commerce to housing (which have simplified rules under Decree‑Law 10/2024), converting housing into commerce usually requires approval by the condominium assembly, often by qualified majority or unanimity. Grounds for refusal include:
Incompatibility with the residential character.
Noise or security concerns.
Depreciation of remaining units.
Increased costs for shared services.
If refused, the owner cannot proceed even with municipal approval. Any works affecting common areas also require separate authorisation.
Sector‑Specific Licensing
Certain business types need additional sectoral licences:
Restaurants and bars: approval from the municipality and health authority, registration on Balcão do Empreendedor.
Educational institutions: authorisation from DGEstE.
Food retail: registration with ASAE and compliance with HACCP. Failure to secure these approvals renders the establishment illegal.
Enforcement and Penalties
Operating a commercial unit without proper authorisation may result in fines ranging from €250 to €44 891.81, suspension orders, and even administrative eviction. The inspection duty expires after 10 years from licence issuance, but illegal use remains subject to legal action from third parties.
Fiscal and Registry Implications
Tax property update: Mandatory communication to the Portuguese Tax Authority to adjust property classification and value for IMI and IMT taxes.
Land Registry amendment: Registration of the new permitted use is essential for legal validity.
Duration and Costs
Prior Communication: about 20 days.
Licensing with works: 6 – 12 months depending on consultations. Costs include municipal fees, professional fees (architectural and engineering), works, notarial acts, and sector‑specific authorisations.
Practical Advice
Before starting:
Verify zoning and condominium rules.
Request prior information from the Municipality.
Hire qualified professionals.
During and after:
Keep communication open with authorities.
Obtain all required titles before starting activity.
Register the change and update tax details.
Key Takeaways
Changing a property from residential to commercial use is more than an administrative process — it reshapes the building, the street, and its urban context. Legal compliance, proper planning, and professional support are crucial to ensure project viability, safety, and social acceptance. Properly managed, such a conversion becomes a sustainable, legally secure investment contributing to urban revitalisation.
Need specialised support for your change‑of‑use project? AC‑Arquitetos can accompany you through every stage — from feasibility studies to final approvals — ensuring compliance and efficiency. Contact us for assistance that makes complex procedures clear and achievable.
