Thermoleisure Centre

Balaruc-les-Bains / Hérault,

Looking across the water

Balaruc-les-Bains is a village in the Hérault département, situated beside the Thau lagoon, opposite Sète. It is an historic spa, and the second most popular in France for the treatment of rheumatic and phlebitic conditions. Its Athéna and Hespérides units, which offer a range of specialist therapies, opened in 1969, and they have now been joined by the O’Balia centre, which was conceived and designed by Tectoniques.
The centre sits beside the lagoon, close to Hespérides. Its purpose is to enlarge the range of services offered by the spa so as to cater for younger age groups and those who are concerned with “wellbeing”. The new facilities embody “thermofun”, i.e. their function is not exclusively curative. Between the serious nature of hydrotherapy and the exuberance of recreational water-based activities, the architects came up with a concept that did not just replicate the ambiance of the traditional spa, the municipal swimming pool, the water park or the codes of “designer wellness”.
The complex fits soberly into a setting with a strong personality. Its graphic presence is based on the use of wood, with lines and textures that create ever-changing views, bathed by the southern sun.

In situ

The surroundings are typical of the Mediterranean coast, with its lakes and teeming wildlife. But the climate can be challenging. The winds are frequent and strong; the light is hard, with sharp contrasts; the level of humidity is high, and the summer heat intense. These conditions must be taken into account, if not ameliorated, by any architectural project. Protection from the elements must also be provided, along with an enjoyable experience for the visitor.

The architects and landscape designers proposed an overall approach that incorporated a certain idea of leisure and wellbeing, ethics and eco-responsibility. Their objective was that the complex should be calm and tranquil, and that it should to some extent blend into the background. On the landward side, a wooden structure similar to others in the area emerges from the pines. And on the lagoon side, the dissimulation is more striking still. The waterline vegetation has been augmented to mask the building. As a result, the line of cypress trees and giant reeds is broken only by a belvedere overlooking the water.
The north and east faces of the building help protect the beaches and basins from the dominant winds. The western facade is sheltered by an embankment with vegetation that functions as a windbreak, reproducing a geographical feature that is naturally present along the side of the lagoon. It helps conserve and consolidate the indigenous plant life.

At the heart of the complex, sheltered from winds and indiscreet eyes, is an exotic garden that contrasts with the overall landscaping of the site. The architects’ aim was that this exogenous entity, curling round the different basins, should lend a certain “otherness” to the project. Palms, banana trees, papaya, yucca, crane flowers and sugar cane have been added to the well-known Mediterranean vegetation (oleander, umbrella pines, Aleppo pines).
Another essential objective was to control solar protection and the light-shadow balance using screens, pergolas and plants for beaches and open spaces.
The response to the problems of humidity and salinity was to use untreated wood of large cross-section, highly ventilated. And it should be pointed out that besides the “seaside effect”, the water that circulates through the complex is highly corrosive, as are the accompanying mists and sprays. Metal, including stainless steel, is particularly vulnerable in this type of situation. Wood is longer-lasting.

A composition of lines and circles

The design of the project was based on two simple geometrical forms: lines and circles. The lines are represented by constructed elements. The circles are associated with water, and its containment.
The lines structure the project, absorbing differences in level. Their function is to harmonise movement and preserve the aquatic spaces. They are mainly to be found along the broadest slope, which is perpendicular to the lagoon, as a transition between the shoreline and the urban character of the main entrance and the car park. And this linearity is further accentuated by the long belvedere that stretches out above the lagoon, with a magnificent view over the water and the oyster park. The horizontality of the buildings softens the architectural forms, thereby avoiding any hint of confrontation, or jarring visual effects. The orthogonal configuration is simple and compact.
The circular, sinuous watercourses give an organic feeling that is similar to nature’s own compositions. The different circles and lines structure the site, but without confronting or dominating it. A range of “environmental” building materials confirms this harmonious impression.

(Sana) per aquam

Water is at the heart of the project, in many different forms: rivulets, basins, jets, fountains, overflows, cascades, rain, runoff, foam, vapour. Activities based on water have developed considerably over the last few years, moving progressively from the realm of sport to that of play. And spas have not ignored this tendency. The therapeutic virtues of water, and the associated treatment programmes, can no longer be confined or restricted to clinical practice. Pleasure and wellbeing are gaining ground over purely medical considerations.
The O’Balia centre offers a wide range of activities: hydromassaging and hydropooling, upstream swimming, high-pressure jets and fountains, blast nozzles, microbubbles, beaches and massaging benches, children’s bathing and games, polar showers, caldariums, thematic and play showers, ice fountains, and of course the Onsen, or Japanese hot bath, which is one of the centre’s most popular attractions. Foot baths and showers are also used in some of the “water games”.

