A Johannesburg-based businessman wanted a house that would continue to operate even if the Johannesburg City Council failed completely. But this house went far beyond the brief.

 In 2008, Ivor Jones was planning to replace his house with a dream home. Eskom’s planned rolling blackout programme was introduced at the same time, which greatly influenced Jones’ brief. As a result, he asked architect Ken Stucke of ERA Architects to design a home that could operate independent of external service providers.

Stucke and his team decided to extend the brief to include all the environmental factors of building and operating a home.

“We managed to convince him to regenerate the natural environment and the site area,” says Stucke. “Most importantly, we managed to come up with a design where the performance of the house generated the aesthetics.”

 

Reducing waste

All re-usable materials from the original dwelling were saved and donated to charity, Stucke says, referring to all electrical and sanitary fittings, windows, doors cupboards, roof coverings and timber.

“The excavated masonry was crushed on-site and used as backfill under the paved areas and the house,” he adds.

The site context, climate and available materials then guided the design. “The north-facing slope, on which the house was going to be built, was an important factor in the design as it allowed the house unhindered winter sun,” he says. “The other important element was stones that were available locally.

“We wanted to build a house that would last forever but also be part of its surroundings.”

 

Micro-climatic bubbles

House Jones is surrounded by various bubbles of external space containing modified micro-climates. Each living, relaxing or entertainment area of the house opens onto its own micro-climatic bubble.

The exposed concrete slabs act as thermal mass to control climate inside the house. Heat is absorbed during the day and released at night. Cavity walls and insulated floors as well as double-glazing for doors and windows were used to guarantee maximum efficiency.

All doors and windows open outwards to ensure an airtight seal and easy waterproofing. Windows on the south side of the property have deliberately been kept small and high, while the sun-facing north side is almost entirely made of glass.

As part of the summer cooling strategy, evaporative cooling systems on top of three large chimneys provide low-energy active cooling. In winter, heat is provided by solar-powered, water-based under floor radiant heating.

A second, green envelope around the house creates micro-climates.

“The plants and flowers that form part of this envelope have been selected for their individual contribution,” he says.

The micro-climatic bubbles are cooled by mirroring the three stone chimneys for interior climate control with three “green” chimneys for exterior climate control. These were created by guiding climbing plants through a steel structure. Hot air is cooled down while rising through the vegetation.

“The green chimneys are fitted with atomiser sprays which induce an evaporative cooling effect until it becomes a falling column of cool moist air,” Stucke says.

 

Wise water usage

Water security is ensured through a borehole and capturing rainwater in four 10 000 L tanks on the roof.

The only potable water brought in is diverted to three special taps in the kitchen and bathrooms. A bypass has been created to ensure that, should the property’s natural water resources be exhausted, municipal water can be used to feed the various systems.

Solar panels warm the “heat battery” filled with 1000 L water to 950C. The system is backed up by a heat pump and gas.  This heat energy is used for domestic hot water and the under floor heating system. A small pump circulates domestic hot water so that it takes only three seconds to reach the taps.

Rainwater from the paved areas is collected directly into a 60 000 L on-site dam.

“All waste water from the house flows through a three m3 septic tank before going into an aerobic digester,” says Stucke. “From there it flows through a constructed wetlands system before it is stored in the specially constructed storage dam.”

 

Smart technology

The house uses numerous smart technologies. LED lights provide interior lighting, while various systems monitor climatic and energy performance, lights and security.

The whole house is powered by two PV arrays panels, generating a maximum of 7.5 kW. During the day excess energy is fed back into the Eskom grid and only at night is energy pulled from the grid. A diesel generator set is available should there be no Eskom power available at night.

Although the house is a showcase of modern design and technology, Stucke believes the users ultimately define the success of his vision.

He has, therefore, provided the owners with a manual with advice on how to operate the systems, adjusting their personal habits and selecting the products they use in order to limit damage to the natural water treatment systems.

Against the background of an affluent suburban area, a self-sustaining haven replicates a multitude of ecosystems proving that nature is resilient and knows how to adapt; we need only provide the opportunity.

The full feature appears in the February – March 2014 issue.