The project was the result of a limited design competition with a brief that placed a great interest in leading environmental design approaches. Thus the project team set up from the onset was a multidisciplinary group, both international and local which included Atelier Ten from London as environmental engineers. The completed building is already regarded as a showcase of leading edge environmental design, which has raised the bar not only for designers and clients alike in Ankara but the whole of Turkey. Indeed such a building would not find itself out of place even on the streets of London or New York.

The brief in many ways is typical of an HQ building, which houses essentially an association of contractors, who represent the crème de la crème of the construction industry in Turkey. These same contractors institute 33 of the largest main contractors of Turkey who are placed 2 nd only after China in the world. USA holds the third position. The building there fore is designed as a showcase of Turkish Contracting capabilities and is held as an example of what the industry is about. There fore the agenda to also establish itself as the most environmentally responsible institution in Turkey makes the Turkish Contractor’s Association a unique proposition in this market place. The functions include, apart from offices for administration and guidance, a series of public elements such as a conference hall, and exhibition areas as well as a resource library for visitors to the TCA.

The building articulates itself to reveal these functions, and is organised to reflect this as transparently as possible to the outside world. As you move up the building from ground up the increasing degrees of privacy required in the programme positions these elements in a natural hierarchy, placing at the top the most private lounge, and at the bottom the most public exhibition and conference spaces. The atrium cutting through the mass reveals on the other hand all of these
functions upon entry, while connecting the building to the street level to the public domain and rising to the top of the whole it also acts as a natural ventilation device for all of the open public spaces. TCA's basic principle of institutional transparency both conceptual and structural defines the design from the beginning.

An underground cooling labyrinth system is employed to exploit the diurnal temperature range of the local climate of Ankara, which in summer indicates a difference of 15-20 degrees between night and day. By using thermal mass this system optimises the building’s environmental performance to maintain occupant’s comfort in response to changing external temperatures while reducing energy
demand. At night-time, the cooler air from outside is passed through the labyrinth passageways to achieve rapid cooling across the whole labyrinth cell system. This effectively puts ‘coolth’ into storage for the following day as this naturally cooled air is distributed. In the winter-time, the heat from the soil is used to passively heat the daytime air. Galvanized steel pipes of 150mm diameter are laid within the mass of the concrete slabs to deliver air to chilled beams placed under exposed
concrete ceilings. The structural mass of the building surfaces is there fore utilised to take advantage of their thermal-mass absorbing the “coolth” from these pipes as the circulate through to the chilled beams. These units are placed in an optimal configuration within offices and spaces, and also double up as light sources both lighting up as well as down.

The external skin is made of two layers; the first a classic frameless glass to glass or glass to metal facade panel system. The second is a layer of stainless steel mesh shading. The delicacy of this screen system allows occupants to remain in touch with outside views while giving a responsive density to the mesh varying according to solar orientation and therefore exposure to sunlight. During day-time
the screen enables the functional masses to be articulated, while at night the internally lit building reveals the whole, becoming in an instant a kind of modern candle that glows gracefully at night. This transparency while inviting you in, allows one to retain a strong relationship with the outside world holding you within while reinforcing this relationship with the public domain.

Internally and externally an emphasis is placed on the use of natural materials, such as timber and stone, which contrast with the relatively hard surfaces of the exposed concrete surfaces. Lighting is the most critical aspect of the interiors as it is used to highlight these surfaces both directly and indirectly. Naturally all of the materials that are used are resourced locally, and chosen to minimize environmental impact.

Marble from the outside the city of Kastamonu is used on the North and North-West facades of the building as an external rain screen cladding system. The joints between the stone panels, which are hung from the concrete structure with a galvanized steel fixing system, are left open to allow rain to drain through the façade and out. This open detailing allows us to create a highly precise and crisp
detail between the stone panels. The stone is given a rough finish which exposes the fossil structures behind the surface layers and gives an organic feel to the façade treatment which contrasts with the refined and precise finishes of the glass, metal and stainless steel elements.

On all ground surfaces externally a darker basalt stone from Kayseri are used. Again the basalt is finished with a patina finish to give the stone a natural look. The selection of the dark stone makes the rest of the building hover above the ground as it gives the whole a natural base. The stone of the floor finishes are taken up the stairs and also in to the reflecting pool adjacent to the entrance.

Internally the materials are chosen to contrast with the use of steel structures, which are painted a dark anthracite metallic gray, while walls surfaces are finished in walnut veneered panels, glass and white acoustic paneling. The use of stone surfaces continues in to the ground level public areas, in the form of a polished stone from Afyon, in large panels to give the sense of having been carved out
of a large piece of stone. This element continues up the main stairs in the atrium.

Solar panels, solar cells, bicycle racks, recycling stations, and grey water and rain-water recycling are of the other environmentally sensitive characteristics of the building.

The LEED Platinum Certificate winner project is an integrated design effort, coordinated down to the last detail with experimentation and study based on design / development methods and encouraging the use of local resources and materials and thus contributes to one of Turkey’s strongest and most traditional industries.