EPS (Expanded Polystyrene) technology is a construction technique that uses polystyrene foam panels as a lightweight and durable building material. EPS panels are made by expanding polystyrene beads with steam and molding them into large, flat panels. These panels can be cut to size and shape on site and used as a core material in a variety of construction applications.

EPS technology has revolutionized the construction industry by providing a lightweight, durable, and cost-effective building material.

The use of EPS technology has gained popularity due to its numerous benefits over traditional building materials. This article will explore the advantages of using EPS technology in construction, its various applications, and its impact on the environment.

Advantages of EPS Technology

One of the main advantages of EPS technology is its lightweight nature. EPS panels weigh significantly less than traditional building materials like concrete or brick, making them easier to transport and handle. This reduces the cost of transportation and labor required to install the panels. Most important, however, is what is in engineering terms referred to as the strength-to-weight ratio. EPS doesn’t weigh as much as other conventional building materials and thus when constructing a structure, say a highrise building, the self-weight of the building is lower. As such, when constructing using EPS, one can construct to higher heights as the self-weight of the structure is not as huge a concern as it would be when using conventional building materials. According to industry experts, EPS can be used in the construction of up to 20 stories, under the direction and guidance of a licensed structural engineer. In Kenya, this would ideally be a professional engineer registered with the Engineers Board of Kenya (EBK).

Another benefit of EPS technology is its high thermal insulation properties, owing to the significant quantity of entrapped air, which is a poor thermal conductor. EPS panels have a high R-value, which means they provide excellent insulation against heat and cold. This translates to lower heating and cooling costs for the building owner, which can result in significant savings over time. Indeed, the working principle of EPS highly correlates with that of Structural Insulated Panels (SIPs), which was our subject of discussion on this forum a few weeks ago. EPS panels can be used as a core material in SIPs, which are prefabricated building panels used for walls, roofs, and floors. SIPs are highly energy-efficient and provide excellent thermal insulation.

EPS panels are also easy to install, making them a popular choice for DIY enthusiasts. The panels can be cut to size and shape using basic tools, and they can be easily attached to a building’s frame using adhesive or mechanical fasteners. EPS panels have been observed to cut construction times by as much as 50%.

EPS panels are also highly durable and resistant to weather, moisture, and pests. However, EPS geofoam is highly susceptible to what is referred to as hydrocarbon attack, with the material rapidly disintegrating when it comes into contact with some hydrocarbons, say fuel. For this reason, care should be taken to prevent the exposure of the material to fuel spills, which might compromise the material’s strength and integrity.

The above advantages all culminate into making the technology affordable, with estimates indicating that the technology has the potential of saving approximately 30% of project costs.

Applications of EPS Technology

EPS technology has a wide range of applications in the construction industry. One of the most common applications is as insulation for walls, roofs, and floors. EPS panels provide excellent thermal insulation, reducing heat loss and improving energy efficiency. Furthermore, with wire mesh reinforcement, EPS can be used in the construction of load-bearing as well as free-standing (partitioning) walls.

EPS panels are also used as a core material in Structural Insulated Panels (SIPs), which are prefabricated building panels used for walls, roofs, and floors. SIPs are highly energy-efficient and provide excellent thermal insulation. They are also easy to install, which makes them a popular choice for modular buildings and prefabricated structures.

EPS technology is also used in civil engineering applications. EPS foam can be used as a lightweight fill material in road and railway embankments, bridge abutments, and retaining walls. The lightweight nature of EPS foam reduces the weight of the fill material, which can help to reduce the overall cost of the project. Because EPS geofoam is an engineered product it arrives on site already having undergone rigorous Q&A testing, unlike other fill materials that require time-consuming QA/QC testing.

Normally, conventional fill layers using gravel material require extensive tests to ensure that the fill layers meet the set standards and specifications. Field density tests are conducted at regular intervals on fill layers to determine the level of compaction. Furthermore, extensive tests have to be conducted on the fill material at source before its application in fill. Some of the tests conducted on gravel material include swell index, particle size distribution, atternberg limits – to determine the plasticity of the material, level of compaction that the material can achieve (maximum dry density at optimum moisture content), and perhaps the most important test being the California Bearing Ratio (CBR), which is an overall determinant of the material strength. These tests are time-consuming and labour-intensive. Furthermore, the installation of gravel fill layers (embankments) is highly curtailed by unfavourable weather conditions, such as when the area is experiencing heavy rainfall.

