A sustainable incremental construction unit in Addis Ababa, Ethiopia is reconstructing how people think about informal upgrading. It has also received a Bronze award at the Regional Holcim Awards 2014 Africa Middle East. Here’s why.
The bi-annual Holcim Foundation Awards honour forward-thinking, innovative and sustainable construction projects around the world.
The Sustainable Incremental Construction Unit (SICU) offers an alternative for the Ethiopian housing industry. Addis Ababa, with 4.2 million citizens, is one of Africa’s fastest growing cities; and the SICU responds to this.
The two-phased project commenced with collaborative research between German and Ethiopian universities, followed by a prototype unit constructed in one of Addis Ababa’s densest informal neighbourhoods.
The unit was built on an average- sized informal neighbourhood plot. But unlike the single volume units that characterise Addis Ababa’s informal neighbourhoods, the double volume SICU could accommodate a higher population density in the same space, according to Bauhaus University’s Prof Dirk Donath, project leader and chair holder of the Ethiopian Institute of Architecture, Building Construction and City Development (EiABC).
A fresh approach
Community involvement was central in the upgrading. Driving the design and construction rationale was a desire “to make it possible for the people to build the units by themselves,” says Donath, who believes human potential should be the foundation of sustainability.
“The Ethiopian culture is one of neighbourhood and family help, financially and by shared work. It disappears in government’s mass condominium housing programmes,” he says. “SICU considers tradition and needs. It gives the local people an identity through the use of local materials, flexible housing space and incremental construction.”
According to Holcim Foundation jurist Daniel Irurah, “a trans-disciplinary innovation emerged from this collaboration between communities and academic institutions. The project’s approach is not only empowering to communities; the experts also get to learn in the process”.
Designed for owners
Modular spaces allow for owner adjustments. First a basic geometry ground floor and first floor Eucalyptus frame is built. “Homeowners can then re- use the open platform and there is flexibility in how they use the ground floor,” says Donath.
With foundation and framework complete, workable design manipulations, including windows and interior walls, are left to the owners. They benefit from incremental construction by extending or finishing the unit to their preference and needs. This also puts owners in charge of spending. “The local community likes this open and flexible concept,” he says.
Use of local material
Recycled material, timber, plywood, concrete and metal – 90% of which is available locally – is used, not only lowering construction costs, but also facilitating environmental upgrading. “Old bricks, natural stone or clay can be used for the ground floor and wall infilling,” says Donath. For the cladding, virtually any available materials are applicable. “We’ve taken old rubber pieces, used plywood and metal sheets to showcase the re-use concept,” he says.
Eucalyptus timber is favoured for its high compressive strength and its partial resistance to water. While acknowledging any controversy, Donath says every community has its own Eucalyptus forest for construction purposes.
“As long as there is no other deforestation on a bigger scale, this timber will remain available locally.”
Pre-cast concrete is used for the foundations, concrete reinforced columns and smaller rain screen foundations. “The concrete is robust, locally available and modern,” he says.
Pre-cast adds to the industry’s alternatives for faster and more cost-effective construction. Kept to the minimum, metal is used for door and window frames, and a prefabricated metal staircase. “This project demonstrates a mechanism of adapting informal housing approaches to more durable and high-performance structures,” says Irurah.
It also creates opportunities for local economic growth, “allowing micro and small-scale business in prefabricated elements”, says Donath.
Quick and easy construction
Assembled by hand, a single basic unit can be constructed in nine days. The project team had to create ways for “the entire construction to be possible for unskilled people”, says Donath. “The connections have been reduced. All elements are numbered and marked with simple logos.”
Although the double volume unit satisfies densification principles, cranes are not available, hence the light timber frame. “The frame can be lifted by hand labour only. It is also for this reason that we’ve restricted concrete use to the ground level,” he says.
Improved urban environment
Integrating research, practice and the local community, this low-cost housing project could change the way in which Addis Ababa citizens live. But perhaps the greatest measure of achievement was the learning that took place on the ground.
“All collaborating parties ended up reflecting deeply on their roles, engaging with the process in an innovative and exploratory mind-set. Unlearning took place, opening up for new learning and innovation,” says Irurah.
Donath says the project is being taken forward. “It is on its way to be disseminated… starting with first stage training through Ethiopia’s Technical and Vocational Education and Training Strategy. Furthermore, the Ethiopian government is talking about 2000 units in the south of Addis Ababa,” he adds, although there is no confirmation yet.
“A better quality of housing and sense of community is anticipated, compared to prevailing informal or market-driven processes,” says Irurah.
The full feature appears in the December – January 2014/15 issue.