Change of use from commercial to residential: process, costs and returns

Changing the use of commercial premises to residential is one of the property investment strategies with the greatest margin potential in Spain. And also one of the hardest to carry out correctly. Not because it's impossible, but because it combines municipal planning law (different in every city), the technical rules of the Código Técnico de Edificación (Spain's Technical Building Code), specific tax rules and building-work management that leaves no room for improvisation.

Investors who do it well generate margins of 30% to 60% on the total cost of the deal. Those who do it badly end up with renovated premises that can't obtain a cédula de habitabilidad (certificate of habitability), planning enforcement proceedings and an asset worth less than when they bought it. The difference between the two lies in the prior due diligence, not in the execution.

Why commercial premises are an opportunity in 2026

Retail in Spain has been restructuring for years. The growth of e-commerce, changes in consumer habits and the concentration of retail in large shopping centres have left premises empty on the side streets of many cities. That stock, which has built up especially since the 2020 pandemic, has pushed commercial premises prices down.

The result: in many neighbourhoods of medium-sized and large cities, ground-floor premises now sell at prices per square metre significantly lower than equivalent flats in the same building. An 80 m² unit in a residential neighbourhood can be bought for €80,000-100,000 when an 80 m² flat in the same building is worth €150,000-180,000. If that unit can be turned into a home with a renovation budget of €50,000-70,000, the potential margin on the deal is obvious.

The first step: planning feasibility. Without it, nothing else matters

Before calculating any margin, before making any offer and before hiring any architect, you have to check whether residential use is allowed in those specific premises. And that depends on the municipality's urban development plan, not on any national regulation.

Every town hall classifies the ground floors on each of its streets. In some streets, commercial use of the ground floor is protected (mandatory) to preserve the neighbourhood's economic activity. In those streets, changing the use to residential is completely prohibited, even if the unit has been empty for years. In others, the ground floor has a permitted mixed use and the change is viable subject to a licence. In others still, residential use of the ground floor is allowed outright.

How to check it: make an in-person or online enquiry to the town hall's planning department, requesting a planning report on the plot and the floor of the premises. Most medium-sized and large town halls process it in 2-4 weeks. Some cities, such as Madrid, have it digitised and reply within days. Without that report, any decision to buy is built on assumptions.

The technical requirements of the Código Técnico de Edificación

Once planning feasibility is confirmed, the challenge moves to the technical side. The Código Técnico de Edificación (CTE) sets the minimum requirements that any home must meet, and commercial premises rarely meet most of them. These are the points that most often cause problems:

• Minimum clear height: Most regions require a clear height of at least 2.5 metres in rooms and 2.2 metres in passageways and bathrooms. Many ground-floor premises have ceilings of between 2.6 and 2.8 metres, which seems enough until you install a false ceiling to run the electrics, plumbing and ventilation. With a 20 cm false ceiling, an initial height of 2.7 m is left at 2.5 m. Tight, but viable.
• Natural light and ventilation: Every habitable area must have natural ventilation and light. Units with a street frontage (opening onto the street) usually comply. Interior units, or those with just one small window, are problematic and may require costly technical solutions (light wells, courtyards, etc.) that are not always architecturally feasible.
• Removing architectural barriers: Universal accessibility. If the building has no lift, or the entrance has steps with no ramp alternative, it can cause problems with the technical report. This point depends a great deal on the region and the municipality.
• Acoustic and thermal insulation: Commercial premises aren't built to the insulation standards of homes. The change-of-use project has to include solutions that comply with the CTE's DB-HR (the basic document on protection against noise) and DB-HE (the basic document on energy saving). This adds cost but is non-negotiable for obtaining the cédula de habitabilidad.

The administrative process step by step

Once planning and technical feasibility have been verified, the process for legally changing the use has these compulsory steps:

1. Technical project with the professional stamp (visado): An architect or aparejador (a building engineer) draws up the change-of-use project, which describes the work needed for the premises to meet the requirements for a home under the CTE and the municipal rules. This project must be stamped (visado) by the relevant professional association.
2. Application for the building works and change-of-use licence: It is submitted to the town hall together with the stamped project, the ownership documents and payment of the municipal fees. The time taken to decide varies enormously: some cities resolve it in 2-3 months, others take 6-12 months or more.
3. Carrying out the works: Once the licence has been granted, the works are carried out following the approved project. Any significant change to the approved project requires an amended project, which lengthens the timescales.
4. Certificate of completion: The technical director of the works issues the certificate confirming that the works have been carried out in accordance with the approved project.
5. Cédula de habitabilidad or licencia de primera ocupación (first occupation licence): Depending on the region, you apply for one document or the other. Without it, the property can't legally be lived in or let as a home.
6. Updating the Catastro (Spain's property cadastre) and the Land Registry: The description of the property has to be updated in both institutions so that it is recorded as a home. If you don't do it, the property is still recorded as commercial premises even though it has a cédula de habitabilidad, which causes complications with tax and with future sales.

