Construction World October 2017

designed using specially rolled corrugated steel cladding. Energy efficiency Fifty mm high-density polystyrene was inserted between the floor joists, contributing an R-Value of 2,083 m 2 K/W to the floor, already exceeding the minimum requirements of a complete suspended floor in Climate Zone 2. The 18 mm shutter ply and 22 mm solid timber floors contribute further to the R-Value of the completed floor structure. Exterior walls were tightly packed with 102 mm cavity batt insulation with an R-Value of 2,68 m 2 K/W, also exceeding the minimum requirement for Climate Zone 2. The R-Value of softwood timber is approximately 0,05/mm and, with the exterior cladding being 50 mm with an average thickness of 25 mm, the cladding carries an R-Value of 1,25 m 2 K/W. The 8 mm OSB board has an R-Value of 0,46 m 2 K/W and the 15 mm internal gypsum board has an R-Value of 0,071 m 2 K/W, making the collective R-Value of the peripheral wall +- 4,5 m 2 K/W (the additional air barrier has not been taken into consideration into the calculation). The roof insulation consisting of 50 mm high-density polystyrene with an R-Value of 2,083 m 2 K/W and 50 mm Lambdaboard insulation with an R-Value of 2,08 m 2 K/W make for a total R-Value of +- 4,163 m 2 K/W for insulation, exceeding the minimum specifications for Climate Zone 2.

Bronze aluminium windows and doors were installed throughout the house. All glazing was coated with low-e film per the architect’s specifications and energy efficiency calculations done according to national glazing

standard specifications. On point, off grid

Per client requirements, House du Preez was built off the grid with water supply from a borehole powered by a solar panel. Electricity is generated via photovoltaic panels, which charges a battery bank with power converted to 220 V by a 3 kVA inverter. An energy efficient pressure pump was installed with a slow start-up and shut-down control system. Water is heated using gas, which also powers the stove and oven. All the lighting is energy efficient LED lights and household appliances are all AAA-rated. While the project offered up its own unique set of challenges to the Eco Log Homes team, including no on-site accommodation, limited accessibility and especially rugged terrain, the beauty of the Boschhoek Mountain Estate more than makes up for this. With its magnificent vistas, abundant wildlife and distinct aromas rising from the veld to tell stories long forgotten, House du Preez stands proud – and yet humbly – an ode to the landscape upon which it sits and very much a part of it.

sustainable construction world

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OCTOBER 2017