One of the ways with which a developer interested in building in Kenya is able to reduce construction costs is through the application of prefabricated construction systems. Prefabricated systems are construction systems in which the construction elements are formulated in advance prior to being assembled on site.
Prefabricated construction basically entails construction of building elements using modular panels that can be cast or formed away from a construction site. Thereafter once this has been done, it is simple for these construction elements to be moved to a construction site and assembled together using appropriate building technology on site.
Types of Prefabricated Construction for building in Kenya
There are systems of prefabrication that are becoming commonplace in the construction market, though their popularity has been slow in coming. Most Kenyans favor the conventional methods of construction because they are familiar with them. In addition, there are social factors at play with regard to matters of security concerns as well as simple social bias. Many would rather build a stone masonry house than commission a prefabricated unit due to perceived social bias and comparisons. With these factors in play, the growth of the Prefabrication sector has been slow in in building in Kenya.
Types of prefabrication available for building in Kenya
There are several types of prefabricated units that are available, including prefabricated systems made of steel, timber and concrete. The method of formulating these panels differs according to the materials that shall be used to construct them. However, they all depend on creation of modular panels that are repetitive and can be mass-produced, then can be reassembled once they have been transported to the building site.
Steel Structural Insulated Panels are a potential method of construction of building in Kenya using prefabricated steel panels. The shortage of steel in the country means that these panels are not manufactured locally, but are imported from the far East. They are constructed using thick metal plates with a layer of polyurethane in between them for insulation purposes. The construction of these prefabricated units means that they are light in weight and can be easily transported from a factory and assembled on site.
By virtue of their factory manufacture, there is very little wastage in their construction and one can attain a very high level of accuracy in its assembling.
Timber prefabricated housing is another key material that can be utilized for creation of housing and building in Kenya. These units are constructed with timber joinery that has been prepared at a factory and this is then assembled together on a site. The timber sections are also clad with simple boards that can give a smooth interior finish if one does not want the timber look on the inside. This internal board can be painted and finished as preferred. The prefabricated unit however may be given a concrete base on which to stand on which has been waterproofed and has received appropriate anti-pest treatment.
Concrete and cement based prefabricated systems are possible to create using prefabrication. These factory made panels are created using molds cast in place and connected together on site. Various methods of reinforcing of these prefabricated concrete panels are available, including use of reinforced steel sections, wire meshes and steel bars. Their factory formulation allows for the quick formulation of panels that can be mass produced.
There are several type plans that are available for creation of buildings, and all of these are based on a modular system of construction. The finished product of the prefabricated systems is usually through a cladding that can be intrinsically applied to the prefabricated panel or can be fixed once the panels are on site.
Economic factors can also create challenges for use of prefabricated units when building in Kenya
Prefabrication however is an expensive process for one unit, and only economies of scale makes its use worthwhile when building in Kenya. The process of prefabrication, whether being done locally or abroad, calls for establishment of a factory to undertake the manufacture of the modular panels that will ultimately be assembled on site. The creation of the panels itself calls for a computerized system of creation of the various modules in an entire precision based process. The end result is panels of an exact nature that are easily bolted together on site.
The modular panel systems also offer certain rigidity in their building designs, and there are certain building geometries that are not encouraged in the use of these modular systems. This can be a limiting factor for Kenyan architects and clients who may be interested in more organic architectural forms. This is an area which prefabricators need to explore to enhance their available typologies for building in Kenya.
Prefabricated units are able to reduce the cost of building in Kenya through their characteristic of an extremely short time for erection of built structures, once the panels have been manufactured. While a conventional building may take months to complete, a prefabricated building will take only days to assemble on a building site. The key ingredient is that the technology is available in the country.
That being said, building professionals are well advised to consider the use of prefabricated panel construction as a way of reducing costs of building in Kenya.