Getting High Design from a Low-Tech Approach  

While architecture magazines are saturated with images of soaring, wriggling towers and pristine, jewel-like structures, those buildings represent a small fraction of actual construction. Most of us live, work, and play in very conventional buildings-traditional wood-frame houses, steel-and-brick high-rises, concrete-and-glass shopping malls. And for much of the world's population, the comforts of home-not to mention work and recreational facilities-are critically lacking. Governments around the globe are increasingly looking to architects to address the housing and infrastructure needs of impoverished communities, in the process hoping to improve the grim economic, educational, and security conditions that plague them. The resulting structures are almost always the antithesis of those complex, computer-driven designs that typically grace these pages. Because of limited financial resources, these projects rely on a low-tech approach using simple forms; local, unskilled labor; unusual or recycled materials; and alternative construction methods.

Building community

Colombia has long been seen as a country where the rule of law does not exist. The armed conflict there-between left-wing guerrilla groups, right-wing paramilitaries, and the national police-is the longest-running conflict in the Americas. Drug production and trafficking, violent street crime, and kidnappings only add to the brutal way of life to which many Colombians have unfortunately become accustomed. But recent government efforts to build public spaces and educational facilities in disadvantaged areas have markedly improved living conditions for residents.

Following a large discovery of crude oil in the early 1990s, the Casanare region in the northeast part of the country has enjoyed an economic boom. Wanting to share some of its newfound wealth with the people (and taking a cue from construction efforts in Colombian cities such as Medellín), the regional government embarked on a plan to populate its cities with libraries. The first of these was completed last year in the town of Villanueva, a 5-hour drive from Bogotá.

A boxy structure is finished with simple materials in a public library in Villanueva, Colombia. Photo © Nicolás Cabrera Andrade

 

The job of designing the library was given to four recent architecture school graduates-Miguel Torres, German Ramirez, Alejandro Piñol, and Carlos Meza-after collectively winning a national competition, their first. "We wanted the building to have a strong signature, and be very clear in terms of materials and shapes," says Meza. The designers could not have chosen a simpler material palette-quite literally sticks and stones-employing them to dramatic effect in a 16,700-square-foot rectangular structure that incorporates an outdoor plaza.

Though the concrete frame was poured on-site by a professional crew from Bogotá, much of the subsequent construction was carried out by residents of Villanueva and nearby towns, following workshops that taught the locals basic building techniques, as well as the unique methods used for this library. "This is a post-conflict area," explains Piñol. "People who are no longer engaged in violence are being reinserted into civil society. This was a way to do that."

A distinctive feature of the building that required special training to construct was the gabion wall. Nothing more than cages of rocks, gabions are more commonly used in civil engineering projects for erosion and flood control. For the library, experienced road builders from the region were brought in to supervise their assembly in 12-inch-deep wire cages along the entire 234-foot-long eastern facade. Workers experimented with the look of bisected stones in some sections of the wall, but opted to keep the rocks intact-mainly because it was less time-consuming that way. Also within the wall are four unglazed openings that feature aluminum, microperforated louvers for increased ventilation. The 31-foot-high wall wraps around the north and south elevations, as well. "Most people approach the site from the east," says Piñol. "We wanted to communicate a solid building, especially in a town that has no architectural icons whatsoever."

The small stones, which average 4 to 5 inches in diameter, were collected from nearby rivers. For the opposite side of the building, which contains a covered, outdoor space for public gatherings, the designers chose another local product. Dimensioned pine-wood pieces from regional, controlled forests are arranged in a playful pattern in modular panels that make up the wall and overhang of the plaza. "The choice of materials was intuitive," Meza says. "Even though we hoped to create a monumental building, we also wanted it to convey a local, crafted product."

For many of the library's reading, media, and meeting rooms, this lattice of sticklike pieces of pine is all that separates the interior from the exterior. Unlike Bogotá, whose mountainous terrain has a cool climate, the flat landscape surrounding Villanueva features an almost tropical one. Enclosed spaces include restrooms and a ground-floor theater, which is the only room that uses mechanical cooling.

Earthquakes and heavy rainfall characteristic of the region presented challenges to the builders. To conform to seismic regulations, foundations for the two-story building are more than 61⁄2 feet deep. Each of the columns that supports the plaza's canopy-left bare to align with the clear expression of materials throughout the building-contains pin connections at the top and bottom to allow lateral movement.

