Change of use problems in Barcelona: 10 common obstacles and how to solve them

By Sergio Sanz, architect · Published 9 July 2025 · Updated 27 October 2026

Most change of use problems in Barcelona have little to do with the refurbishment itself and a lot to do with everything around it: planning rules, the owners’ association, natural light or the route of a flue up to the roof. Premises can be spacious, bright and on a good street and still never be able to become a home.

In this article we go through the ten problems we come across most often in feasibility studies, why they make a project fail and what can be done in each case. For the full explanation of requirements, regulations and procedures, see our guide to converting commercial premises into a home in Barcelona.

1. Density: the building must allow one more home

This is the first check and the one that rules out most projects. Each plot has a maximum number of dwellings, obtained by dividing its built or permitted floor area by the planning density module (in Barcelona, where the zone does not set another one, 80 m² of floor area per dwelling under article 180 of the Metropolitan Building Ordinances).

If the building already has that number of homes —including any added with a licence after the original project—, no more can be created, however well the premises meet every other requirement. Checking it requires a search of the municipal archive and an accurate calculation. That is why density tops the list of change of use problems: we explain it in built area and buildable area.

2. Insufficient floor area, frontage or ceiling height

In Barcelona, every new home must have at least 40 m² of usable area and 3 m of frontage to the street or the inner block courtyard; light wells do not count. Narrow premises with a 2.50 m frontage cannot become a home, however deep they are.

Clear ceiling height also rules out premises: a change of use requires 2.40 m in the living room and bedrooms and 2.20 m in the kitchen, bathroom and corridors. Height can sometimes be gained by lowering the floor or removing a suspended ceiling, but floor insulation and services also take up space and must be allowed for from the start. These are change of use problems you can already spot on the first visit, tape measure in hand.

3. Natural light and ventilation in deep premises

Of all change of use problems, natural light is the one that rules out the most large premises. Decree 141/2012 and the OME require the living room, kitchen and bedrooms to have direct natural light and ventilation from outside, with windows of at least 1/8 of each room’s area. In very deep ground floors with a street frontage only, the rooms at the back cannot be bedrooms.

The solution is to open onto the inner block courtyard or onto a light well that is large enough (3 m in diameter for bedrooms and living rooms). But in many Eixample ground floors the courtyard is covered by single-storey extensions, and if the bedroom or living room opens onto the inner block, the planning rules require that part of the plot to be left open, with a minimum of 6 × 4.5 m.

4. Kitchen extraction up to the roof

Kitchen extraction must run through an independent duct up to the roof (DB HS 3 of the Building Code and art. 66 of the OME), and Barcelona’s urban landscape bylaw does not allow it to exit through the façade. It is one of the most underestimated change of use problems: you need to find a route through a courtyard or a services shaft that is buildable and that the owners’ association accepts.

If there is no way to take the duct to the roof, the home does not comply and the project cannot go ahead.

5. The owners’ association and the bylaws

In Catalonia, the bylaws of the owners’ association can set the use of the commercial units (art. 553-11 of the Civil Code of Catalonia). If they say the units are commercial, they must be amended, which requires a general meeting resolution with the majorities set by the Code.

Even if the bylaws say nothing, works affecting common elements —façade, courtyard, roof, ducts, structure— need authorisation. It is worth reading the bylaws and the land registry extract before buying and, if a duct has to be installed or the façade changed, raising it with the association early on: of all change of use problems, this is the one that depends most on other people.

6. Neighbourhood restrictions and listed buildings

Some amendments to the Metropolitan General Plan approved for specific neighbourhoods ban ground-floor homes on certain streets, such as the one for Clot-Camp de l’Arpa (2025), and other neighbourhoods have their own conditions. In listed buildings, the Heritage Catalogue record limits what can be altered, and in non-conforming buildings the permitted works are very restricted.

These problems do not depend on the design: if the rules do not allow it, there is no technical solution.

7. Insulation, damp and radon: the cost problem

This is the least visible of the change of use problems. The envelope of the new home must meet the Building Code’s DB HE even if it is not altered, so the floor, the façade and sometimes the ceiling over the commercial unit or car park below almost always need insulating, and the shop-front glazing has to be replaced. If the premises are in contact with the ground, they must be protected against damp (art. 69 of the OME) and radon gas (DB HS 6).

Technically there is almost always a solution, but these items can make the change of use no longer worthwhile. That is why the feasibility study should also estimate the cost of the works.

8. Street access and accessibility

The Catalan Accessibility Code (Decree 209/2023) requires the new home to have a practicable layout. In addition, if the premises have two or more entrance steps, a practicable access must be provided with a ramp or platform lift, or space reserved for one, which sometimes means setting the door back and losing usable area. It is another of the change of use problems that shapes the layout.

9. The licensing process: licence, requests and timescales

Change of use problems do not end when the project is submitted. In Barcelona, a change of use to residential always needs a planning licence with an architect’s project and a prior planning report. The legal deadline for a decision is two months (three with a fire prevention report), but each request for corrections suspends it, and the City Council often asks for clarification on density or habitability compliance.

A common belief needs qualifying: the licence alone does not «guarantee» the change of use. What makes it final is carrying out the works in line with the project, obtaining the final completion certificate, notifying first occupancy and obtaining the habitability certificate. Only then can the former premises be registered as a home.

10. How to avoid change of use problems before you buy

Almost all change of use problems can be detected before spending money on the project. Our recommendation:

1. Feasibility study before buying the premises or signing the deposit contract: archives, planning, density, site visit and proposed layout.
2. Read the bylaws and the land registry extract, to find out whether the owners’ association can stop it.
3. Check the kitchen extraction route during the site visit.
4. Estimate the cost of the works, to see whether the operation still makes sense.

The opposite can also happen: the property may already be legally a home even though the deed says otherwise, or a flat registered as a home may not be one. We explain it in not everything registered as a home is a home.

Frequently asked questions about change of use problems

Regulations cited: Barcelona City Council, basic information on change of use to residential · Metropolitan Building Ordinances (AMB) · Habitability Decree 141/2012 · Spanish Building Code · Catalan Accessibility Code · Civil Code of Catalonia, book five. Reviewed in October 2026.