Locating the Casa da Musica was key in the development of OMA’s thinking: we chose not to build the new concert hall in the ring of old buildings defining the Rotunda but to create a solitary building standing on a travertine-paved plateau in front of the Rotunda’s park, neighbouring a working class area. With this concept, issues of symbolism, visibility, and access were resolved in one gesture.

As well as the Grand Auditorium, conceived as a simple mass hollowed out end-to-end from the solid form of the building, the Casa da Musica also contains a smaller, more flexible performance space with no fixed seating, ten rehearsal rooms, recording studios, an educational area, a restaurant, terrace, bars, a VIP room, administration areas, and an underground car park for 600 vehicles.

Innovative use of materials and colour throughout was another imperative: as well as the unique curtain-like glass walls at either end of the Grand Auditorium, the walls are clad in plywood with enlarged wood patterns embossed in gold, giving a dramatic jolt in perspective; the VIP area has hand-painted tiles picturing a traditional pastoral scene, while the roof terrace is patterned with geometric black and white tiles; floors in public areas are sometimes paved in aluminium.

There is deliberately no large central foyer; instead a continuous public route connects the spaces around the Grand Auditorium by means of stairs, platforms and escalators: the building becomes an architectural adventure.

Sustainability Statement
Casa da Musica as a major public concert hall building can not be gauged on the same basis as an office/residential block. Special temperature and humidity control is required in every room where instruments are either used, repaired or stored. In this context it is important that other factors than purely energy consumption are addressed when considering sustainability in the context of such a building.

Flexibility and Maintenance
The building is designed to create maximum flexibility to adapt to future requirements. Foyers, Rehearsal Rooms and the Small Auditorium can in turn be used as social spaces, music rehearsal rooms, performance space, workshop space etc.

All spaces are easy to maintain. Sound, light and other equipment is easily accessible and maintained in case of new requirements exchanged or added.

Materials
For the main structure we choose to use local aggregates, grey granite, instead of white limestone, traditionally used in Portugal for white concrete. Most finishes used are traditional local products, such as tiles and wooden floors. Other products, such as the facades, are produced locally.

Energy Conservation
The engineering systems have been developed from a rigorous analysis of the climate, operating scenarios and comfort requirements. The Portuguese climate is relatively temperate with intermittent high summer temperatures, a large diurnal range and moderate wind speeds. Passive environmental control has been utilised in the building form and construction wherever possible to reduce energy consumption. The building has very high thermal mass to optimise the use of the diurnal temperatures and reduce cooling and heating loads. The integration of glass has been minimised, however when required high-performance and highly tinted glazing has been used.

Lighting is a major consumer of energy. A careful selection of fittings and appropriate lighting levels reduces the building’s energy consumption. Lighting control systems ensure lighting is turned off when not in use.

All active engineering systems are selected to operate at high efficiencies. Furthermore the ventilation systems are zoned to allow them to be turned off or minimised when performances are not taking place.

All plant and equipment has been designed for accessibility and maintainability. This ensures reduced lifecycle costs and good operating lifecycles.