Giving equal attention to unbuilt space, the designers created a 27-foot-wide outdoor plaza for public gatherings. Photo © Nicolás Cabrera Andrade

 

The downpours typical of the rainy season are handled in the building by another striking feature, one that is concealed behind the parapet of the gabion wall. A zigzagging roof-sloping down in a west direction over large program spaces, and east over 6-foot-wide corridors-distributes rainwater to channels on both sides of the building.

A particularly oversize gutter on the west side also collects runoff from the sloping, trussed roof over the plaza, which consists only of a polycarbonate sheet less than 1⁄2 inch thick. The main roof is composed of a sandwiched metal deck, whose inner glass-fiber layer helps buffer the sound of falling raindrops.

	  To conform to seismic regulations in this earthquake-prone region, foundations were dug 6.5 feet deep (left). Stones collected from nearby rivers are encased in PVC-coated wire (below left). The west facade is composed of panels of sticklike pieces of pine arranged in a slanted pattern (below right). Photo © Alejandro Piñol/Mariana Bonilla Â
1. Outdoor plaza 2. Theater 3. Circulation

 

The alternating slopes of the main roof provide other benefits, as well. The raised, east-facing portions over second-floor stacks and reading areas are glazed to admit daylight. These areas also aid natural ventilation by drawing hot air up and out of the building more readily. "We wanted the building to be fresh and authentic, not a showoff," Piñol recalls. "We designed it in the most honest and direct manner we knew how.

Gimme shelter

Across the globe in Cape Town, South Africa, a local firm, MMA Architects, recently completed the first of a series of houses it is building in Freedom Park, an area which, despite its hopeful name, is a crowded shantytown within the Mitchell's Plain Township, and which until a few years ago lacked basic infrastructure such as plumbing and sanitation. MMA's project is part of a larger initiative by a charitable trust to build 490 units of affordable housing there. The price tag for the first house came in well below $10,000 and is expected to go down even further once mass production begins.

	  A housing project by MMA Architects in Cape Town, South Africa, was conceived as a starter home to be expanded as occupants are able to afford it. An upper terrace and a large rear garden provide space for extensions. Â
	Sand is a cheap, durable, and easily obtainable building material. In this flood-prone area, foundations for the house are lined with sandbags. Photo © Wieland Gleich
Walls of sandbags offer excellent thermal and sound-absorbing properties. Photo © Wieland Gleich

 

	The sandbags are plastered over on the exterior. The bags are dampened beforehand to ensure that the plasterwork cures instead of merely drying (top). Residents of the township participated in the construction by filling sandbags (left). Photo © Wieland Gleich

 

To achieve such an impossibly low figure, the architects, led by Luyanda Mpahlwa, researched alternatives to the brick and concrete block construction that is prevalent in the region. "Architects are not involved in low-cost housing here in South Africa," Mpahlwa explains. "That is usually carried out by developers with government subsidies. Without any sense of creativity or innovation, they produce a model house and then just press the repeat button. Our industry does not yet support alternative design, so you really struggle to find affordable building materials."

Mpahlwa eventually settled on a unique construction system produced by a small, local company. Composite assembly featuring a metal truss sandwiched by timber outer layers make up the floors, staircase, window openings, and exterior walls of the two-story house. The use of this kind of assembly saves up to two-thirds the amount of timber used in conventional wood frame construction. The space between the columns of the exterior walls was filled with an unlikely, but readily available product-sand.

Members of the community, particularly the beneficiaries of the 580-square-foot house, collected sand from the surrounding dunes, sifted it to remove insects and debris, and put it into bags that they stacked within the structural framework. The resulting 15-inch-thick walls, Mpahlwa points out, provide excellent thermal properties, in much the same way that traditional African stone or mud rondavels do. The walls are also fire- and wind-resistant, besides having superior sound-absorbing qualities in an area where privacy is in short supply.

The sandbags' ability to prevent water penetration offers another benefit. Much like walls of sandbags that are often assembled for flood control purposes in the wake of rising rivers, the sandbag-walled house is particularly useful in an area prone to flooding.

