Moladi reduces high costs of conventional masonry through new alternative building technology
Africa is a rapidly urbanising continent, which according to the UN Habitat, is increasing at a rate of 230,000 people who are moving into cities across Africa each week. Currently, sub-Saharan Africa alone has an estimated housing deficit of 30 million units and every year, the backlog of houses across Africa’s 54 countries collectively increases by 4 million houses.
With the population of the African continent expected to reach a staggering 2 billion people by 2050, almost twice the population number estimated in 2010, it is a stark reality that every year, there will be more and more people needing homes, over and above the current demand.
Although the extensive and many complex difficulties, relating to the delivery of affordable housing in Africa is well documented, the ever-increasing demand for housing keeps mounting and continues to be a major concern. Projections by the United Nations would indicate that 53% of Africa’s inhabitants would comprise the urban population, of which 62% of city dwellers would reside in slums or informal settlements. What’s more troubling is that it appears that the incentive to move to the cities in Africa seems to be completely independent from economic growth and development and this is not expected to ease in the foreseeable future.
There is no doubt that the challenge facing the continent is a colossus, but the question is, whether conventional building methods are able to cope with the ever-increasing demand for quality homes.
Throughout history, man has become more sophisticated through technology; made improvements on existing standards and norms, which have ultimately been determined and developed according to the needs of the people. Perhaps the advances and progresses in communication and transportation during the past two centuries are the most evident of such improvement enjoyed by civilization. However, even though the need for housing has always been a fundamental requirement to sustain one’s health and welfare, the advances in this area have been somewhat meagre in comparison. The brick and mortar method of construction was recorded as early as 1458 B.C, which means that very little has changed in terms of building structures over a period of almost 3.5 millennia. With the demand and requirement currently facing us as Africans, we cannot expect to resolve the housing crisis in our age with a technique developed for the requirements of society 3468 years ago.
One such innovation is the award-winning Moladi building system, which looks at incorporating green technology and sustainability to provide the best solution to address the six key challenges that hinder the successful implementation of low-cost housing projects in Africa; namely, lack of sufficient funds, shortage of skilled labourers, lack of resources, work flow control, time constraints and wastage. The Moladi construction system was founded in South Africa during 1986, and has been in successful operation for the past 27 years. Moladi’s founder and designer, Hennie Botes, developed the innovative building technology as a means to alleviate many of the cumbersome and costly aspects associated with conventional construction methods without compromising on the quality or integrity of the structure. According to Botes, “Moladi looks at what has to be achieved now and builds on the knowledge and expertise of yesterday in order to develop sound methods to exceed the needs and expectations of ordinary people.”
The Moladi building system involves the use of a unique removable, reusable, recyclable and lightweight plastic formwork mould which is filled with an aerated SABS (South African Bureau of Standards) approved mortar to form the wall structure of a house in only one day. The process involves the assembly of a temporary plastic formwork mould the size of the designed house with all the electrical services plumbing and steel reinforcing located within the wall structure which is then filled with a specially formulated mortar mix to form all the walls of the house simultaneously.
The Moladi formwork components are fully interlocking and are assembled into easy to handle panels, weighing only 8 kilograms per square metre, which are configured into a full scale mould of the desired structure. The formwork panels are joined to form the external and internal walls cavities, producing an ultimate wall thickness of 150mm for external walls and 100mm for internal walls. All the steel reinforcing, window and door block-outs, conduits, pipes and other fittings are positioned within the wall cavity to be cast in-place when filled with the Moladi mortar mix.
All Moladi structures have steel reinforced internal and external walls. The reinforcing design is specified by an independent, certified Engineer; according to the requirements of the structure, which is dependent on soil conditions such as clay, expanding soils, collapsing soils, dolomite etc. The Engineer would also take into account if the structure would be subjected to earth tremors, quakes or hurricanes. As moladi structures are uniformly and monolithically cast, with the reinforcing placed in strategic positions, this makes the building more resistant to seismic movement.
The Moladi mortar that is used to fill the wall cavity is essentially concrete without stone. The mix design of the mortar is specifically determined by laboratory tests that are carried out on local sand or aggregate, to ensure that quality standards are adhered to. The density of the mortar will vary depending on the sieve grading of the sand used, but will range between 1600 to 1800 kg per cubic metre. The Moladi mortar mixture produces a fast curing aerated mortar which flows easily, is waterproof and possesses good thermal and sound insulating properties.
