What pays off more: renovating an old villa or demolishing and building new?
Three checks decide it, not the price per square metre: the condition of the structure, what current planning permits, and what survives of the old parameters after demolition. If the frame and foundations are sound, renovation is usually simpler on permits. If the structure has run out of life, a new house pays off.
On the coast there is a fourth check: whether the plot falls within a Ley de Costas zone. The rules for renovation and demolition there can differ, and a mistake is the costliest of all. So the decision is taken in this order: first a planning report on the plot, then a survey of the structure, then an estimate of both options on equal terms.
How do you assess the condition of the structure before deciding?
It is assessed by an on-site survey: an engineer or architect examines the frame, foundations, floors, roof and damp, and where needed takes concrete samples and exposes the reinforcement. Without that, any decision is a guess.
What is looked at most. Cracks: fine ones in the render are often cosmetic, while diagonal open ones in load-bearing walls are already a symptom. Concrete and rebar: near the sea corrosion of the reinforcement is faster because of salt in the air, and spalling cover says a lot. Floors: deflection and traces of moisture. Roof: many 1970s and 80s villas have exhausted waterproofing. Ground: soil and settlement, and in areas with a high water table a geotechnical report too.
A practical rule: when the cost of strengthening the structure approaches the cost of a new frame, demolition wins. Up to that point renovation usually saves both money and time.
Do the old building parameters survive demolition?
As a rule they do not: after demolition the new house is governed by the plan in force, not the one under which the old one was built. This is the main risk of the "demolish and rebuild" option, and it is checked before anything is signed.
The current plan sets the footprint, plot ratio, height, number of floors and setbacks from boundaries. It can happen that the old house is larger than today's plan allows. Then renovation may keep the existing volume, while demolition loses it and the new house comes out smaller. The regime for buildings that do not conform to the plan has changed in recent years, so you need an up-to-date report, not a neighbour's or the previous owner's account.
What to request. A planning report on the plot from the ayuntamiento. An architect's opinion on what may be built and what may be kept. For plots by the sea, Ley de Costas is checked as well, which is the subject of a separate article. Licence timelines and fees depend on the municipality and are confirmed with the ayuntamiento or a gestor.
How long do demolition and new construction take compared with renovation?
New construction usually takes longer than renovation at the design and permit stage, and on site the timing depends on complexity. Specific durations are calculated after the visit and the licence; they cannot be given in advance.
The sequence for a new house: survey and plot report, design (basic, then execution), demolition and building licence, demolition and removal of material, foundations and frame, envelope, services, finishes. Renovation has no demolition and no foundations, but it has structural strengthening and internal strip-out. Licences weigh heavily: timelines in Castelldefels, Sitges or Sant Cugat differ and are confirmed with the ayuntamiento.
Renovation is not always faster. An old house hides surprises: a floor with concealed cracks, undocumented alterations, damp behind a cladding. Each finding adds approvals and weeks. A new house is easier to plan because every decision is made on a clean plot; both options carry timing risk, just of a different kind.
Can you keep the foundations and frame of a 1970s villa?
Often yes. Many villas of that period have a reinforced-concrete frame with brick infill, and the frame is kept while everything else is redone: roof, envelope, partitions, services and finishes. This is called a deep renovation, stripped back to the frame.
Conditions. The concrete and rebar must pass inspection, the foundations must show no settlement, and any new loads (an extra floor, a heavy roof, a pool on the terrace) must be supported by calculation. If you increase the volume or change the number of floors, that is a separate permit and a separate check against the plan. Keeping the frame makes sense when the layout suits you or can be changed with partitions.
The benefit: less demolition and haulage, no groundworks, and sometimes a volume that you would not get in a new house is retained. The drawback: you are tied to the existing grid, and an ideal layout is harder than starting from zero.
How do you compare the two options in euros?
Compare the two options at the same finish level and with the full set of lines, otherwise the price difference is illusory. For renovation the estimate includes: survey, structural strengthening, envelope, services and interior finishes. For a new house: demolition and haulage, design and licence, foundations, frame, envelope, services, finishes and guarantees.
Three adjustments that are often forgotten. First, VAT: in our estimates it is usually 21% on renovating a resale home and 10% on building a new home; the applicable rate is confirmed by a gestor. The 21% applies because in our renovations materials usually exceed 40% of the taxable base; when they do not, renovating a private individual's home is taxed at 10% (Law 37/1992, art. 91). Second, the guarantee: Spain's Building Act (LOE) requires a ten-year guarantee against structural defects for new residential buildings, with an exception for a sole self-builder of a single-family home for personal use; legal liability periods are 10 years for structure, 3 years for habitability and 1 year for finishes. Third, the contingency: for renovation allow 10–15%, because there is more unknown.
And finally, the value of the plot and your plans for the house. If you want a pool, a basement or a different arrangement of rooms, a new build gives a freedom that renovation does not.
How does BCN YARD help you make this decision?
We run both lines, turnkey renovation and house building, so we can price the two options on one scale. After the visit you receive a renovation estimate and a new-build estimate with the same chapters, while the planning report on the plot is requested from the ayuntamiento by the architect and gestor. Project sign-offs are made by independent specialists.
We run projects in Russian and Spanish, one person is responsible for the project, and payment follows the contract in stages. We have full-cycle experience on a private house with a pool (2022–2024, solar panels). If you live abroad, you can discuss the plot by video and send photos and plans beforehand. We answer every enquiry within an hour.
Frequently asked questions
What pays off more: renovating an old villa or demolishing and rebuilding?
It depends on three checks: the condition of the frame and foundations, the building parameters under the current plan and the Ley de Costas regime if the plot is by the sea. A sound structure favours renovation; an exhausted structure, or a volume that would be lost on demolition, favours a new house. It is decided after a survey and two estimates on equal terms.
Do the old building parameters survive demolition?
As a rule they do not: a new house is built to the plan in force, and if the old one is larger than that allows, the volume can be lost. The regime for non-conforming buildings has changed, so request an up-to-date planning report on the plot from the ayuntamiento and an architect's opinion before any decision to demolish.
How long do demolition and new construction take compared with renovation?
A new house usually takes longer at design and permit stages, and build time depends on complexity. Renovation is not always faster: an old house hides surprises and each one adds approvals. Exact timelines are calculated after the visit and after the ayuntamiento confirms the licence timeline.
Can you keep the foundations and frame of a 1970s villa?
Often yes, provided the concrete, rebar and ground pass inspection and any new loads are supported by calculation. The frame and foundations are then kept, and the roof, envelope, partitions, services and finishes are redone. If the volume or number of floors must increase, a separate permit and a check against the plan are needed.