What to Consider When Renovating an Old House in 2026
Renovating an old house is one of the most complex projects you can take on. Not because it’s impossible, but because behind that charming façade there are often decades of outdated services, structures that need checking and surprises that no property listing ever mentions. If you are considering buying an apartment to renovate in Barcelona, it’s worth keeping this in mind from the start.
If you are planning to renovate an older home in Barcelona in 2026, here is what you need to know before you begin.
What counts as an old house?
In practical terms, we mean homes built before the 1980s. In Barcelona, that covers much of the housing stock in the Eixample, Gràcia, Sant Gervasi and other neighbourhoods with multi-family buildings from the early and mid-20th century.
These are apartments with high ceilings, hydraulic tile floors, façades of great aesthetic value… and services that haven’t been touched in decades.
First things first: assess the structure
Before choosing finishes or a layout, you need to know what structure you are working with.
In an old house, the critical points are:
- Floor slabs: many buildings from before the 1970s have timber or one-way slabs that may be in poor condition.
- Load-bearing walls: the interior layout may depend on walls that cannot be removed without structural work. We explain it in can I knock down a load-bearing wall?
- Damp: from rising damp, leaks or condensation. Invisible until the finishes come off.
- Condition of the roof and façade: especially relevant for top-floor and ground-floor apartments.
A qualified professional should check all of this before the project is drawn up. Skipping this step is the number one cause of budget overruns, which is why it is so important to start from a good renovation budget. For an idea of the figures, we explain how much it costs to renovate an old house.
Services: the chapter with the most surprises
In older homes, services are what drives up the cost of a renovation the most, and what people least expect. In 2026, upgrading them is not optional: it is required to meet regulations and ensure safety.
Electrics: if the fuse board is old and the wiring is aluminium or has no earth connection, it must be completely replaced. This is non-negotiable. Read more about home electrical system maintenance.
Plumbing: lead or galvanised iron pipes have been obsolete for decades. A complete renovation is the time to replace them entirely.
Heating and air conditioning: many old homes have water radiators with no zoning or temperature control. Switching to an efficient system —aerothermal heat pump, underfloor heating, fan coils— is an investment that pays for itself. Discover the types of home climate systems that save on heating.
Ventilation: buildings constructed before the NBE-CT-79 regulation were not designed for today’s level of airtightness. When you improve insulation, you need to make sure the air is properly renewed.
Permits and paperwork in Barcelona in 2026
In Barcelona, a complete renovation that affects the structure, the façade or communal elements requires a major works licence, while smaller-scale works are processed through a works notification (assabentat). The City Council’s processing times have improved, but they still need to be planned well in advance. If in doubt, check when a building permit is required.
What you need to bear in mind:
- Certified technical project: required to apply for the licence. It must be prepared by an architect or building engineer.
- Building protection: if the building has protection level A, B or C in the city’s Heritage Catalogue, there are restrictions on what can be changed on the façade, staircase or communal elements. That’s how we worked when we rehabilitated a heritage-protected building.
- Energy performance certificate: required before the renovated home can be occupied.
- Waste management: the construction waste management plan is part of the works file.
Having a team that handles the paperwork avoids delays and documentation errors.
What to keep and what to replace
Renovating an old house doesn’t mean wiping everything out. In many cases, the original features are the home’s greatest asset and help to increase the value of an old house with a complete renovation.
Worth keeping:
- Original hydraulic tile or mosaic floors in good condition (here’s how to preserve hydraulic tile floors)
- Ceilings with plaster mouldings or cornices
- High-quality solid wood joinery
- Wrought-iron features on balconies or staircases
Replace without hesitation:
- All electrical wiring if it dates from before the 1990s
- Pipes made of obsolete materials
- Windows without thermal break
- Any element containing asbestos (common in buildings constructed before 1990)
Why 2026 is a good time to renovate
The EU’s Next Generation funds for rehabilitation and energy efficiency improvements are still active in 2026, although deadlines are running out. If your renovation includes improvements to insulation, windows, services or efficient climate systems, part of the investment may be eligible for a grant. Learn about the benefits and savings of a home energy renovation.
Find out before you start: there are specific calls for homes in multi-family buildings that can cover a significant percentage of the budget. And don’t forget to check whether your project qualifies for the reduced 10% VAT on home renovations.
Who to work with to renovate an old house in Barcelona
A renovation of this kind needs a team that combines technical judgement, the ability to deliver and clear communication with the client.
At OAK Constructora Barcelona we have completed more than 300 complete renovations, many of them in older homes in the Eixample, Gràcia and Sant Gervasi; you can see them in our renovation and rehabilitation projects. We work with our own in-house team, a single point of contact per project and fixed quotes with cost-overrun control.
If you have an old house and are thinking about renovating it, we can help you understand what it involves before you make any decisions.