EPS (Expanded Polystyrene) – An Amazing Building Construction Technology

Tired of the old construction method of slab, brickwork and/or masonry? Or you simply want to try something new? Then here I am to take you through an amazing building construction technology known as Expanded Polystyrene (EPS).

Expanded Polystyrene is a lightweight, rigid and cellular-like plastic foam made from pre-expanded polystyrene beads. It is commonly confused with Styrofoam. EPS was invented as an insulation material in 1951, but later produced as a construction material in 1965.

Understanding Expanded Polystyrene

EPS is made from styrene, a refinery product of crude oil. Styrene is in the form of beads which are impregnated, at high temperatures, with a foaming agent known as Pentane. This causes the pentane to evaporate within the beads and thereby expanding the beads 10-20 times their original size. The expanded beads are then stored for a period of 6-12 hours to allow them to reach equilibrium. The beads are later molded into blocks for use.

EPS blocks are tough foam panels with great insulation capacity, cushioning ability and impact resistance. They are therefore commonly used for packaging of goods or food. However in construction, where we will be focusing on, EPS is used as a construction material in form of panels to construct floors, walls and roofs. It is also used as an insulation material.

Expanded Polystyrene in Construction

EPS elements for construction consist of mostly single-paneled walls, double-paneled walls and floor panels. Single-paneled walls are used for buildings going up to 4 stories, while double-paneled walls can be used in buildings going up to 20 stories high. Floor panels are used as floor slabs. Single panels consist of an EPS foam sandwiched between electro-welded wire meshes on both sides. Double panels consist of two EPS foams sandwiched between the electro-welded wire meshes on both sides but with a vacuum between the foams. The hollow space also has wire meshes to provide the wall with structural functions when concrete is poured into the hollow space. The EPS foams can be of varying thicknesses ranging from 6mm to around 1300mm.

Now, let me take you through the EPS construction process.

EPS Construction Process

• Any building starts off with setting out. Once the structure is fully set out, shallow foundations are dug (depth depends on the structural requirements). The foundation is usually not deep because EPS panels are light, thus reducing pressure on the foundation.
• Floor panels are placed into the foundation. These floor panels have ‘channels’ where wire mesh reinforcement is placed.
• Necessary support is placed on the edges of the floor panels.
• Concrete is then placed and vibrated onto the floor panels. Curing of the floor slab is left to happen.
• The floor panels have steel dowels where the wall panels can be connected to. This allows for a strong connection between the floor panels and wall panels.
• The wall panels are fixed onto the dowels and meshes of the wall panels fixed together.
• Points of the wall panels that are usually load bearing, such as corners, are further reinforced using wire meshes. This creates virtual vertical elements (columns) and virtual horizontal elements (beams).
• The panels are then supported mostly by metal clamps, to prevent falling when concrete is poured into the panels.
• Concrete is placed and vibrated into the hollow panels and left to cure. Meshes in the hollow space act as reinforcement thus providing the wall with structural capacity.

Note: Concrete is placed into the hollow space of the double-paneled panels. Single-paneled panels do not have a hollow space to allow for concrete placement. This is the reason why double-paneled structures have a higher structural capacity compared to single-paneled structures.

• The supports are then removed after 2-6 days. The structure can now support the upper floor or roof.
• The wall panels have extending meshes at the top which allow for connection to the roof panels.
• Electrical and plumbing connections are placed on the panels through melting channels into the EPS foam. Since the foam is flammable, a blowtorch is used because it melts the foam rather than burning it.
• The walls are then plastered with grout or a stucco-like coating. The wire mesh on the outside on the panels provide support to the coating thus neglecting the need to provide an additional finishing coat.

Characteristics of Expanded Polystyrene

Expanded Polystyrene is a chemically formed element thus having a number of characteristics. These include;

1. It is lightweight.
2. Resistant to biological corrosion.
3. Recyclable.
4. Waterproof.
5. Insulation through reduction of effects caused by moisture and water vapor. Thermal insulation increases with increase in strength (density). Therefore, a denser panel is stronger and has better insulation properties.
6. Airtight thus providing soundproofing in buildings.
7. Highly flammable.

With all this information regarding EPS and its characteristics, let us now go through its advantages and disadvantages as a construction material. This will help us weigh the pros and cons of this technology and understand why it is an amazing construction technology.

Advantages of EPS

1. EPS is light in weight thus making it easier to handle during construction.
2. Being light, it reduces the cost of labor compared to that of common masonry technology.
3. Reduces overall cost of construction due to less concrete, formwork, reinforcement and labor required.
4. It has a high load bearing capacity despite it lightness in weight.
5. Has very good insulation properties. Keeps the building warm during the cold season and cool during the warmer season.
6. It is recyclable thus reducing wastage and damage to the environment.
7. Its airtightness makes the building soundproof.
8. Resistant to termites and rats.
9. Requires low maintenance effort.
10. Takes up less space compared to other construction technologies. This helps reduce storage space on site during construction.
11. Versatility in terms of its design flexibility.
12. Chasing of electrical and/or plumbing systems is much easier compared to chasing through masonry/concrete.

Disadvantages of EPS

1. Low fire resistance, meaning it is highly flammable. However, additives can be used to increase its fire resistance ability.
2. Needs some form of specialized labor to execute construction.
3. Material is fairly expensive.

Conclusion

From weighing the advantages and disadvantages of Expanded Polystyrene, we can clearly conclude that this building technology is an amazing technology full of benefits for the construction industry. So why not embrace it in your next construction project and reap its benefits?, either as a contractor or as a client.