OMT’s Journey to Bring Timber Construction to East Africa
If Zanzibar had been full of architects with biobased construction expertise a decade ago, studio OMT architects—now a leading sustainability oriented architectural firm in East Africa --might never have begun designing timber buildings.
“It all started when a former client of mine came back to me and told me that he could not find an architect in Zanzibar willing and capable of designing him a building in timber,” recalls Leander Moons, founder of studio OMT architects. “I had no prior experience with timber. But I was interested in sustainability.”
What began as a one-off project ten years ago has now grown into a thriving architecture firm with 18 team members spread across three different offices. “So something went right,” says Moons. “But everything didn’t always go right from the start. We had a lot of challenges to overcome: the supply chain, acceptance of timber as a building material—and of course, the fact that building in Africa is quite different.”
Challenge #1: Designing single family timber homes from timber
OMT’s first timber design was a multi-family home for the Fumba Town development in Zanzibar.
The initial homes in the development had been single-story houses—some in timber and some in concrete (both sold at the same price). However, the single-story design had posed a challenge: it was difficult to keep homes affordable. The infrastructure required in a new development was expensive, so in a low-density model of single-story homes, it added significant cost to each home’s purchase price. “Homes become more affordable when we create density,” explains Moons.
In addition, developer CPS was interested in building the next round of houses all in timber, as the material had proven popular. The timber houses felt noticeably more comfortable inside, largely because they lacked the lingering smell of drying concrete—a significant factor in Zanzibar’s humid climate, where concrete takes a long time to cure.
To address both issues, OMT introduced the “Moyoni Homes,” a simple two-story timber design that included four dwellings under one roof. The approach paid off: eight years later, that model is the best-selling, most profitable house in Fumba Town, with 80 built and 80 more commissioned.
“We got it right from the start,” says Moons, “which I still find remarkable.” He goes on to explain that generally OMT value-engineers its initial designs substantially, to maximize all cost reduction opportunities. “But on this project we could never find anything to optimize,” he says, “So maybe it was the mindset of not knowing anything about the material that allowed us to figure it out right away.”
Challenge #2: Incorporating CLT
Next, OMT piloted cross-laminated timber (CLT) in the flooring system of the Moyoni Home, testing its potential.
“The client was so amazed by this material, the cross-laminated timber, that they asked us to do everything out of that,” said Moons. But designing the full house in CLT proved impractical. “Never again,” said Moons.
While CLT is very effective for specific applications, OMT has learnt it is best suited for large horizontal spans. “I would advise anyone who wants to build affordably not to use it vertically,” explains Moons.
By limiting CLT to horizontal applications—and otherwise utilizing timber-frame systems or more conventional materials, OMT has been able to reduce construction costs by about one-third across many of its projects, achieving a balance between performance and affordability.
Challenge #3: Meeting local demand
Moons notes that in much of Africa, residents aspire to the homes they see in Dubai, the Middle East, or Europe, which are built with concrete or masonry. “I often ask ‘Which country is the richest in the world?’” says Moons. “And, of course, they say ‘America.’ And then I ask them, ‘do you know what houses in America are made from?’ And they’re always surprised to learn that most single-family houses in America are stick-built. So I think in Africa we still have a bias in relation to how we see timber—as an inferior, simple building material.”
The success of OMT’s Moyoni Homes challenged this perception, establishing timber demand with middle-class homeowners. “Once we were able to show that people with money actually want timber houses, the local population got kind of interested. They started asking, ‘why are people with money buying these houses?’”
Building on this acceptance, OMT shifted its focus to affordable housing, —now less worried that doing so would fully establish timber as a low-quality material in buyers’ minds. It designed the first apartment building for the CheiChei project, also in Fumba Town—initially following guidance from the World Bank to focus on $25K two-bedroom apartments.
However, security concerns prevented OMT from placing two-bedroom apartments on the ground floor. So instead, it filled the ground floor with studios and duka workshops. (Duka is the Swahili term for shop). “To our surprise,” says Moons, “these were the best-selling offerings.”
The experience reshaped OMT’s approach. The firm now designs apartment buildings to maximize studios, 1-bedroom apartments, and duka workshops. “The two-bedrooms are still the most difficult to sell,” says Moons. Additionally, OMT has changed the design to integrate more conventional construction on the ground floor, to better accommodate residents’ needs, with timber construction used for the upper stories. “In the dukas,” explains Moons, “people want to hang things. They’re engaged in loud activities, some of which have high fire loads. So we changed the design to accommodate how people are actually using the buildings.”
Challenge #4: Working with local building codes
In most situations, explains Moons, architects rely on building codes to guide designs. But in many parts of Africa, building codes don’t address timber construction. So building with wood requires a more collaborative approach with local officials to ensure timber buildings meet safety standards.
“For instance, in Zanzibar, we worked with government officials and consultants to blend the British and Swiss code to develop fire safety requirements for the portico structure,” explains Moons. The innovative approach ensured safe egress from the apartments in case of fire.
In other cases, OMT integrates conventional structural elements to ease officials’ concerns. “For multi-story apartment buildings, we keep the core in concrete,” Moons notes. Technically, it’s not necessary, but it provides reassurance for authorities when permitting the structure.”
Challenge #5: Using local materials
“Part of our story is that we’ve only been able to build out of timber in East Africa by importing quite a lot of the material,” says Moons. “Critics point out that using imported wood isn’t sustainable.’ And they’re right in a way. But if we don’t build with timber, we don’t create demand that will drive the industry to actually grow. So that is the real question: how much unsustainable importing must we do to create the demand needed to drive the growth we need in the manufacturing sector?”
Moons explains that the East Africa timber industry isn’t yet mature enough to support construction needs. “Interestingly, there are a lot of plantations in Tanzania,” he notes. But without enough sawmills to process the trees into graded construction materials, felled trees largely end up in paper mills.
Whenever possible, OMT has made great strides to incorporate local materials. OMT architect Wekesa George recalls a value engineering initiative that led OMT to combine CLT with locally sawn timber. To make the project work, OMT successfully convinced a local sawmill to begin grading local lumber for construction.
Unfortunately, a neighboring sawmill attempted to imitate the process by painting its lumber to mimic grading. “Still, it marked progress in primary processing,” George notes. “And it became quite normal to have wood of a good quality.”
Moons cautions that developing local timber capacity is a gradual process. “Everyone talks about CLT—about the Ferrari of the timber products,” he says. “But in East Africa, we first need to get to kiln drying instead of air drying. We need grading. We need consistent sizing of timber elements. We need to create awareness around why these things matter. So there’s a lot of work to develop local timber products and move away from imports.”
Adds George, “Our goal is local manufacturing of CLT, significant value add to local forestry, and skill building around mass timber construction. But the journey starts with us trying to incorporate local timber in very simple ways and supplementing with imported timber. Maybe eventually, we can rely largely on local timber and import only a few elements.”
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