The management of CLEZOL, a Rwandan construction company specialized in eco-friendly technologies, say Rwandans need to embrace new ways that reduce carbon emissions at an affordable cost.

The Kigali-based company champions Rammed Earth and CSEB (Compressed stabilised earth blocks) Technologies, construction techniques which use natural raw materials such as stabilized soil to build strong structures with a lifespan of slightly above 100 years.

CLEZOL, which was created by three Rwandan civil engineers, boasts of having worked as Main contractor at UMVA Muhazi, an eco-friendly hotel located on the shores of Lake Muhazi, as their first project.

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The engineers worked on the construction project of Rwanda Institute for Conservation Agriculture (RICA), before they came up with the idea to create their own company, which today claims some projects that have already been accomplished.

Having worked on RICA, UMVA and other completed projects, CLEZOL is as well currently working on different projects country wide.

"As the world is focusing on the target of achieving Net Zero carbon by 2050, we specialize in the projects and products that are eco-friendly and reduce as much carbon as possible,” CLEZOL’s Managing Director, Olivier Ngiruwonsanga, said.

"We want to raise awareness about Rammed Earth and CSEB Technologies, because they are not widely known. In Rwanda, people know about Fired bricks, cement blocks, and concrete. But with rammed earth, we build solid walls from soil stabilised by a stabilizer which may be Lime or Cement.”

Olivier noted that research and development is an integral part of everything CLEZOL does in pursuit of further improvement in the technology.

Although not many have embraced the Rammed Earth Technology, he said it has the potential of becoming the future of environmentally-friendly, affordable structures that need fewer maintenance works than the usual structures made of bricks and concrete.

How does Rammed Earth and CSEB Technologies work?

Rammed Earth Technology mechanically compresses soil with small amounts of a stabilizer, either cement or lime, CLEZOL’s Technical Director, Jean Claude Nziyumvira, explained.

There are two types of walls you can build using soil. There’s one called rammed earth wall, which is built with soil mixed with Low Percentage of cement and compacted in Layers into Panels formed till completion of a wall. Then there is also a wall built with bricks made by compressing soil, which are called compressed stabilised earth blocks (CSEBs), they came as normal bricks but made by soil and have a high compressed strength when it comes on its Strength Capacity, Due to their designed purpose RE and CSEB wall can be Load bearing walls on Multi-storied Buildings by Introducing some Vertical Reinforcement and this reduce dramatically the use of Concrete columns which can reduce Cost and save our Climate.

Apart from being an eco-friendly structure, rammed earth keeps the interior of the building comfortable either during hot or cold weather; there’s no need for air-conditioning, he noted.

The rammed earth structures are treated with sealants to make it both waterproof and dust-free.

Affordability and carbon emissions

With rammed earth and CSEB structures, you can save up between 20 and 30 per cent of the money spent on the regular cement and brick structures, Nziyumvira said.

"Rammed earth technology is very economical because it uses soil as the raw material that is readily available in the construction site. Instead of excavating the soil and disposing of it, you use it as the main component of your structure, and that means you will not have to spend money on trucks that dump the soil,” he noted.

Depending on use of most easily available raw material and limited transport costs, rammed earth structures reduce up to 70 per cent emissions of carbon dioxide, he said, adding that Rwandans have started embracing the new technology.

CLEZOL’s employment and community impact

The construction company today employs more than 300 workers including Engineers, Technicians and Casual labourers on the boundary wall Project of Bugesera Special Economic Zone, according to Ezra Nshimyumuremyi, CLEZOL’s Director of Operations.

"Besides, providing much needed employment to people, we also take part in community development activities such as Umuganda. In communities where we work, we also help vulnerable members within our means, such as renovation works of their houses,” Nshimyumuremyi said.

"We facilitate our workers in getting on-site trainings in construction so that within a certain period they can be promoted to a next skilled level i.e. Porters into masons, Steel fixers or Carpenters into Team Leaders, etc. As a Rwandan company, we highly consider ways we can help our workers to gain more skills in construction and we believe it will have a positive impact on the community,” he noted.

CLEZOL’s vision

CLEZOL aspires to become a key player in the Rwandan construction sector, and that will come as it gets reputed and trusted as a result of delivering on aesthetic, eco-friendly and affordable building structures, Ngiruwonsanga, the company’s managing director noted.

"In 15 years, for example, we will see our company grow with many engineers, as well as the number of people we employ generally. We want to see ourselves with more experience and working on and completing bigger projects. We want to see CLEZOL expand and impact more people in our society, and engage more women in the construction sector,” he said.