House in Forest Town - improving climatic performance of a heritage house on a hill 

          Client: private
          Status: complete
          Budget: R2 million
          Services Offered: full suite
          Original design: Italo Carlo Lupini, 1986

This house was completed in 1980s by Lupini Architects. It is an architectural and engineering wonder. The house is terraced into a north-facing (maximum solar exposure) ridge with views all the way to Pretoria and the Magaliesburg on clear days. 

The plan is simple: rooms open off the central double-loaded
circulation spine. In section, this circulation spine is a straight stair that rises five storeys. It is roofed by a skylight. Every room has a northern exposure, corner windows that slide into the cavity wall that frames them and access to the rooftop of the space below.

My intervention was to reinforce the house’s purity (a strong connection to the hill and outdoors) by improving its climatic performance.

I therefore focused my energy on the glazed stairway, the roof platforms and the hill.

The glazed central stairway was conceived as a climatic conservatory. (I retained the existing structure, but replaced the glass). The poor insulative property of the glass roof was exploited by installing operable openings. In winter, the openings can be closed and the glazed stairway space allowed to overheat like a greenhouse and simultaneously heat the attached cooler rooms of the house by convection; in summer, the glazed stairway is opened and thus cools the adjacent rooms of the house.

The roof platforms were landscaped to allow usage and improve the thermal insulation of the rooms beneath:
One roof platform was flooded to become a moat / roof water garden. This feature has security, insulative and aesthetic functions. Another platforms were planted to support pickle ball and putt-putt, a third becomes a zen garden while another became a deck for sun tanning and entertaining. The roof of the second bedroom accommodates the solar panels.

When built, the water table on the hill was traversed by the construction of the retaining walls that support the terraced platforms that characterise the house. I saw this as an asset rather than a problem. We installed agrcultural drains to channel the groundwater away from the structure and into the new water storage tanks that are placed in the lowest point of the house - the driveway - and planted water intensive trees to further drain the soil. Water is also used to aid the evaporative cooling of the glazed stairway