When master builder Keith Bergh stumbled upon a hillside property in the village of Hoekwil he knew he had found the perfect place to build a home. But the agent told him not to bother; many prospective buyers had tried and failed to buy the plot overlooking a nearby ravine. Today, a modern eco-home stands on the site.
Keith Bergh is pleased. He has completed the first few legs of his alternative living journey, and is in the operational phase of his home.
“I get people passing by and stopping because they see the solar panels on my roof,” he says. When they see his alternative lifestyle, they ask him what he needs that is not produced or generated on the plot. “The only thing is meat, because I won’t kill my cows,” he usually answers.
An established permaculture vegetable garden provides fresh produce while a chicken coop offers free-range eggs. What is not produced or generated on the property is traded with neighbours.
“The design had to be simple enough to enable Bergh to owner-build with the help of an unskilled local workforce,” says Johan Moolman of Moolman Associates Architecture. “It is an L-shaped timber structure with a mono pitched steel roof.” The roof was specifically designed to host 15 solar panels.
“The house has two bedrooms and a large central open space living area, which leads onto decks,” he says. Taking the local climate into consideration, “a second large timber deck to the north-west mitigates the south-easterly winds”.
Architectural features blend well with local materials; over the central living area, exposed rafters meet the valley beam at a maximum height of 4.5 metres.
This fairly isolated plot had no municipal services or Eskom electricity. To show for it, the basement hosts a water catchment, filtering and piping system, which secures continuous water provision.
A combined 45 000L of rainwater is stored in the basement. “All the rainwater collected from the building’s roof via all the gutters drain into a piping system, which flows to the sediment filter tank in the basement,” explains Bergh.
When full, the filter tank overflows to a secondary set of tanks, while the filter tank itself is flushed every few weeks via an outlet pipe. “From the secondary set of tanks, the water is pumped through two carbon filters for purification,” says Bergh.
“The water system makes use of a pressure tank. It saves the pump if you use only a little bit of water in the house. The electric pump won’t turn on until all the pressure is out of the tank. It slows everything down, and is lighter on the energy and pump systems,” says Bergh.
For hot water, a gas burner is used, processing 26L per minute.
A 300 000L capacity dam fills up from the property’s storm water. An aquaponics project is planned for the dam. Linked to the dam are three shale pools, a feature that filters the water via natural plants and aeration. The water circulates between the shale pools and the dam, driven by a solar pump with a capacity of 34 000L per hour.
The renewable energy system comprises fifteen 250W Renesola solar modules, installed on the house’s roof, and two 60 Amp charge controllers, 24 Msolar 1380Ah deep cycle cells and a Victron Multiplus 5kW inverter.
The PV system installed “will allow energy security for the next 25 years”, says the project’s solar consultant, Div de Villiers of ALLSOLAR Garden Route.
“This system is generating 15kW per day at the moment,” says Bergh. “We’ve calculated that if all the electrical equipment in and around the home ran, I’d use 12kW per day.”
Energy from the solar modules is stored in a deep cell battery bank, with a combined storage capacity of nearly 54kW. “The fully charged battery bank will provide the household’s energy needs for up to three days if the weather is not favourable for energy generation,” says De Villiers.
Bergh calculated that the PV system would be paid back in seven to eight years.
A Victron battery monitor and Efergy Engage Remote Energy monitoring system have been installed.
Structure and materials
“About 70% of the house is constructed from waney board,” says Bergh. Besides being a local product, these planks require no processing other than saw cutting.
Building regulations required 50mm insulation, but they’ve doubled the insulation to 100mm to minimise energy loss.
Throughout the house, the flooring benefits from a sealed finish.
Many of the materials for the house were dug up or traded. “When Eskom replaced the power line timber poles with steel structures, they offered the poles to farmers at R6 per pole. The farmers wouldn’t let go of them,” says Bergh. Eventually, he traded a neighbour the labour and construction of a natural swimming pool stone wall for 23 timber poles. Thirteen poles are used in the house, and ten on the facade.
The full feature appears in the October-November 2014 issue, page 26. Photography Melanie Mare.