Not every commercial unit can be converted into a home. Before buying or starting construction, it is necessary to check planning compatibility, habitability conditions, access, ventilation, daylight, safety and the property’s documentation.
The most important check happens before you buy
The fact that a property is registered as a commercial unit and has enough floor area does not mean residential use will be permitted. An early feasibility study can identify constraints that may make the conversion unviable or significantly more expensive before you sign a deposit agreement or complete the purchase.
What needs to be checked?
- Compatibility of residential use with planning rules and the property’s planning status.
- Available floor area, clear height and feasible layout.
- Natural daylight and ventilation to habitable rooms.
- Access, means of escape, fire safety and accessibility.
- Acoustic performance, energy efficiency, health requirements and building services.
- Façade, courtyards, openings and potential restrictions from the homeowners’ association or the building itself.
- Available administrative, land-registry and cadastral background information.
Typical process
1. Preliminary feasibility study
The planning framework, existing condition and essential technical requirements are reviewed. If the unit cannot meet a critical requirement, it is better to know before developing the full project.
2. Survey and layout proposal
The property is documented and a layout is developed that can meet residential requirements while coordinating structure, building services, ventilation, daylight and access.
3. Technical project and approvals
The technical documentation is prepared and the required authorization procedure is followed. In the municipality of Murcia, the current 2026 framework includes a specific responsible declaration procedure for works involving a change of use from commercial premises to residential use; certain cases involving essential changes to the external composition, volume, overall envelope or main structural elements may instead require an urban planning permit. The municipal procedure currently requires an architect-led technical project or technical documentation, and the Spanish Supreme Court judgment 700/2026 of 4 June 2026 confirmed the role of the architect where the intervention changes the building’s characteristic use. In other municipalities, the applicable procedure and documentation must be checked individually.
4. Construction administration and occupancy
During construction, the work is checked against the approved project and necessary changes are documented. In the municipality of Murcia, once the works are complete, the current technical framework provides for a responsible declaration of first occupancy, supported by the documentation demonstrating compliance with planning and technical requirements, without prejudice to subsequent municipal checks. When the intervention involves a complete reconfiguration and renewal of building systems, the work shares many control criteria with a complete renovation.
Changing a unit to residential use in Murcia: the 2026 regional rule
Article 21 of the Region of Murcia’s Decree-Law 3/2026 introduces a special regime for converting certain ground-floor units in buildings intended for multi-family housing. It is not blanket permission: planning, habitability and building requirements still apply, including flood-risk conditions. Units facing designated commercial corridors or situated in historic town-centre areas, as defined by municipal planning rules, are excluded from this particular regime.
The decree-law entered into force on 8 July 2026, but licence applications under this special regime may only be submitted once six months have elapsed. During that period, municipalities can opt out, restrict the eligible areas or introduce further conditions, including limiting the scheme to protected housing. Before purchasing a unit, the appropriate route must be checked: the existing municipal procedure may apply, or the special regime may become relevant. Neither route guarantees approval.
What documentation is useful?
- Location and cadastral reference.
- Land-registry extract, deed or contract, if available.
- Plan of the unit or an approximate survey.
- Photographs of the façade, access, interior, courtyards and openings.
- Information from the homeowners’ association when façade or common elements may be affected.
What can make the conversion unviable?
Common obstacles include planning incompatibility, insufficient façade or ventilation, inadequate clear height, inability to provide compliant means of escape, restrictions on creating new openings, impacts on common elements, or failure to meet minimum residential requirements. There is no single checklist that applies to every property: the specific unit and municipality must be reviewed.
Frequently asked questions
Can feasibility be checked without preparing the entire project?
Usually, yes. A feasibility study can be carried out first. Its purpose is to identify the main constraints and decide whether it makes sense to proceed with the complete technical project.
Is a change of use just an interior renovation?
No. In addition to the construction work, the planning use changes and the property must demonstrate the technical and administrative conditions required for residential occupation.
Should I sign a deposit agreement before the feasibility study?
The prudent approach is to assess feasibility before taking on an unconditional commitment. If the transaction is already being negotiated, legal advice should be obtained on how to reflect that condition in the agreement.
Are you considering a commercial unit?
Tell me where the unit is located and, if available, its cadastral reference. I can then explain which preliminary checks make sense. If plans or photographs are needed, I will tell you how to send them.