Panel technology is an invention which, when applied in construction, involves use of structural insulated and timber frame, lightweight steel frame panels and prefabricated concrete blocks.
Necessity is the mother of invention, so goes the saying. It thus follows that sustainable and affordable building technologies must be part and parcel of the planned provision of decent and affordable houses.
The escalating costs of construction, driven by high prices of building materials, expensive labour and extended durations of building, have made housing and home ownership unaffordable, especially for the middle and low-income citizens.
For a government keen on building thousands of units under its flagship Affordable Housing Programme, anchored in the Big Four Agenda, the quality of the houses is key to the success of this endeavour.
Statistics have shown that before the Government shifted gears, Kenya was building less than 50,000 housing units annually, against a demand of at least 200,000. It now seeks to provide affordable houses to thousands of Kenyans, with a target of 500,000 units by 2022. Technological advancement, as has been shown over time, enables mankind to find solutions to the challenges that come along.
What is panel technology?
Panel technology is an invention which, when applied in construction, involves use of structural insulated and timber frame panels, lightweight steel frame panels and prefabricated concrete blocks.
Materials used in panel technology include “expanded polystyrene” (EPS), which is the method most significantly deployed in the country’s building and construction sector.
“EPS technology is a construction system of prefabricated panels that are extremely light and can be easily transported from fabrication to construction sites,” says Engineering for Change, a consultancy, on its website, in a research paper it wrote jointly with UN-Habitat to guide builders on the materials to exploit in implementing the housing component of the Big Four Agenda.
Air bubbles trapped in the foam mean that EPS houses offer better control of climatic conditions, compared with houses made of concrete or wood. Since air is a poor conductor of heat, the building remains cool when it is hot outside and warm when external temperatures are low.
Touted as an affordable, ecologically friendly and efficient technology, the panel system is one of the innovations that the Government is betting on to help achieve the affordable housing component of its Big Four Agenda.
It involves building house walls by assembling already made pieces and later applying appropriate finishes.
A relatively new technology in Kenya, EPS panels in building and construction are boards made using expanded polystyrene blocks – often called styrofoam – which are cut to the desired dimensions.
The blocks are covered on either side with high tensile steel wire mesh, joined by steel wire connectors through the panel core, to form a three-dimensional composite of steel mesh and EPS core.
Since its recognition as a conventional insulating material in the 1950s, EPS has seen progress in other new implementations and is now used in a myriad building structures due to its sustainability, energy efficiency, durability and indoor environment quality.
The EPS panels are often used for partitioning in both residential and commercial buildings, in turn reducing concrete and steel reinforcement quantities and thereby saving on building costs.
The material is light-weight, a factor that contributes to minimised labour costs, formwork and construction time. These factors collectively contribute to reduced costs in construction.
EPS is a versatile material with different compressive strengths, enabling it to withstand load and backfill force during the construction. The material’s closed-cell structure also provides minimal water absorption and low vapour permeance and retention.
This environmentally friendly and aesthetically appealing material is also durable, has low maintenance requirements, is fast in application, and is economical when deployed for use in a construction. Further, the installation process of EPS does not need heavy construction equipment.
The material also ensures high levels of thermal and sound insulation, as well as sanitary and fire safety.
The Manual for Expanded Polystyrene (EPS) Core Panel System and its field application also indicates that EPS 3-D panels allow no additional cost to erect buildings in areas with moving soil, especially heaving, subsidence, frozen ground, and remote areas, while ensuring strength and durability since it does not absorb moisture and hence is resistant to decay.
The National Housing Corporation (NHC) indicates that EPS panel technology has been used in Kenya for at least 20 years now. The first project was at the Kenya Institute of Highways and Building Technology (KIHBT) offices in Industrial Area, Nairobi, in 1996. Other projects successfully built using this technology include Balozi Estate, a gated community in Muthaiga North, Nairobi, which was constructed in 2000, and the new expansion wing of the Silver Springs Hotel, Nairobi, which was put up in 2000.
The NHC has also managed to build multi-storey commercial buildings, including on Thika Road, opposite Thika Road Mall; Nakuru; luxury apartments for sale in Kanduyi area of Bungoma County; luxury apartments for sale opposite Nazarene University in Ongata Rongai, Nairobi; a gated community in Kisumu; school projects; offices; and go-downs in various parts of the country.
Affordable housing and building solutions provider Koto Housing Kenya is also employing the technology in its developments.
