The Sustainability of Nina Maritz
Maritz honed her design skills and established her practice through several small institutional projects. But winning a competition to design the Habitat Research and Development Center in Windhoek, Namibia gave her the opportunity to more fully apply her sustainable design philosophy.
Study in Habitat
The purpose of the center is to research and promote sustainable strategies for housing. "We started from the metaphor of a pangolin [similar to an armadillo]" Maritz says, "where overlapping scales protect against predators, in this case the harsh climate and environment... it opens the vulnerable inside to the streambed."
Building wings of the Habitat Research and Development Center stretch east-west and open to the north — facing the sun in the southern hemisphere — to take advantage of the predominant wind direction and to maximize daylight. Like any good architect, Maritz looked for opportunities for efficiency in the facility's program. Instead of building the large gathering area inside, for instance, she made an outdoor amphitheater, shaded but open to the breezes.
In the hot, arid climate of Namibia, cooling is the primary thermal comfort concern. One of the most distinctive features of the center's design is the evaporative cooling system. Rainwater, which comes in infrequent deluges, is collected in tanks and sprayed through misting nozzles; the air cooled by evaporation falls into the building.
Like the ventilation scoops sometimes found in Middle Eastern buildings, the butterfly roofs of corrugated steel capture wind and act as stack ventilators. They have also become a design emblem for the center.
Another ingenious cooling device explored in the project is what Maritz refers to as the "traditional farm cooler." This system is made of a cavity wall of offset bricks allowing wind to pass through. The cavity is lined with wire mesh and filled with chunks of charcoal. Water is slowly dripped along the top, wetting the charcoal enough to create evaporative cooling as air moves through the wall.
Materials of the Desert
The architect chose a basic palette of materials that reflects vernacular building strategies. The traditional Namibian house is a circular wattle and daub (mud and straw) structure with a conical thatch roof. Like the Pueblo Indian dwellings of the American Southwest, the massive walls store "coolth" from the mild desert evenings. Maritz used both rammed earth and brick construction in the massive walls of the research center.
The design is also a good case study in integrating natural materials into a contemporary building. Avoiding imported timber and precious local hardwoods, Maritz specified poles from invasive tree species. Reeds form the horizontal and vertical sunscreens and shades for openings throughout the facility.
Thin reeds are also used on the ceilings as a decorative feature and to support a layer of natural batt insulation made from low-grade sheep's wool and lavender to discourage insects. Insulation is most important in the ceiling to reduce the amount of heat from the relentless sun that conducts down from the roof surface.
For retaining walls, the architect developed a variation on the "earthship" model of reinforcing stacks of spent auto tires with compacted earth and rebar. Where a more uniform texture was needed for the building walls, the tires were cut into quarters, and those smaller pieces were used to fill in the gaps.
Another important commission for Maritz is the Visitor Center for the Twyfelfontein Rock Art Museum, a facility meant to protect and make accessible ancient stone paintings.
She explains: "In the dry northwest of Namibia, famed for its variety of rock landscapes, the challenge was not to obtrude and compete with the engravings... but to design in such a way that [the structure] would become one with the landscape."
This empathy with the surrounding landscape was expressed in part through material choices. The iron content of the local sandstone gives it a rusty red color, so the design team selected modified steel drums as a roofing material, making "a building that will rust away very slowly" in the extremely arid climate.
The roof cladding was made of 40-gallon (150-liter) steel drums cut vertically into quarters and lapped like clay roof tiles. The paint was sanded lightly to begin the rusting process. The tops and bottoms of the drums were used to form screening walls.
The undulating roof form emulates the weathered stone hills nearby; from a distance, a visitor might not realize the distinction. The curved steel frame was manufactured on site by a "farmer-builder who made a jig on his pick-up and bent every curve by hand."
Because water would have to be trucked in, the design team made the decision that the construction process would be "waterless" and not use materials such as mortar or concrete. Gabion walls consisting of dry stack stone stabilized by a casing of chain-link mesh — also hand made on site — formed the heavier structural elements and foundations. Because no concrete was used, the building is completely "reversible" and removable.
"Less is more... perhaps one can say that in Namibia and other desert countries," says Maritz. "Learning to live with the absence of water makes it more precious and significant, and one has to be more inventive in dealing with it. For myself this is starting to result in a kind of frugal design — one can maybe call it scavenger architecture. The 'less' in this case is not the less of Miesian minimalism, but the less of means, in which poverty of resources can lead to richness of expression."
When agonizing over getting the most out their projects, practitioners and students of architecture in the rest of the world would do well to think of this humble architect toiling in the Namib desert with little more to work with than her wits and the wisdom of traditional peoples. Sustainability is a way of thinking about the world and not just a series of line items on a spreadsheet.
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Michael Cockram is an adjunct assistant professor of architecture at the University of Oregon. He is the director of the Italy Field School Program.