The Aloe House in Port Elizabeth has been inspired by its unique natural surroundings and embodies a holistic approach, using recycled materials and passive design.

Aloe house, owned by Gerda Coetzee and Eric Offerman, overlooks Baakens Valley, the backbone of some of the natural green corridors in the Nelson Mandela Bay Metro (NMBM).

Lead architect Jan Klingner found inspiration in the bold way in which the aloe ferox rises above the thicket. He used this as a design concept for the house on the edge of the valley.

After Klingner put forward three proposals, Coetzee and Offerman opted for the least conventional design, giving rise to The Aloe House’s unique geometry, which follows the distinctive shape of two aloe leaves ‑ a design that is both aesthetic and functional.

“During an extended planning phase the focus shifted to a much wider understanding of sustainability,” says Klinger. “Green building has become trendy of late and it shouldn’t be about an absolute or a dogma, but rather it is a process of negotiation to achieve a product which is long-lasting beyond just the green aspect.

As well as incorporating aesthetic expression and green technology, the house is laid out to satisfy various future scenarios including different family structures, the presence of nurses and even the further densification of the built fabric.

 

Passive design and efficiency

With Port Elizabeth’s mild and relatively constant climate and short heating and cooling periods, thermal mass is employed to regulate the building’s temperature. Massive lateral brick walls serve as a heat sink, evening out temperature differences. With a highly insulated ceiling, this ensures minimal heat transfer.

Double-glazed windows on the northern aspect of the house trap solar radiation during the winter months, and an insulated slab covered by dark stone tiles provides sufficient thermal mass ensures heat is radiated back into the house during the cooler nights and early mornings.

During summer, the glass front is shaded and the double-glazing keeps the heat from the external environment out.

Two pumps heat the water, and in addition to their efficient energy use, they eliminate peak loads associated with conventional geysers or solar water heating backup elements. This is an important aspect that has been considered for the planned installation of solar photovoltaic (solar PV) energy later.

A split distribution board, built-in reticulation, LED lighting and a gas stove will also ease the adoption of solar PV power.

Energy efficient appliances are used throughout the house and the swimming pool is solar heated.

“Rainwater is collected off the entire roof with a total storage capacity of 25 000L and is used for watering the garden at this stage,” says Offerman.

Grey water is collected through separate piping and is also used for irrigation.

 

Materials and structure
More than a third of the bricks used for paving around the house consist of material recycled from the dismantling of a kiln. Some of the feature timbers used for decking, stairs and handles were also recycled from the old brick factory.

“Even though the building was constructed from conventional materials such as brick, reinforced concrete and timber, the applications were unconventional and many challenges had to be overcome,” says project structural engineer on the project, Ivo Huisman.

“One such challenge was the roof structure. The roof design is for a very lightweight timber structure supporting different facetted planes. The innovative timber roof frame is connected with numerous structural steel brackets designed to accommodate the complex three dimensional form and necessitated some good teamwork.”

 

Biodiversity and landscaping

The Aloe House garden, some sections not even a year old, is “a garden in the making,” says Coetzee. Coetzee cultivated and collected plants and trees for more than three years and landscaped the approximately 1 500m2 garden on her own.

The garden is a rich collection of indigenous plants; many of them rare species salvaged in old brick fields. “Pride of place is given to 12 types of Eastern Cape aloe, including endemics such as A.

micracantha, A. lineata and A. speciosa. Gasteria acinacifolia grows near the entrance to the front section of the garden,” says Coetzee.

Thirteen different Eastern Cape trees, including three types of Cussonia, one of which is the rare Gamtoos cabbage tree, already grace the garden.
“The aloe-shaped geometry of the building is a bold acknowledgement of the surrounding vegetation and important role that aloe ferox plays within it,” says Coetzee. “We are completely in love with our own home.”

 

The full feature appears in the April-May 2014 issue on page 24. Images by Wianélle Brier.