What a change of use really costs in 2026

Costs vary a great deal depending on the size of the premises, their initial condition and the specific technical requirements. But there are reasonably reliable guide ranges based on real deals in medium-sized and large Spanish cities:

• Technical project and site management: Between €3,000 and €8,000 for 60-90 m² premises, depending on the firm and the complexity.
• Municipal fees: These vary by municipality. In large cities they are usually 3-4% of the works budget. For a €40,000 renovation, between €1,200 and €1,600 in fees.
• Cost of the works: The most variable item. For premises in basic condition that need a new layout, completely new installations and finishes, the cost of the works ranges between €600 and €1,000/m² depending on the specification and the city. A 70 m² unit can cost between €42,000 and €70,000 in works alone.
• Deeds of alteration and registration: Notary and Land Registry fees to update the cadastral description, between €1,500 and €3,000 depending on the value of the property.

Average total cost for 70 m² premises in a medium-sized Spanish city: between €50,000 and €85,000. On top of that comes the purchase price of the premises and the taxes on the purchase.

The tax side of a change of use

Buying resale commercial premises is taxed at the regional ITP (Impuesto de Transmisiones Patrimoniales, the property transfer tax) rate applicable in the region concerned. It is usually between 6% and 10% of the purchase price, although some premises sold by companies or developers are taxed with IVA (Spanish VAT, 21%) instead of ITP.

Once converted into a home, if it is let as the tenant's main residence, the investor can apply the 50% reduction on net income in the IRPF (Spanish personal income tax), which rises to 60%, 70% or 90% if certain requirements are met—provided the rental is long-term and not for tourists. That significantly changes the net return on the deal for private individuals.

If the aim is to sell the property once converted, the difference between the purchase price of the premises and the sale price of the home is taxed as a capital gain under the IRPF (or under corporation tax if the investor operates through an SL, a Spanish limited company). From that gain you subtract all the acquisition and conversion costs, which reduce the taxable base.

The cities where this works best

Not all cities are the same for this strategy. The factors that determine whether a change of use makes economic sense are: the difference in price per square metre between commercial premises and homes in the same area, the demand for residential rentals in the neighbourhood and how quickly the town hall grants licences.

Cities where the price gap between premises and homes is especially high and residential demand is solid: Valencia (neighbourhoods in transition such as Orriols or La Torre), Seville (Triana or San Pablo), Zaragoza (Delicias or Las Fuentes), Bilbao (Recaldeberri), and many cities of between 100,000 and 300,000 inhabitants where the stock of empty premises is high but demand for residential rentals is growing.

Madrid and Barcelona have more than enough demand, but the price per square metre in both cities has already absorbed most of the strategy's potential in almost every neighbourhood. The gap between premises and homes is smaller, the town halls are slower to process applications and competition from investors doing the same thing is higher.

The mistakes that kill the deal

There are three common ways for this strategy to fail:

The first is buying the premises before checking planning feasibility. It seems obvious that it has to be done first, but many investors fall in love with the price and make the offer first and the planning enquiry afterwards. If the planning scheme prohibits residential use on that frontage, you've bought premises that can only ever be premises.

The second is underestimating the cost of the works. Builders' initial quotes tend to be optimistic, and commercial premises hide problems that only show up once you start knocking down partition walls: rising damp from the floor, obsolete electrical wiring buried in the walls that has to be ripped out completely, a structure with less headroom than your quick measurement suggested. Always set aside at least 15-20% on top of the works budget as a cushion.

The third is getting the timescales wrong. A well-executed change-of-use process can take between 8 and 18 months from purchase to the first let. All that time you have capital tied up with no return. If your financial model needs you to start letting within 6 months, this strategy doesn't fit that plan.

Related resources: If you're looking for properties with high conversion potential, the inventory of cheap flats in Spain includes assets in different states of repair at below-market prices. To better understand the tax side of this kind of deal, the article on taxes on property investment covers the main taxes that affect investors. If you prefer ready-to-go assets with no works needed, bank repossessions are a direct alternative with real discounts.