A compressive strength of between 15 and 30 MPa can be achieved in a 28-day period, depending on the cement: water ratio. Under normal conditions the mortar sets during the night (12 to 15 hours) and the formwork is removed the following morning. There is no need to vibrate the mortar in order to achieve a smooth finish.
At the start of each project, local building material tests are carried out to determine the unique mix ratios required to achieve the compressive strength requirement of the walls, which is specified by the appointed project Engineer.
After the wall cavities have been filled with the mortar, the mortar is left to set overnight and the formwork panels are removed the following morning to be re-erected on the next foundation. The wall has a smooth and flat finish that does not require any plastering, beam filling or chasing.
The result is a fast track cost effective and transferable construction technology that is amortized over 50 re-uses, which reduces the cost of construction and transportation significantly. This also facilitates the possibility for many in situ structures to be built in just one day. It is essentially the simplicity of its design and performance that contributes to the affordability of Moladi homes which are roughly 30% less than similar structures built using the traditional brick and mortar method.
Because housing is a primary sector of industry that can contribute towards the upliftment and empowerment of the unskilled and unemployed on a broad scale, Moladi wishes to meet the challenge of alleviating the hardships experienced by the millions of people in Africa who are fixed to the bottom third of the economic pyramid through the use, training and application of Moladi. Its contribution towards skills development in Africa could play a vital role in that the application of the Moladi technology is not dependant on skilled labour or artisans in its construction method and utilises local unskilled and unemployed labourers to build Moladi housing units. This allows for greater community participation and as more than 90% of the construction team on a Moladi housing site consists of unskilled labourers, who are trained locally by a Moladi foreman over a period of 2-3 weeks in order to transfer the required skills and knowledge to complete the entire construction process.
The training period is brief yet allows for a high standard of proficiency, as the Moladi construction method has been designed with the objective to allow for an unskilled team of people to follow Moladi’s optimized, repetitive and sequential processes that eliminates the probability of any errors occurring that are crucial to the outcome of the structural quality or integrity of a Moladi housing unit. Yet another developmental milestone is that women, who have traditionally been either reluctant or discouraged from working within the male-dominated sector, are encouraged to participate in the non-labour intensive Moladi building process. “The speed, affordability, quality, adaptability, ease of construction, use of sustainable local materials and the opportunity created to facilitate ‘sweat equity’ are key advantages that will greatly improve the efficiency with which the world addresses the problems relating to the world’s poor, homeless and unskilled communities.” says Botes
The Moladi technology components are manufactured and produced in Port Elizabeth, which is the 5th largest city in South Africa; a port city on the Indian Ocean coastline and situated halfway between Cape Town and Durban. They currently export their building system to over 17 countries worldwide, of which eight are members of SADC (South African Development Community). Moladi-Tanzania is one of their distribution points which are making great strides toward reducing the housing deficit. They are currently working on the Vicoba Moladi Housing Project, which involves the collaboration of Moladi-Tanzania and Vicoba Microfinance and Development Company to deliver a total of 9,000 housing units to low-income earners through community based projects.
Exporting Moladi to the African market is relatively easy as it can be transported to virtually any part of the world, including remote rural areas and informal settlements. An added advantage is that Moladi is not restricted through the use of heavy construction equipment and machinery in order to build with Moladi. Even the absence of electricity would not hinder the building process.
In recent years, there has been a steady increase in the development and availability of alternative building technologies in Africa, such as prefabricated building systems, from all over the world; many only hoping to capitalize from the growing demand for affordable housing in the African marketplace. Very few however have a track record which spans 28 years, or are socially acceptable to the African market. What most often seems to be overlooked is that, for most Africans, houses are also a reflection of their societal and are considered more than a simple shelter. Botes says that Moladi is able to accommodate any type of roof design or covering, any finishing material, any type of window or door, so there are no limitations or restrictions in terms of adapting Moladi to facilitate cultural design preferences. Notwithstanding the aesthetics and social acceptance of the structures, Moladi is accredited by numerous global building authorities and the building method conforms to international building codes of good practice. It has also undergone extensive testing by the South African Bureau of Standards (SABS) and the University of Panama to ensure that the resulting structure is durable and of the highest quality which has the key advantage of being able to withstand earthquakes and cyclones as it is a monolithic structure. Commonly, Moladi walls possess an average compressive strength of 15MPa or 15N/mm², which is far stronger than the average standard for cement blocks which vary from 3.6 N/mm² and 7N/mm² or common clay building bricks, which have a compressive strength of 5.2N/mm².
