Combining insitu, site-placed concrete and EPS (Expanded Polystyrene) as formwork is a method that has been available for many decades. EPS has been used as a type of ‘lost formwork’ in large projects where either repetitive or variable free-form shapes need to be cast in structural concrete. In these cases the EPS is either removed or dissolved with solvents in place to reveal the concrete shape formed by the EPS.
Since the 1970’s interest has grown in the use of EPS as permanent formwork for concrete, which led to the development of Insulating Concrete Formwork or ICF. ICF is typically a moulded stackable block EPS formwork for walls, which when assembled is filled with concrete to form the structural wall. The ICF remains in place to provide insulation to the structural wall and a convenient substrate for finishing materials.
ICF has undergone a long growth period to the present day with many manufacturers across the world developing and marketing their own individual products. Each has subtle variations but generally follow the same basic theme first developed in the 1960’s - 70’s. Most ICF products have certain advantages and disadvantages over each other, however many undergo constant product improvement to optimise on-site construction and technical performance.
A concrete structural shell that consists predominantly of sold concrete is described as High-Mass. It is well known that concrete is also the best contributor to Thermal-Mass which helps moderate and maintain comfortable internal temperatures for humans.
When concrete mass is encapsulated in permanently-in-place EPS insulating formwork, the EPS insulation moderates and very effectively maintains even concrete temperatures in hot or cold environments. The temperature of the EPS clad concrete in turn passively influences the average internal air temperatures more efficiently and effectively than any mechanical means.
A real potential of ICF and EPS formed concrete construction for housing is in innovative architectural design. Specific design strategies can exploit the flexibility and potential of EPS formed concrete to create modern architectural styles with ease. ICF based construction also produces buildings that deliver very high levels of performance for the user across the board, and a building of industrial quality robustness and strength.
EPS formwork and ICF technologies are the second part of the material and system focus of The SURI Project. The combination of the flexibility and performance of EPS products and the versatility, strength and performance of reinforced concrete form the basis of the Project’s core strategies.
Expanded Polystyrene, like concrete, is often criticised on environmental grounds, however this is often due to misinformation or lack of understanding of the product, how it is made and how effectively it performs.
Learn more about the characteristics and qualities of EPS and some very useful facts.