ArchitectsKUBE Architecture – Stefan Rademan, Simon Mountford
LocationCape Town, South Africa
Structural EngineerGadomsky Structural Engineers
General Contractor & Project ManagerVenture Projects
Solar InstallationSolarzone in conjunction with Florad
Text description provided by the architects. The site which is located on the southern slope of Lion’s head, within the trendy suburb, Tamboerskloof, commands spectacular views over Cape Town and the harbor. From the street one gets a hint of the building, but your first real interaction is with the timber box, which houses the guest suite, looming over as you draw near the premises. The gate leads one to a lush courtyard where granite stepping stones set in an indigenous garden guide you to the front door.
Upon entering the house you are confronted by a double volume timber screen anchored in a bed of marble. Shadows streak down the wall behind as the screen filters the light cascading in through a skylight located over the stairwell. The off-shutter finish of the concrete soffit is complemented by recycled timber parquet flooring laid in a herring-bone fashion. The brief required an arrangement of interconnectedness and it is from the entrance foyer that you can best appreciate how the spaces have been assembled in order to achieve this. The space serves as a circulation hub and access point to all the zones – the public component comprised of the living dining kitchen functions is located to your left with the garage entrance to your right. The staircase leading upstairs where the private living quarters are located, wraps around the timber screen becoming a walkway accessing the 2nd bedroom and guest suite and then a ramp as it leads you to the master suite.
The living dining component, located on the ground floor, is both versatile and durable with concrete, timber and marble dominating the palette. These materials have a reputation for maturing gracefully while the soft muted tones create a versatile canvas for interior styling. The dining space, backed by an open-plan kitchen, is set up for comfortable, generous gatherings and flows onto the outside entertainment area. The adjacent internal living space is designed more towards wintertime living. The space is cozy and introspective with the wood-burning fireplace drawing the viewer’s attention away from the views. The parquet flooring here is arranged in stretcher-bond fashion, a more contemporary adaptation of the norm.
The outside living space is flanked by the swimming pool. The predominantly summer space also lends itself to those cooler evenings thanks to the introduction of an outside fireplace. The off-shutter concrete slab which covers the space is suspended between the three massive timber-clad portals. Inserted into the slab is a walk-on skylight allowing additional sunlight to penetrate the space below. The deck structure and the main residence were envisaged as separate forms and to enhance this concept the joints between these two components are also glazed.
The dialogue between the expansive and the intimate is particularly present within the upper, private living spaces. The guest suite and 2nd bedroom which is located on the opposite side of the entrance foyer represent contrasting approaches to space. The guest suite located on the street elevation opens up to views of signal hill, extending the space into the landscape while the 2nd bedroom despite having an identical configuration is intimate and contained, living out to its own secret courtyard framed by verdant planters and a timber pergola which serves as sun control as well as a security measure.
Located over the living-dining area the master suite has an open plan arrangement. The bed nestles up to a plinth clad in marble and walnut veneer while the bath floats on a slightly elevated bed of marble. Massive sliding doors and windows bring the views into the bedroom. The soffit level inside which was restrained due to height restrictions also assists in containing the expansive space. Bookshelves and books support this homely sense of scale. The suite lives out to a deck on the NW elevation. Each of the sliding doors and shutters sit on separate racks meaning that they slide independently and can be stacked in all different possible configurations. The master suite also has a private outside shower court to the South-West from where the views of Table Mountain can be enjoyed.
The openings on the North-East and South-East are large to exploit the majestic views. To regulate heat ingress on these facades movable timber shutters which function as mechanisms for passive climate control were installed. The energy efficiency of the building achieved through the appropriate use of materials and techniques has ensured that no air-conditioning installation is required. The use of energy-efficient LED, fluorescent and low-voltage lighting throughout the house also cuts down on electricity usage significantly.
The solar installation at the Hofmeyr-Cohen Residence is responsible for all hot water intended for household use, under floor heating and the swimming pool. Solar collectors installed on the roof of the residence collect energy from the sun, which is then transferred to a water glycol mix. This energy (heat) is exchanged via internal heat exchangers to water which is stored in hot water storage cylinders. The flat plate glazed solar collectors which were used at the Hofmeyr-Cohen residence was chosen due to their high efficiency in the low operating temperature range, and is especially suitable for regions with high solar exposure and frost.
In a thermo siphoning system the heated water is transferred from the collector to the tank through convection. For this to work the storage tank needs to be installed higher than the solar collector otherwise natural convection cannot occur. At the Hofmeyr-Cohen residence it was necessary to consider the sightlines and views of neighbouring properties which meant that the tanks could not be accommodated on the roof where the collectors are. Instead the tank is located on the ground floor in a storage room behind the stairs, which means that a controller and pump was necessary to transfer the heated water to the tank. The pump and controller are both connected to the main power supply and have an average consumption of around (250-300 W/day).
The client, who was exceedingly involved throughout the process, played an essential role in the success of the project, with the interesting spatial qualities emerging from a three-fold exchange between the particulars of the residential typology, the continually evolving brief and the architects’ attitude towards the creation of form.