How a renovation differs in Montemar, Bellamar and Playa
Each part of Castelldefels calls for a different renovation. On the Montemar slopes the brief is terrain, wind and view. In Bellamar it is the balance between plot and neighbours. Near the beach it is sandy ground, salt, dense building and noise. The interior may look alike; foundations, facade and logistics are what differ.
The boundaries between neighbourhoods are loose, so look at the specific plot: slope, distance to the sea, street width and the year the house was built. Two neighbouring houses can need different approaches if one sits on a terrace and the other in a cut.
Before design we ask for three things: the cadastral extract and plot plan, the original house project from the municipal archive, and photos of every facade taken from street level. That is usually enough to show where to dig deeper.
What the ground is like near the coast and why it matters
Near the sea the ground is usually sand or silty sand with a high water table, and without a geotechnical report neither an extension nor a pool can be designed properly. On the slopes the ground is different: firmer, but sloping, so retaining walls and drainage matter.
In practice, a house near the beach may have settled if it was set on shallow foundations; a new storey or heavy stone cladding will use up whatever margin is left. A basement or pool below the water table needs generous waterproofing and sometimes dewatering during works. On a slope, the geotechnical engineer checks slope stability and the pressure on walls.
The owner orders the study before design starts, not the structural engineer halfway through. The cost of boreholes and a report is nothing next to the cost of a mistake: redoing the foundations of a finished house costs several times more. What such a study covers is explained in our guide on topography and geotechnics.
How closeness to the sea affects materials
On the front line, anything metal lasts half as long as it would inland unless it is protected. Choosing materials for a salty atmosphere is a design decision, not something to fix in the finishes schedule at the end.
For outdoor hardware, balustrades and fixings we use stainless steel AISI 316 rather than 304, because in marine air 304 pits and stains. Aluminium windows get powder coating to a marine grade, and the coating thickness is checked. Timber on the facade and terrace should be thermally modified or tropical, with regular oiling; ordinary larch greys within a couple of seasons. Natural stone outdoors needs to be low in porosity or sealed, otherwise salt comes through as a white film. Outdoor electrics are specified with a high ingress protection rating.
On the Montemar slope there is less salt but more sun and wind, so the fixing of awnings, glazing and light structures needs attention.
Can you add a floor, and what the plot decides
You can add a floor only within what the local plan allows for your plot: maximum height, number of storeys, built-up percentage and setbacks. The answer comes from the municipal planning department, not from what the owner wants.
The parameters in Castelldefels vary by zone. In the dense area near the beach, height and storeys are usually tighter and plots narrower. On the slopes there are bigger plots, but with limits on silhouette, volume and the maximum gradient around the house. The house may also have been built over the limit or with extensions that never had a licence, in which case legalisation comes first and the extension second.
The first step is asking the town hall for the planning parameters of the plot and checking them against the cadastre and the land registry. The second is a massing sketch with the architect. Only after that does it make sense to discuss the interior of the new floor. The general principles of extensions are covered in our guide to home extensions.
How machinery gets in and where materials are stored
A narrow street or a steep approach decides which crane, lorry and concrete pump you can use at all. You need to know this before signing the estimate, because hand-carrying materials changes the price.
On the Montemar slopes we check turning radius and approach gradient: a loaded lorry will not climb everywhere, and concrete has to be pumped over a long distance or moved by barrow. In the Playa area the streets are shorter, but parking is tight and unloading needs a permit to occupy the pavement or the road. In high season, delivery and noise restrictions are stricter, so agree the schedule well in advance.
Storage on the plot is planned from day one: where tile and stone are kept, where the spoil goes, how pallets are protected from salt and rain. The skip position and who takes it away are agreed separately.
Beach noise, wind and plot privacy
Beach noise and wind are solved with windows and layout, not wall thickness. A bedroom near the sea works better facing the courtyard, with the view-side living room closed off by well-insulated glazing.
For houses near the beach, the summer noise is people, music and bars late into the night. What helps is glass of different thicknesses in the unit, seals around the whole perimeter of the frames, and the bedroom on the side away from the street. On the slopes the wind is stronger: it hits large sliding systems, whistles at corners and moves light terrace furniture. Louvres, glass wind screens and planted screens reduce it without losing the view.
Privacy is a landscape matter: the height and type of boundary, a living hedge, a pergola over the pool. The pool is designed with the wind in mind so that loungers and water sit in a sheltered zone rather than in a draught.
Facade requirements and permits
A facade in Castelldefels goes through the town hall if you change its appearance, openings, colour or height. An interior renovation without structural work is usually simpler and follows a lighter procedure.
In practice the order is this. Minor interior works: a notification or a minor works licence. Changes to the facade, windows or roof: a major works licence with a project signed by an architect. A pool, retaining walls and a vertical extension are separate matters with their own paperwork. If the house is in a protected area or on a heritage list, requirements are tighter. Neighbours are checked too: distance to the boundary, shadows, views.
We run these projects in Russian and Spanish, with one person responsible for the job. First a site visit and measurements, then a staged estimate. Premium renovations start from 3,000 EUR/m2 excluding VAT at the Luxury level; the exact price comes after we have seen the house. For more on renovating in the town, see our guide to flats and houses in Castelldefels.
Frequently asked questions
How do Montemar houses differ from Playa houses?
Montemar means slopes, larger plots, views and wind, so retaining walls, terraces and awkward access. Playa means flat sandy ground, dense building, salt and noise. Foundations, facades and logistics differ as a result. The interior depends more on budget than on the neighbourhood.
Do I need a geotechnical report to renovate a house by the sea?
Not for interior work with no structural changes. For an extra storey, basement, pool or retaining wall, almost always: by the sea the ground is sandy and the water table high, and without a report the structural engineer cannot sign off the calculation. Order it before the first sketch so the design does not have to be redone.
What stainless steel suits terraces and balustrades near the sea?
On the front line use AISI 316 rather than 304, since it copes better with sea salt. Aluminium frames get marine-grade powder coating and timber should be thermally modified or tropical, oiled regularly. Small things like screws and hinges are usually where false economy shows up first.
Can I build a second floor in Castelldefels?
Yes, if the local plan allows it: height, number of storeys, built-up percentage and setbacks. It starts with asking the town hall for the plot's parameters and checking them against the cadastre. A house with unlicensed additions is regularised first and extended afterwards.