In its approach, Moladi brings to the field of construction all the benefits of a factory assembly line; quality assured work by unskilled labourers at a maximum rate of production with a high production output capacity. Yet, unlike many manufacturing operations, the benefits of the technology are transferred and spread to local communities through the purchasing, supply and utilisation of local indigenous materials in its on-site production operations. All materials used in the construction of Moladi homes, other than the formwork, are sourced and supplied from within the local community to stimulate the local economy.
The building materials required for the Moladi methodology are materials which are readily available, easily accessible and sourced locally. “By utilizing indigenous materials the benefits of the technology are spread to local communities” says Botes.
The selection and use of building materials relating to the Moladi construction process is considered a crucial aspect in determining the environmental sustainability of the Moladi technology. Although the calculation of embodied energy is a complex matter and differs from region to region, building materials used in the Moladi construction process have been carefully considered according to the initial and recurring embodied energy that is used or expended during the life cycle and operation of each material. Some additional, but notable, factors which affect the overall energy consumption of a structure – and which are often mismanaged within the affordable housing industry – is the requirement for nonessential transportation, wasteful packaging, plentiful waste of materials resulting from processing and construction methods, and also poor dumping and disposal methods.
Materials are rarely recycled or even reused and poor workmanship, the utilization of substandard materials and the use of materials and components which have a dissimilar and inconsistent durability, leaves the home owner with high a maintenance home which requires frequent repair and even large scale restoration. Lastly, passive design principles for the appropriate climate which helps to minimize the energy required to heat, cool, ventilate and light a building responsibly are largely ignored in favor of a cheaper initial cost outlay. These factors are taken into account to ensure that Moladi buildings provide environmental value by challenging members of the construction industry who are quick to ignore the long term use and quality of a building in favour of the short term saving enjoyed by the developer.
Of the materials used in Moladi homes, steel has the highest embodied energy rating of 44.66MJ/kg. However, steel is 100% recyclable and at the end of the buildings lifespan, can be removed from the building with relative ease for recycling. The steel reinforcing bars are essential for ensuring that Moladi homes are durable and structurally sound to ensure that the home owner has a safe and sturdy home which can withstand external forces. Plastic, the material used for the Moladi formwork, has the second highest energy rating of Moladi building materials at 43.03MJ/kg. The formwork however conserves energy due to the fact that it is durable and does not require maintenance. The formwork is re-used many times until it is eventually recycled into other durable household consumer products and construction components. Moladi utilizes a closed-loop policy with its plastic formwork so that none of the material goes to waste. The Moladi mortar mix, has the lowest initial embodied energy rating, which is 1.4 MJ/kg. The operational energy of the mortar is further reduced by eliminating excessive labour demands during the application of the mortar and ensuring that the resulting superstructure is constructed efficiently and in an optimized manner. The volume of Moladi mortar mix is accurately calculated to ensure that no excess material is wasted. The durability and longevity of the resulting structure requires minimal maintenance or repair work during the life of the building. Clay brick, which is 5.12 MJ/kg, polystyrene, which is 117 MJ/kg, cement plaster which is an average of 3.24 MJ/kg and Aluminium at 227 MJ/kg are other common building materials utilized in other types of construction methods which may be comparable to that of Moladi building materials.
All materials used in the construction of Moladi homes, other than the formwork, are sourced and supplied from within the local community. Specifying criteria is critical in that the fixtures, fittings and service systems installed in a Moladi structure have a durability term similar to that of the overall life expectancy of the building. Other than contributing to the local economy, this practice drastically reduces the need for additional and unnecessary transport and handling of goods and building materials. By reducing the number of operations required during the successful construction process means that there is a less chance of the occurrence of errors, waste and rework. This follows from the same logic that the fewer the number of operations, the higher the quality of the product, resulting in a predictive timeline and ultimately cost savings.
The Moladi method of construction has been designed to efficiently produce structures which have a long life, are durable and adaptable; homes which are considerate of the environmental impact as well as the needs of the home owner. The speed, affordability, quality, adaptability, ease of use, the use of sustainable local materials and the opportunity created to facilitate sweat equity are key advantages that would greatly improve the efficiency with which the world addresses the problems relating to the world’s poor, homeless and unskilled communities.
While a building technology such as Moladi will not resolve all the challenges faced by the African continent, it is clear that the use of a tried and tested and socially acceptable affordable housing system will improve service delivery and the lives of millions of poverty stricken families in Africa through its innovation.
Keywords – moladi, building technology, building technique, new technology, plastic formwork, African solution, rural development, new town development, affordable homes, low cost housing, fast track, system, alternative building technology, South African Bureau of Standards, Hennie Botes