Underbuilds · Garages · Guest Suites · Damp Control · Project Management
Many homes on this coast have a garage or an underbuild that is used for little more than storage. Dragon Reforms turns that space into a guest suite, office, extra bedroom or utility room, and manages every trade so you deal with one team.
On a sloping Costa Blanca plot, the level beneath the main house is often the largest unused area a family owns. It may be a garage that no longer fits the car, a half-finished underbuild, or a room full of boxes. The footprint already exists, so the question is what it could become and what it takes to get there.
Turning a dark, cool, concrete-floored space into somewhere you would happily sleep or work is mostly about the things you cannot see in a photograph: moisture in the walls and floor, air and daylight, ceiling height, the route for pipes and cables, and how the room links up with the remaining rooms. Get those right and the finish is straightforward.
Dragon Reforms has been building and renovating homes across the north Costa Blanca since 1999. We open up walls, form new window and door openings, deal with damp, lay floors, run the plumbing and electrics, fit air-conditioning and finish the room, using our own teams under one person who keeps the sequence right.
There is one honest point to make at the outset. Whether a converted garage or underbuild can be used as living space depends on how the property is registered and what the town hall allows. We cannot promise permission. What we do is tell you what to ask at the survey, and a technical architect can confirm the position before you commit.
What is included
A conversion fails when one trade is left to solve problems that belong to another, so we plan the whole job first.
Underbuilds
The level under the house is usually the most promising and the most demanding space to convert.
Underbuilds are common where villas and townhouses are stepped into a slope. The lower level may be a bare shell of block and concrete, with a rough floor, no ceiling finish and a door or two onto the garden. It already has a roof, which is the house above, and that saves a great deal of cost.
What it lacks is everything that makes a room liveable. There is often no insulation, little daylight, limited ventilation and walls that are partly buried in the hillside. We start by reading the structure: which walls hold up the house, which face the earth, and where water goes in a storm.
From that, we propose a layout. A guest suite with its own bathroom, a bedroom for visiting family, a playroom or a home office are all realistic, and the design follows what the building will sensibly allow rather than what looks best on paper.
Garages
A garage is a ready-made room, but it was built to keep out cars and not to keep in warmth.
A garage usually has a concrete slab with no damp barrier, a large door in place of a window, thin or exposed walls and a ceiling that may be low. Each of these can be fixed. The large opening is typically infilled and replaced with a window or glazed door, and the slab is built up to give an insulated, dry floor.
Before any of that, think about where the car will go. Some owners have a second covered space or a carport, others accept parking outside. If the garage is also your only parking, converting it can affect how a buyer sees the property later, so it is worth weighing the decision.
If the garage sits within an apartment block or a community, the neighbours may have a say, because the door and facade are shared. We tell you what is likely to be needed and who to ask before you spend money on a design.
Damp
A below-ground or partly buried room will not stay dry by luck, so moisture control comes first.
Walls that face the hillside are exposed to water pushing in from the soil, particularly after heavy autumn rain. Concrete floors can draw moisture up, and condensation forms on cold surfaces in rooms with poor airflow. Treating only the visible stain without finding the source means it returns within a season or two.
We work out which kind of moisture you have. Depending on the findings, the answer may be drainage outside the wall, a waterproofing system on the inside face, a new damp-proof layer under the floor, or better ventilation. Often it is a combination, and our damp proofing and tanking team carries it out.
Only once the walls are dry and sealed do the plasterers, tilers and decorators begin. Finishing first and waterproofing later is the most common reason a conversion that looked fine at handover smells musty a year on.
Light and Air
The difference between a cellar and a bedroom is mostly light, airflow and headroom.
Daylight depends on where the walls are above ground. A garage door can become a wide window, and a wall facing a terrace or a lower garden may take a door. Where the room is buried, a lightwell or a high-level window can bring in more. Each opening cuts through structure and needs the right lintel and support.
Ventilation matters as much as glass. A bedroom or office needs a way to move stale air out and fresh air in, and a shower needs extraction. We plan this with the electrician and the air-conditioning installer, so the system does not rely on someone opening a door.
Ceiling height is the limit we cannot always change. If the slab to ceiling distance is low, lowering the floor is expensive and sometimes unwise for the structure. We measure first and tell you honestly if the room will feel too tight for its intended use.
Permissions
This is the part of a conversion that needs a straight answer before any money is spent.
In Spain, a property is registered with particular uses and areas. A garage or underbuild may be recorded as non-habitable, storage or parking, even if the space is physically suitable for living. Whether that can be changed, and whether a licence is needed for the works, depends on the town hall and the plot.
We are builders, not lawyers or architects, so we do not pretend to settle this for you. At the survey we tell you what to check, what documents to bring, and what questions to ask the town hall. A technical architect can confirm what is permitted, and we can work with the one you choose.
