By Candace Sofianos King | Photos by Henton Homes

Meet House Verster, a contemporary sustainable home with true grit.

For any builder, constructing an eco-friendly structure on a steep site can be a slippery slope, so to speak. However, it was a challenge for the team that worked on House Verster, a sustainable abode nestled against the mountain side in Lakeside, Cape Town.

At a cost of about R2.5-million, this ‘hybrid’ house was designed by architect Jacques Cronje of Jacques Cronje Timber Design and engineer Deon Botes of Poise Consulting Engineers.

The home is situated on a 60-degree slope and consists of 90% timber frame with the use of a steel portal frame as the main structural element.

“The site is extremely steep, but we saw that as a welcoming challenge,” says Horton Hunter, owner of Henton Homes, the Cape-based construction company behind House Verster. “It’s perfectly fine to have a difficult challenge to overcome as after exploring many options and iterations of a design, the reward is that much sweeter once you’ve come up with the appropriate solution,” believes Hunter.

Intricate green design

House Verster’s eco-consciousness and spatial design savvy is quite impressive – natural materials were used as much as possible, leaving much of the relatively steep site, with minimal level area, available for gardening. To maximise the use of the steep site, while having a minimal footprint, the house was conceived as a series of staggered levels cascading down the site, highlights Hunter.

He continues, “Even though it is relatively small in area, its home to four different internal levels each connected to the next by half a flight of stairs, so one never really feels like they are moving from one storey to a separate upper or lower level like in a typical double storey home.

“The floor to ceiling heights in each section are also vastly different; for example, we’ve used volume rather than floor space to achieve a sense of spaciousness in the living area, whereas the kitchen and bedroom above boast low ceilings, yet retain a sense of spaciousness by being open to the living area large volume – so varying volumes contribute to the spacial quality more so than the plan layout.”

The finer details

A key structural element and architectural feature of the project is the use of a large rammed earth wall that provides mass. The roof forms part of the steel portal frame so all the structural and bracing was done within the portal frame.

“Due to the project’s proximity to the coast, we used IBR corrugated AZ200 sheets and insulated the roof with 135mm Isotherm between the purlins and double-sided radiant shield sisalation [reflective foil insulation]. The ceilings were done with 12.5mm rhino board and fully skimmed.”

Apart from timber, conventional concrete foundations and brickwork for the bathroom and garage substructure was used. To ensure the structure has a minimal impact on the site, a steel portal frame structure on concrete pads was implemented. The house also includes a rib and block slab for the garage, timber framing for the rest of the building coupled with a variety of cladding including timber, corrugated metal and fibre cement.

Fast facts

  • Waterless composting toilet
  • Solar hot water
  • Provision for rainwater tanks for water harvesting
  • Highly insulated
  • Double glazing throughout
  • Provision for a green roof
  • Rammed earth wall for thermal storage

House Verster in review

  • Location: Lakeside, Cape Town
  • Site area: 580m²
  • House area: 89m² over four levels
  • Total budget: ± 5-million (including land – R720 000)
  • Construction commencement: September 2015
  • Materials: lightweight structural steel frame, timber walls, corrugated iron roof sheeting, rammed earth wall, concrete slabs for bathroom and garage floor
  • Foundations, concrete garage and bathroom floor: three months (October to December 2015)
  • Steel frame construction: one day (24 February 2016)
  • Timber frame construction and infill: two months (early March to early May 2016)
  • Rammed earth construction: seven weeks (May to July 2016)
  • Occupancy: November 2016