A Green Getaway: Cape West Coast: Architural Digest SA Print E-mail

Published in Architural Digest South Africa 2001
A Green Getaway – Cape West Coast
: Architect/Designer: Andy Horn of Eco Design:

Introduction

The typical holiday house is built at great cost to both client and environment. This project utilizes a combination of local natural materials, recycled elements and non-toxic finishes. The result is an environmentally friendly house that is both energy and water efficient

 

Brief

The brief was to design a traditional Cape style “longhuis” on the old stone base of an existing ruin, which would be in keeping with that of the surrounding farm buildings. The house was to be used as a holiday getaway for client and friends from Johannesburg. The clients’ request was that the house be built as simply and inexpensively as possible and specifically, that it makes use of straw bale building technology.

Site

The farmer had leased the client an old ruin at the edge of his farm. It sits parallel to a wide river vlei with its back to an array of sheds, farm buildings, Cape style farmhouses and old ruins. The site looks out across limitless tranquil waters and enjoys spectacular sunset views across a distant mountain headland and glimmering sand dunes.

 

Layout

An arched fanlight punctuates the front door, which leads into the middle of a long barn-like space. The fireplace buttresses the kitchen gable wall while the opposite end of the space leads to the bathroom and bedroom level.

The open thatch ceilings and the open-plan living/kitchen spaces bring a light, airy modern feel. This contrasts with the sense of timelessness and endurance created with the usage of second hand doors and windows, thick walls and solid stone piers.

A second hand teak and glass paned door leads from the living area out onto the terrace’s breathtaking views. A pergola (as yet to be built) is to cover a part of the terrace and will support deciduous vines, to help provide welcome shade during the harsh summer months.

The bathroom opens into a curved bamboo reed screen, which clips on to the side of the house, creating a private courtyard with an outside shower. A new doorway at the gable end of the bedroom, opens out into a private bedroom courtyard.This is edged by a portion of the ruin, which has been retained to form a bridge between old and new.

Super-structure

There was very little of the original mud brick and thatch roof “long huis’ worth saving, except for its sturdy stone foundation wall. This was raised up and leveled as a base for the straw bale walls. The load bearing structure is then clearly expressed with a series of hefty stone pillars. The pillars are tied together with thick poplar poles supporting a long thatch roof. Together they create an ordered rhythm and a sense of intimacy within the free flow of the open plan.

Poplar pole columns stand on the raised stone foundation wall, supporting a horizontal eaves beam. The beam runs the length of each long side of the building to support the ends of the rafters, while creating a sturdy framework into which the bales are stacked.

Straw Bale Phenomena

Straw bale buildings originated in Nebraska, USA and have been around for over a hundred years, but it is only in the last decade that the technology has caught on worldwide. Straw is an annually renewable agricultural by-product. Straw bales offer superb insulation, both thermal and acoustic and are both fast and cheap to build with. These walls are surprisingly fire proof, as a straw bale possesses insufficient amounts of oxygen to permit combustion. Indeed, such walls have been known to actually stop a fire from spreading.

As in traditional straw bale buildings, solid footings elevate the bales off the ground and the roof overhang helps protect the bales from damp. Similarly, the lime-clay based plaster and paints allow the walls to breathe.

Cob* was used to fill all the gaps and sculpt the splayed reveals** around the openings in preparation for the lime and cement plaster

Environmental performance

The house is well sheltered in its positioning and shields the Terrace from the strong southeasterly winds.

The phenomenal insulation of the straw bale walls and thatch roof, combined with good cross ventilation result in a building that enjoys excellent levels of thermal comfort. Indeed a lasting memory of the finished house is of a blissfully cool retreat away from the searing heat of the West Coast sun.

Low Environmental Impact

This project consumed a negligible amount of embodied energy ***

Where durability was an issue, a small number of clay fired bricks – being relatively high in embodied energy – were used to build the chimney and inner bathroom walls. The remaining walls are made of straw and mud. The straw was baled on a neighbor’s farm. Mud bricks were salvaged from the ruin and reused in the living and kitchen gable-end walls. Some of the mud was also re-mixed as cob. *
All the poles were treated with Totim-B (a non-toxic, mammal friendly, timber preservative), which leaves the wood its natural color. Using this product allowed for some of the poles to be sourced and treated locally, reducing financial and transport costs while promoting local job creation.

All the doors and many of the windows sourced were second hand. To avoid being party to the deforestation of tropical rainforests, no new hardwoods were used. The new windows were made up specially, using selected second hand Oregon and local pine timbers only.

In terms of services, grey-water irrigation and the waterless Enviro-loo composting toilet help conserve water.

The floors were laid with a locally sourced slate, hewn into shape on site. The slate was laid onto a thick-leveled screed on well-compacted earth. In the bathroom the floor has been in-laid with seashells.

In Conclusion

This project demonstrates how, by building in greater harmony with nature, a high standard of building can be achieved with minimum means.

 

Footnotes:

*Cob: also known, as “opgeklei” is a mixture of clay and straw built layer upon layer.
**Splayed Reveal: the chamfered side of a wall around an opening.
***Embodied Energy: the total sum of fossil fuels (coal, oil, gas, petrol etc.) burnt in a products extraction, manufacture, transport to

 

 
Nieuwoudtville Award

Eco Design Architects was awarded the Holcim Award for Sustainable Construction 2005 & took silver in the Africa and Middle East Region for their designs for the Nieuwoudtville Caravan Site Upgrade

Click here for more info on the award.

 

Mamre Revitalization Project is an initiative by the City of Cape Town to promote the preservation and restoration of Mamre’s rich heritage resources, while helping to alleviate poverty and promote skills transfer. Eco Design Architects have been appointed by the city to assist the community with this project. Click here for more info or go to Mamre Revitalization Project Website