There is no guarantee of permission, and we say so plainly. Some owners convert for private use such as storage, a workshop or hobby room, which may be treated differently from sleeping space. What is right for you depends on your property, so ask before you build.
Before you hire
A cheap quote that skips the awkward questions often costs more by the time the room is finished.
A good contractor welcomes these questions because the honest answers protect both sides. If anyone is vague about damp, registration or who manages the trades, treat that as information about how the job will go.
Areas
We work from Callosa d'en Sarrià and cover the coast and the valleys inland.
Every area has its own housing mix, from apartment blocks with community garages to hillside villas with large underbuilds and old village houses with thick walls. Choose your town below to see how conversions work where you are.
Underbuild and garage conversions in Benidorm: block garages and ground-floor stores made into studios or offices, community rules explained. Free quotation.
View Benidorm →Altea underbuild and garage conversions: hillside villa lower floors and old town houses made into suites and studios, slopes managed. Free quotation.
View Altea →La Nucía underbuild and garage conversions: urbanisation villas gain guest suites, offices and family rooms below the house, damp handled. Free quotation.
View La Nucía →Finestrat underbuild and garage conversions: big villa lower levels under Puig Campana become suites and studios, with run-off managed. Free quotation.
View Finestrat →Underbuild and garage conversions in Calpe: apartment-block garages and villa lower levels fitted out against salt air and humidity. Free quotation.
View Calpe →Alfaz del Pi & Albir underbuild and garage conversions: long-established villas and apartments gain usable, easy-access lower-level rooms. Free quotation.
View Alfaz del Pi & Albir →Underbuild and garage conversions in Polop: thick-walled village house ground floors and hillside villa lower levels made usable. Free quotation.
View Polop →Underbuild and garage conversions in Benissa: finca outbuildings, stone lower floors and coastal villa garages made into guest rooms. Free quotation.
View Benissa →Villajoyosa underbuild and garage conversions: townhouse ground floors, seafront apartment stores and villa underbuilds made usable. Free quotation.
View Villajoyosa →Underbuild and garage conversions in Callosa d'en Sarrià, home of our office: village houses, valley fincas and terraced plots made usable. Free quotation.
View Callosa d'en Sarrià →Albir underbuild and garage conversions: holiday-home apartments and hillside villas gain guest suites below the Sierra Helada. Free quotation.
View Albir →Questions
Physically it is often possible, once the floor, walls, window and ventilation are dealt with. Whether it may legally be used as a bedroom depends on how the property is registered and what the town hall allows. We tell you what to ask, and an architect can confirm.
Often some form of permission or licence is involved, but it varies by town and property. We tell you at the survey whether the work is likely to need a licence from the town hall. We cannot guarantee permission will be granted.
First we find the source: water through the wall, rising through the floor, or condensation. Then we treat it with the right method, such as drainage, internal waterproofing, a floor barrier or ventilation, before any plastering, tiling or decoration begins.
Yes, where drainage can be routed properly. Lower levels sometimes sit below the sewer line or main drain, which may call for a pump. We check this at the survey and tell you what is realistic for your space.
A well-insulated, well-ventilated lower room is often cooler than the rooms above. We advise on insulation and fit air-conditioning sized for the space, so it stays comfortable and you are not running it flat out.
Yes. We speak English and Spanish, send photos and short videos as the work progresses, and can hold video calls at key decisions. One team manages every trade, so you are not chasing separate contractors from another country.
Contact us and we arrange a visit to measure the space and talk through your plans. The quotation is free, with no obligation, and it is put in writing before anything starts. Work is guaranteed, with the scope of the guarantee set out in it.
Related services
Get in touch
Tell us what you have: a garage, an underbuild or a room that has become a store. We will visit, look at the structure and moisture, and explain what is possible and what is not.
The quotation is free and carries no obligation. English and Spanish are spoken, and we are used to managing work for owners who are not on site.
Customer reviews
Genuine Google reviews from Dragon Reforms customers.
Professional Collaboration & Complete House Renovation – Calpe
“We have been collaborating for many years on projects both large and small, with excellent results. Our latest collaboration was the complete renovation of a house in Calpe. Thanks to their professionalism and reliability, they were able to handle all phases of the project. We hope to continue working together for many years to come.”
Complete Apartment Renovation – Benidorm
“I would like to say a huge thank you to Dragonreforms. Nico and his team did an excellent job renovating our 2 bedroom apartment in Benidorm. This included a beautiful new bathroom, kitchen, flooring, interior doors, plumbing and complete electrical works. Truly amazing workmanship. You have made our dreams come true.”
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Tell us about the job and the property and we will get back to you to arrange a visit.