As in the Villanueva project, a construction manager and a small team of skilled workers oversaw construction, which included on-the-job training for locals. Throughout almost the entire building process, no electricity was required on-site. Beams were fabricated to measure in a nearby warehouse, and cement to plaster the exterior walls was mixed in a hand mixer. Concrete was used only in the beams to support the second level, where the bedrooms are located. Interiors are clad in timber board.

Mpahlwa left a considerable portion of the house's small plot unbuilt, allowing for a garden and a safe area behind the house for the recipient family's six children to play. "These are very dense and dangerous environments," Mpahlwa says. "It's important to think about issues of comfort and safety." The family, who had been living in a shack, was involved in the design process from the beginning. "They had never lived in a formal structure," Mpahlwa says. "It was an incredible feeling to see the look on their faces as they moved into their first home."

Up market

Vegetable vendors occupy many of the market's stalls (above). Compressed earth blocks, formed with a hand-press machine, were used for roofs as well as for walls (bottom left). Large arches support dome-shaped roofs (bottom right). Photo © Amir-Massoud Anoushfar (top); Laurent Séchaud (bottom two).

 

Farther north on the African continent, a government program to stimulate economic growth led to the creation of an extraordinary project. The landlocked nation of Burkina Faso is one of the poorest in the world, with few natural resources. Most of the population is engaged in agriculture (despite crops' vulnerability to periodic drought), and a large part of the male labor force migrates annually to neighboring countries for seasonal employment.

A section of the Central Market in Koudougou, Burkina Faso, reveals a series of arced shops (top). The market's orthogonal layout covers an area of 312,000 square feet (below).

 

In Koudougou, the country's third-largest city, the construction of the Central Market helped provide jobs and develop masonry skills among local workers. Once completed, its 1,200 shops-encompassing 312,000 square feet-offered a vibrant civic space for commercial and social exchange.

The market, which was honored with the Aga Khan Award for Architecture in 2007, was built under the direction of the Swiss Agency for Development and Cooperation in collaboration with the Burkina Faso government. The principal architect, Swiss-trained Laurent Séchaud, has resided in Burkina Faso since 1997. "The climate and living conditions here are quite difficult," Séchaud says, "but the people are very welcoming."

While buildings made of earth-whether rammed earth, cob, mud bricks, or compressed earth blocks-are largely alien to people in the developed world, much of the rest of the world's population occupies such buildings. The one-story houses throughout Koudougou were, until recently, built from earth blocks. Construction of these homes, along with that of the city's administrative buildings and urban facilities, is now almost entirely of concrete block and other costly, imported materials.

Designers of the Central Market, including fellow Swiss Pierre Jéquier and local engineers, reclaimed the traditional building technique, using the humble, locally made product to create a sprawling bazaar of vaults, domes, and arches.

Photo © Amir-Massoud Anoushfar

 

Compressed earth blocks provide the precision and versatility of bricks but can be made of virtually any kind of soil, require very little moisture, and do not need to be fired in a kiln-making them less expensive and more environmentally friendly to produce. Earth for the market's blocks was manually extracted from a hill 11⁄4 miles from the site. A small percentage of cement was added to the mix as a stabilizing ingredient.

The blocks were made on-site using 12 hand-press machines, each supported by a rotating staff of four workers. Up to 9,500 blocks of varying sizes could be produced per day, totaling 4 million for the entire project. Smaller blocks were used in the vaults and domes. Larger blocks measuring 111⁄2 by 31⁄2 by 51⁄2 inches filled in the walls-the longest dimension representing the wall's depth. The blocks were cured in the sun in two stages, each 14 days long.

The market's orthogonal layout mimics the colonial grid characteristic of Burkina Faso's cities. Around its periphery are shops that stay open past general market hours, animating the city center. In an effort to open up views, minimize solar exposure, and provide adequate air circulation within the dense market, the internal layout, while still linear, is quite diversified. Shops oriented east−west along the width of the market form alleys, as north−south oriented shops delineate small gathering spaces. An open, domed area supported by a series of high arches contains additional stalls.

The one-story compound incorporates 85 domes, 658 vaults, and 1,425 arches. Since timber is a precious resource in the region, most of these were constructed without the use of formwork. A few of the larger arches that required temporary support used timber, but for most, earth blocks were cut and shaped to form makeshift structures.

The labor-intensive project generated more jobs than would have been possible had concrete been the building material of choice. In the process, hundreds of local workers-many of them women-gained certification as masons, and now work as freelance entrepreneurs.