NHC says the materials come as single panels that can be used for building up to four storeys; double panels for structures of up to 20 storeys; and floor panels for making slabs for a maximum of 6 metre spans. Greater spans and heights can, however, be achieved when combined with a frame structure.
Green buildings have environmental, economic and social benefits, including improving water and air quality, and reducing waste; cutting costs, and expanding markets for green products and services. They also help enhance the health and comfort of occupants, and improve the general quality of their lives.
In 2013, NHC commissioned the NHC EPS factory in Mlolongo, Machakos County, to make this raw material as part of the Government’s efforts to provide affordable, decent housing for citizens. The factory has a capacity to produce 126,720 expanded polystyrene panels a year. General manager Andrew Saisi told a national newspaper that the panels delivered stronger structures compared with those made of stones and timber, while reducing the cost of construction by up to 30 percent.
EPS benefits
EPS is a cost-effective material that is light, strong, highly resistant to heat, moisture and sound, and provides good comfort conditions in any climate.
A standard two-bedroom house built using prefabricated materials from the technology is said to cost about Sh750,000. That is just about half the cost of using conventional stones or bricks.
The technology is mostly deployed in developing countries, especially in south-east Asia, Latin America, Africa and the Middle East.
This technology is often an ideal choice for green building designs as it offers noticeable environmental advantages that influence energy efficiency and provides a better-quality interior environment as well as enhanced stability.
With capable engineering, buildings can be made up to 20 storeys with this technology. The technology is advantageous in that it is generally light yet firm enough, making the panels easily manageable while assembling. This factor makes its installation quick and convenient.
Panel technology is also versatile and flexible, enough for a range of construction processes. This makes it the technology of choice for building large-scale houses for economically weaker sections (EWS) of the population, whereby units are built en masse and often targeted at residents whose incomes are below certain thresholds.
The lower costs for building stronger structures, and the simple and fast construction, make this feat achievable.
The material also presents buildings with high resistance to strains such as acute weather conditions and geological anomalies such as tremors. It is an inexpensive energy-saving technology that ensures comfortable heat conditions inside the buildings, a condition brought about by the presence of the polystyrene material, and also the low thermal conductivity effect that reduces energy consumption through heating, and hence the costs.
EPS also has fire-resistant properties due to the nature of the material used to make the panels, as well as sound-proofing quality, given the possibility to integrate acoustic insulation materials such as cocoa fibre, cork, and plasterboard, which insulate the walls acoustically.
The wide range of finishing is also a bonus for using panel technology in construction as smoothened plaster or conventional paint and any finishes deemed fitting may be used on the building. Deployment of panel technology in building also contributes to conservation of forests, given that wood is often a key raw material in most construction projects. However, with the EPS system, use of wood in construction is often minimal.
Its use also minimises degradation of the natural environment, which is often impacted by mining of stone and quarrying for building and construction stones. Because of its numerous advantages, panel technology provides an alternative to cheaper and less complicated forms of construction that only demand an opportunity to be tried out.
Case for EPS technology
Use of EPS panels as a substitute to traditional materials in erecting walls, staircases, floors and roofs, reduces construction periods as well as the direct and indirect building costs.
Air bubbles trapped in foam means EPS houses offer better control of climatic conditions compared with houses made of concrete or wood. Since air is a poor conductor of heat, the building remains cool when it is hot outside and warm when external temperatures are low.
Contributes to conservation of forests, given that wood, often the traditional component of most construction projects, will be employed minimally when this technology is fully expended.
The EPS panels are fire resistance due to the nature of the material used to make them.
In traditional houses, steel columns provide support at the corners. With EPS, the mesh of steel and concrete provide reinforcement around the whole building.
Properties of EPS panels
- Expanded Polystyrene, often referred to as EPS, is a kind of rigid, closed cell foam plastic. EPS properties have a low thermal conductivity, high compressive strength, is light weight, inert. It can be used as a building material or a design element, and can be molded into many shapes for a number of household uses as well.
- Expanded Polystyrene (EPS) is processed from its resin form. The resin contains a pentane gas which is safely released during the expansion process.
- Density: EPS density can be considered the main index in most of its properties. Compression strength, shear strength, tension strength, flexural strength, stiffness and other mechanical properties depend on the density. The cost of manufacturing an EPS is considered linearly proportional to its density. Non-mechanical properties like insulation coefficients are also density dependent.
- With the addition of steam, the EPS resin expands up to 40% of its original size. The expanded pellets are then transferred into a block molder.