Apart from its use on embankments, EPS foams can also be used to construct approach fills for bridge abutments, owing to their high compressive resistance. EPS foams can support highway loading without overstressing the underlying soils. One challenge associated with the approaches to bridges is the differential settlement experienced at the abutment/approach fill interface, owing to the excessive settlement experienced at the fill layer, as compared to the bridge structure. The fact that EPS foams exert significantly lower stresses on the underlying layers means that this differential settlement is minimal and generally within tolerable limits. The use of EPS foams leads to lower construction costs and subsequent long-term maintenance costs. Further, when compared to traditional embankment fills, EPS geofoam exert reduced lateral forces on the abutment structures, retaining walls and foundations. The reduced forces exerted on these elements translate to savings in their design as they are no longer required to resist large horizontal static and dynamic forces. Grady Hillhouse has a very insightful video on the use of EPS Geofoam as a lightweight fill material, available here on his YouTube channel ‘Practical Engineering’.

Furthermore, EPS geofoam can be used over utility lines such as sewer and water pipes without the risk of the fills exerting immense loads that might burst the pipes. This also applies to existing culverts. EPS geofoam can be used to fill over culverts that were not designed to bear any additional conventional fills. When using conventional gravel fills, these services would normally require to be relocated away from the fill area.

EPS foams can also be used for fills under structures build over compressible soils to minimize settlement, under rail embankments, in landscaping, for slope stabilization and for stadium and theater seating. Just like EPS foams are used for road embankments, they can also be used under airport runways and taxiways.

EPS foam is also used as a flotation material in docks, buoys, and other water-based structures. Its lightweight nature makes it an ideal material for these applications, as it provides buoyancy without adding excessive weight.

EPS technology has been extensively used in developed countries. However, the technology is relatively new in Kenya and other developing nations. The good news is that the reception of this technology, especially in the construction of buildings, has been spectacular, with the National Housing Corporation (NHC) having established a Ksh. 700 million factory in Mavoko, Machakos County, to manufacture EPS panels. The factory was established in 2011 and began operations in 2012. It has the capacity to produce over 120,000 standard EPS panels per year. Additionally, many private developers have embraced the technology in the recent past and Kenyans in general are now more aware of the advantages of this new technology.

When used in the construction of residential or office blocks, the EPS panels are reinforced with galvanized wire mesh on either side. The minimum diameter of the reinforcing mesh should be 3mm. The panels are then plastered with a minimum of 35mm concrete plaster. The concrete plaster should be of class 20 and above. Note that these are minimum guidelines for simple ground-level structures. When doing more complex structures, always engage a professional structural engineer.

The use of EPS technology in other sectors such as in the Construction of roads and railways, however, is yet to take root in the country. The non-adoption of this technology can be attributed to the inaction by the relevant government bodies responsible for the development and adoption of the relevant standards and guidelines on the application of this technology. With the adoption or development of country-wide standards and specifications on the use of the technology in road, railway, and bridge construction, it is expected that the EPS technology will become widespread and be applied in cases whereby it proves to be more suitable than conventional construction methods.

Impact on the Environment

EPS technology has a positive impact on the environment, both during production and after use. EPS panels are made from a material that is 98% air, which means they require significantly less raw material than traditional building materials. This reduces the amount of energy and resources required to manufacture EPS panels.

Extraction of gravel material for conventional fills has always been an environmental concern, with the process significantly altering existing natural landscapes. Kevin Appolo, an environmental safeguards expert, notes that the extraction of gravel further leads to the loss of biodiversity, with the operation leading to the clearance of flora and the disruption of the fauna which depend on the habitat. The extraction of gravel material, he observes, further leads to increased levels of fugitive dust and noise pollution in the surrounding area, associated with the operation of heavy earth movers and trucks ferrying the material. Long-term exposure to polluted air has a negative impact on health and can lead to respiratory diseases. He further observes that excavation activities have the effect of weakening soil particles, exposing them to agents of erosion. Additionally, materials engineers are concerned over the sustainability of this practice, with alarm bells going off over the exhaustion of suitable gravel borrow material. The use of EPS geofoam as an alternative fill material can greatly address these concerns.

EPS panels are also recyclable and reusable. They can be recycled into new EPS foam products, reducing the amount of waste sent to landfills. EPS panels can also be reused in other construction projects, reducing the need for new materials. However, it is important to note that polystyrene, being an oil-based product, is not easily recyclable at an industrial scale. As such, unless the material is re-used into new EPS foam products, it ends up being atomized into small parts that are harmful to humans and animals in the long run.

EPS technology is also environmentally friendly during use. The high thermal insulation properties of EPS panels reduce the amount of energy required to heat and cool a building. This translates to lower greenhouse gas emissions and a reduced carbon footprint.

In conclusion, EPS technology has revolutionized the construction industry by providing a lightweight, durable, easy-to-install, and cost-effective building material. The use of EPS panels has numerous advantages over traditional building materials, including their lightweight nature, high thermal insulation properties, and ease of use.

EPS technology has a wide range of applications in the construction industry, including as insulation for walls, roofs, and floors, as a core material in SIPs, and in civil engineering applications.

PS: The header image shows the production of EPS Foam Block from Polystyrene Resin and Polystyrene Beads.