Modular building techniques are revolutionising house-building in Africa. AfricanBrains editor Marc McIlhone, with a background in architecture, takes a look at an innovative company using the techniques to build sustainable housing for the poor.
Modular building is usually associated with either timber, steel or concrete construction, the two former being constructed off site and the latter using formwork on site.
The advantages are obvious with steel and timber construction as these modules can be constructed in factory controlled conditions, achieving a far higher specification of construction and finish. Highly skilled services such as electrics and plumbing can be installed off site so that lower skilled labour can be used to make the final connections when the building is in situ. One disadvantage of both timber and steel is their expense, both financially and environmentally, making them a less sustainable solution in terms of alleviating the housing crisis for the world’s poor.
Concrete modular construction, meanwhile, is cast on site – the material itself being less expensive than steel and timber. Although the construction is more labour intensive, it can be carried out by the local community, creating a sustainable skill base.
So it is clear that a combination of the two construction methods would be the ideal solution and this is where Moladi modular construction system, patented by Port Elizabeth inventor and Moladi founder Hennie Botes, comes into it’s own. The Moladi model has reached the finals of the $1-million global challenge to solve the crisis of affordable housing for the poor.
The competition was started by Hult international business school with the aim of finding global solutions to alleviating poverty, principally within the spheres of energy, education and housing.
Botes launched Moladi in 1986 using skills he had gained from being a tool and die maker. His product combines two interlocking inventions: a plastic formwork to shape the walls and a chemical additive to mix with the sand and cement required to fill them. The additive ensures that after the mixture has been poured into the formwork and set, the formwork can be removed and the brick-less walls will stand all the weather can throw at them.
Another advantage, Botes explains, is that the pre-planning and simplicity of design allows costs to be worked out precisely beforehand so bonds are easier to obtain. Cost is further reduced because a single formwork can be used again and again. In this way the Moladi system can build 50 houses in just 64 days.
Multiply the number of formworks and the output increases exponentially. With 100 moulds over the same 64 day time period, 5000 houses could be built, says Botes.
The simplicity of the technique allows for skills to be transferred relatively quickly and easily. Efforts are made to use local members of each community creating jobs and leaving a legacy of trained “housing entrepreneurs”.
Environmentally, Botes claims the Moladi construction system is more environmentally friendly than other methods because the additive mixed with the special stone-less cement creates “cork-like” walls, their thermal properties ensuring less heat loss in winter and less heat trapped in summer. A reduced need for artificially controlled temperatures means a reduced carbon footprint, Botes explains.
And these aren’t the only advantages, says Botes, “It overtakes the old technique of making bricks and then having to transport that heavy load to the site, plus the breakages incurred and waste of plaster with the plastering phase.
“With Model M, only the formwork must be transported to the site. Local sand is used to mix the cement and, because of the properties of the additive, the proportion of cement needed in the mix is much less than normal.”
Moladi’s aim is to improve the quality and reduce the cost of housing, while creating large-scale employment and training, which to me evokes the well-known proverb “Give a man a fish and he can eat for a day, teach a man to fish he can eat forever”.