The Expanded Polystyrene System (EPS) is one of the alternative building technologies that has created quite a stir in the Kenyan market. The EPS panel can be used in place of traditional masonry/brick and reinforced concrete elements like walls, slabs, stairwells and roofs. According to research by the National Housing Corporation (NHC), EPS panels can not only reduce the construction period of similarly sized houses by up to 50%, but they can also reduce direct and indirect construction costs by 30%.
This is music to the ears of any local domestic or commercial builder looking for less expensive, alternative building methods. Kenya and East Africa have long lagged in adopting alternative building technologies. Masonry is structurally sound, is widely taught in technical institutions, and its costs can be reasonably predicted.
Masonry is structurally sound, is widely taught in technical schools, and its costs can be reasonably predicted.
EPS panels, on the other hand, were only introduced into the market about a decade ago. Aside from NHC, a government agency promoting the adoption and use of this product, there aren’t many tangible projects demonstrating the use of this technology, explaining the slow uptake.
Is panel construction for you? What are its advantages and limitations when compared to traditional brick and mortar?
Let’s dive into the 5 considerations comparing these two building methods.
EPS Panels Have Great Structural Integrity
EPS is made of a polymeric styrene material traditionally “sandwiched” between two layers of steel mesh of 1.5mm diameter. The meshes on either side are spot welded together with connectors passing through the core of the panel. Once set in place, shotcrete is applied to both sides of the panel under pressure and regular finishing can be done once the concrete mortar sets.
From a structural perspective, the EPS panel has higher structural integrity than a masonry/brick-and-mortar combination. This is because the EPS-shotcrete material behaves monolithically and has no joints, compared to the same area of masonry wall which has numerous joints and thus points of weakness. Additionally, due to the monolithic nature of the finished panel, the EPS can take on high loads at a lower weight compared to the masonry/brick alternative.
The polystyrene panels are also coated with non-asbestos fire-retardants which keeps them fireproof. Due to fewer joints per wall area, less water or moisture can penetrate the core of the wall.
2. Less Weight of The EPS Panel Means Lower Foundation Costs
Foundations take up a substantial chunk of construction costs for traditional masonry buildings, due to the weight of the walls and columns. With reduced structural weight for the EPS alternative, the foundations can be shallower meaning less structural costs.
3. Construction Moves Much Quicker With EPS Panels
A typical EPS panel measures 1.2m by 2.7m, although they can come in various other sizes. For the same area of masonry or brick walling, not only does a deeper foundation need to be dug; heavier material needs to be hauled to site, and the construction process of mixing mortar and brick laying takes longer.
With EPS, the panels are first placed in their proper position and simply tied at the intersecting edges using tie wire. This process is easy and can take just a few minutes with two workmen. The shotcrete process also moves faster as a concrete spray under pressure is preferred to hand shoveling.
4. Hybrid Construction Is Supported With EPS Technology
You can build a hybrid stone–EPS structure without affecting the structural integrity of your construction. This is often a point of worry or contention amongst local builders especially those who haven’t used the EPS technology before.
With a traditional reinforced concrete shell (i.e. beams and columns), panel walling can be introduced instead of masonry or brick. Since EPS panels are fabricated to standard floor-to-ceiling heights, the EPS panel can be well grouted at the point of contact with the lintels and thus ensuring no gaps in the walls.
5. You Don’t Need Specialized Staff For EPS Installation
Just like traditional masonry/brick construction, EPS panels can be installed with the usual caliber of labor. Only light training is required for the fundis who install the panels. This training may include how to set and align the panels, how to tie panels side-by-side with binding wire, how to perform shotcreting, and most importantly, how to install floor and slab panels for multistorey buildings. None of this is specialized knowledge.
Are There Backsides To Using EPS Over Masonry/Brick?
Not enough studies have been performed locally to determine the suitability of EPS panels for multistorey construction above 10 floors, although the NHC has built a hybrid 5-storied EPS housing complex. Currently, the EPS panels are slightly higher priced in Kenya than in countries such as Italy and Argentina where the technology has been widely adopted. Thus, the cost comparisons and advantages are yet to be fully studied in the local Kenyan context.
Finally, as with any new or alternative technology, mass adoption by local builders and developers is yet to be adequately realized due to a lack of awareness and apathy generated by misinformation.
