The Last Glass House
Thomashoff and Partner Architects - South Africa
Drawings, plans, elevations
The design is inspired by the rich history of Johannesburg. A key characteristic is the use of mass-manufactured steel fenestration, drawn from the presence of the galvanised steel electricity pylons a few metres away from the site. The site falls approximately 6 metres from East to West with major landscape elements, such as a massive century old oak tree, the pool, a landscaped mass of natural grass, and a landscaped earth berm. These create a series of spaces or outdoor rooms integral to the landscape with various degrees of privacy. The top terrace is a threshold space, with pedestrian and vehicle entrance and parking. The main structure is situated on the intermediate terrace, a semi-private external space that contains the swimming pool and entertainment area. The bottom terrace to the West is the most private – the double volume Bedroom Suite opens onto the garden under the large oak tree. The residential structure is 5m wide and 42m long, consisting of a single open plan space that contains most of the required functional areas. To the North and South of the main structure, the Guest Room facilities and Staff Quarters are accommodated in re-purposed industrial shipping containers. The total steelwork structure is custom fabricated. Each bolted connection, workshop detail, roof sheeting and cladding elements were designed between the engineer, client and architect. Mock-ups were constructed on site to test detailing before the structure was then manufactured and galvanized off site – the complete structure was assembled in a period of two weeks on site. Constructing this building included a fair amount of experimentation. Manufacturing and assembly marks and details were left exposed to retain the clarity and honesty of the manufacturing and assembly process. An effort was made to utilise appropriate material in keeping with its intended role and purpose. The distinct shape of the roof is emphasised by the roof cladding detail. Each roof sheet was cut at the ribs and folded over into the eaves or wall cladding, to create the appearance of folded paper. The canvas ceiling was installed as a separate floating element, to create a contrast against the exposed steel structure. No flashings were used to expose the simplicity of the manufacturing process. The design of the fenestration creates a separate transparent skin, exposing the primary structure – like a skeleton. The varying degree of reflectiveness and transparency of the glass creates a continuously changing interaction between the internal and external, structure and skin. Electricity is generated with a system of photovoltaic panels on the roof of the Guest Room that provides electrical power in the residence. The design of the roof allows for rainwater harvesting – two galvanised down pipes in the centre of the living space feeds a storage facility of 20 000 litres. Landscape design was based on Xeriscaping principles, where minimal additional watering is required to sustain planting. As a result only region-specific indigenous planting was done.