The complex takes the form of a tree-lined itinerary along which the different activities are located. It is based on a “rain road” formed by an insulated, heated gallery that has been cut into the terrain on the southern side. The equipment can be used all year round, the basins and activities being accessible from the exterior. There are distinctive showers (icy water, spa water, fresh water), a caldarium and a sauna.
The outer aquatic part consists of three successive basins that flow into one another. Each has its own scenario, and a different temperature, the coolest being on the eastern side and the hottest in the Onsen. During cold weather, the mists rising up from the water form a layer that looks surprising in a Mediterranean context.
As a complement to this aquatic itinerary, the rectilinear part of the programme has somewhat more classic “wellness” spaces: massage and treatment cabins, a hammam and a sauna. And there is a multipurpose area for light gymnastics. There are also relaxation spaces and a large pergola on the southern side of the building.

In order to reinforce the aquatic scenography, Lucas Goy, the lighting designer, came up with a novel plan in which water is treated as a “matter of light” and a source of lighting. LEDs are incorporated into spouts, borders and cascades; they embellish jets, vapour and spume. The springs are invisible. It is water itself that conveys and distributes light. The building, on the other hand, is illuminated in a sober, discreet way, bringing out the textures of the wood and the lines of the structure.
This lighting project was awarded the Prix du Patrimoine Bâti (for the French architectural heritage) by the Association Française des Concepteurs Lumière.

The O’Balia centre is part of a new wave of projects undertaken by Tectoniques, involving leisure activities, holiday accommodation and wellbeing. The simplicity of the forms, a peaceful, respectful relationship with the environment, a permanent concern for ease of utilisation, a committed environmental approach and, of course, the scent of wood – these are the centre’s fundamental features.

Discovery paths

The designers wanted the different ambiances to be varied and juxtaposed. The project embodies a random approach to discovery, with pathways and displacements that do not reveal themselves instantaneously: the visitor’s curiosity and desire are stimulated. Belvedere, shore, “rain road”, footbridges, terraces, gardens and beaches – each has its idiosyncrasies. The relatively small dimensions contain a geographic and topological heterogeneity that is emphasised by the lighting scheme.

Graphic motifs

The strong graphic identity of the complex results from the ways in which wood has been used to produce the lines and textures of the skin that covers the five faces of the building. This strategy is frequently used by Tectoniques to explore the facade “motif”, which is not simply decorative but also responds to constructive obligations. In visual terms, this texture has an architectural character that changes over the course of the day. With regard to the climatic ambiances, there is welcoming shade and graduated protection for the most exposed surfaces (the windows and roofs, the south and west facades).


Like all the agency’s projects, the O’Balia centre prioritises “dry construction”, with a marked preference for wood – a constructive mode whose advantages are well known. And in this particular case, which involved a delicate balance, and went through numerous changes, it opened up possibilities for versatility.
But there is another contextual argument for the use of wood, namely its high degree of durability, and particularly in aggressive situations like this, with the salinity and humidity of the coastal conditions and the hardness of the spa water. The wood that was favoured was untreated Douglas pine, which was used for the floors, weatherboarding, structures and screens. Concrete was of course used for the infrastructure, the technical premises (which are very important in this instance) and the basins.

Solar protection is systematic for the exposed glazing and the roof, which is equipped with a screen that sits above the main roof structure. The insulation is efficient, and foamglas was used in the parts of the complex that are exposed to a high degree of humidity.

In terms of energy consumption, the building is practically autonomous, given that the energy it uses is “free” and easily available. The basins are supplied with hot underground water via two deep boreholes. In fact the natural temperature of the water is higher than that required by the basins, so that they do not have to be artificially heated. And likewise, the buildings use heat recovered from a buffer pool.
For heating in winter, and the heating of the basins, the situation is close to that of Iceland. For summer heating, the idea was to avoid air conditioning and make use of the building’s passive properties, along with solar protection equipment. And the architects brought their client round to this viewpoint, except for the massage cabins, where an even temperature of between 22 and 24 °C has to be maintained. The double-flow air conditioning system in the cabin area has thus been equipped with a heat exchanger. For the other parts of the complex, the double-flow system operates in the usual way.

O’balia / Spa programme including pools, onsen, caldarium, hamams, saunas, massage rooms and fittness area

Client : Ville de Balaruc

Area :1200 m2
Budget : 6,2 M.€HT

Architects and engineers
Itinéraire Bis (paysagiste)
Les éclaireurs (conception lumière)
Brières (eau, electricité, gaz)
Anglade (bois)

Main firms
Shell: JMS Constructions
Wood frame, facades: Sud Est Charpente
Exterior carpentry, cladding: SAS J’allumine
Floor coverings: Carrillo
Water treatment, thermal pool: Crystal
Electricity, low-voltage current: SPIE
Main products and systems
Wood structures: Douglas pine
Facade structures, weatherboarding: Douglas pine
Struts and partitions: OSB
Aluminium frames: Wicona
Floorboards: Douglas pine
Linings and partition surfaces in Wab: Lafarge
Wood ceilings: Douglas pine
Metal ceilings: Luxalon
Double-flow ventilation:
Heat pump for thermal water:
Basin equipment: Fluvo
Lighting: Flux, Sammode, Detlight, Sill, Bega
SPA equipment: Emotec, Rehau, Duftdos
Siphons and runnels: Limatec
Tiling: Buchtal
Changing rooms: France Equipments