We offer an affordable solution that addresses both the problem of plastic waste and the housing shortage. Through extensive experimentation we’ve discovered a perfect mix of plastic waste, sand and gravel; and developed an energy efficient, modular and highly scalable technology for producing building materials. This is a way to recover resources from the waste and produce sustainable buildings with positive ecological and social impact.
The process starts with unsorted plastic waste. All types of plastic, including flexible, low quality and unrecyclable plastics, are first shredded into flakes smaller than 1cm. These flakes are mixed with sand and gravel into a uniform blend. This blend is then heated to melt the plastic, which becomes a binder thus removing the need for cement. The temperature never exceeds 250℃ and is carefully controlled to ensure that plastic doesn’t burn. The smoke from the heating vessel is directed through a wet scrubber and a system of bag filters to remove the pollutants before it is released into the environment. This hot mix is then molded into solid and hollow building blocks, roofing slabs, pillars, beams and pavement tiles.
We’ve built a 60m2 two-bedroom villa using these building blocks made from local materials, including 10 tonnes of plastic waste. Cement was only used in mortar and for plastering. The performance of this house demonstrated several advantages of using this new material instead of conventional cement blocks, especially in Sierra Leone climate. The roofing slabs and the blocks are good insulators and thus protect from the heat; it was cooler inside the house during a hot season compared to a house made from cement blocks. The blocks did not deform or melt when we exposed them to fire. This new material is also moisture resistant; the blocks don’t become damp after exposure to rain. The house has already performed well over the course of a particularly long and wet rainy season. The stress tests conducted by a local lab showed that the load bearing strength of these blocks is nearly twice that of conventional cement blocks.
Our agents will be spread across Freetown, concentrating at transfer stations and dumpsites, to buy plastic waste from formal and informal waste collectors. Since we are interested in all types of plastic that don’t have to be sorted, it will require much less effort from the informal sector to collect it. We will provide our agents with a mobile phone with a credit in mobile money to purchase a tonne of plastic waste, a scale and a manual baler. At our Buy Back Centers we will buy plastic waste not only from our agents, but from anyone, including households and companies willing to deliver their waste. Additionally, we will collect plastic waste directly from educational institutions and manufacturing companies. The price we will pay for plastic waste will be set with the aim to balance the need for affordable building materials and the need to improve the livelihoods of the waste collectors. Our building materials will be used in government construction projects, will be sold directly to construction companies and will be stocked by the outlets of building materials. We aim to sell building materials that are 25% cheaper than conventional cement blocks and have superior properties.
The impact of the Plastic 2 Build project will reach across many dimensions. Nearly 70,000 youths in Freetown are unemployed and 92.7% of people in Sierra Leone live on less than $5 a day; these people will directly benefit from creation of wealth and employment opportunities facilitated by the Plastic 2 Build project. We will provide skills training, with a special focus on women, and tricycles for our waste collectors, thus improving not only the income of people who work with us, but also their working conditions and future prospects. Affordable and resilient housing, schools, hospitals and public buildings will have a direct impact on the 60% of Freetown’s population that currently live in slums due to the lack of affordable housing. By supplying building blocks made from 100% local materials we will contribute to increasing the country’s GDP and reducing foreign exchange requirements.
Currently out of 90 tonnes of plastic waste generated in Freetown daily, 20 tonnes find their way to the legal dumpsites, Kingtom and Kissy, while 70 tonnes pollute our environment, block waterways and drains causing flooding, or are openly burnt. By diverting up to 25% of the plastic from the waste stream, we will contribute to extending lifespans of the dumpsites, unclogging drainage systems and improving air quality for everyone. Creating a market for all types of plastic waste, including the ones that cannot be recycled through conventional methods, will reduce plastic pollution and get us closer to the 40% recycling target set by the “Transform Freetown” initiative. The Plastic 2 Build project will result in savings for the local government, as less money will be required to collect plastic waste and to unclog drainage systems. Cleaner beaches will have a positive impact on the tourism industry. The most exciting part is that our solution can be adopted in other countries and benefit over 1 billion people who live in slums.