The traditional gabled roof that we are all familiar with was engineered to slough off snowfall. But in an uncertain post peak oil future of possible energy shortages and water shortages, more and more houses are showing up with roof-shapes engineered to harvest their own rainwater, and support solar power generation.
This creates a butterfly roof, the opposite of the traditional gable. Kangaroo House in increasingly drought ridden Australia has the same distinctive roof shape, for the same reasons.
This design for a zero energy house on the coast of the Brazilian rainforest features such an inverted gable roof, designed to funnel and centrally harvest its own water supplies for the entire year. This coast of Brazil provides abundant rainfall from January to July.
The huge roof also is also designed to maximize solar energy production on top and to funnel cooling breezes throughout the open plan holiday house, so as to eliminate the need for airconditioning.
Tropical areas such as Hawaii have utilized the Butterfly roof to harvest precious rainwater since the middle of the last century, but these new ones are angled at the steeper 20 to 30 degree angles that are needed to maximize solar production.
With the steeper angle the tropical downpour is also more efficiently harvested in the roof’s center rain-funnel shape, where it is then filtered, stored and pressurized to the tap. The energy generated from solar panels on the roof, and hydraulic, gas and telecom services run in two vertical cores accessible from the bathrooms and kitchens for maintenance. This simple coastal location is far from a public sewage system, so a septic tank with a super efficient anaerobic filter cleans up to 90% of the effluent.
The clients of the Camarin Architects wanted a simple holiday house with three bedrooms that allowed wide possibilities of contact with nature. Both the wooden skin that envelops the gallery and the suspended roof, shelter the house from the Sun while keeping it permeable to the cool South wind, to avoid the need for air-conditioning.
Passive cooling is achieved the old fashioned way with wide verandas, and a gallery open to the elements and sea breezes, to shelter the interior spaces from the tropical sun. The wooden skin that wraps the gallery filters the glare, providing intimacy in the bedrooms, shading the interior while framing the views outward.
This design creates its own cool micro-climate during the dry season. The self-sufficiency of the house is unprecedented in the region.
Photography by Nic Olshiati
First published at GreenbuildingElements