The Insulating concrete form or insulated concrete form (ICF) of today is a system of formwork for reinforced concrete made with a rigid thermal insulation that stays in place as a permanent interior and exterior substrate for walls, floors, and roof. The forms are interlocking modular units that are dry-stacked (without mortar) like Lego blocks and filled with concrete. These units create a form for the structural walls or floors of a building.
However, they only became popular after the 1970s, when they came into the panel-like form we are now familiar with. Historically, the structures used to be timber, later followed by heavy-duty thick brick masonry walls (think old havelis that still exist throughout India). As space started becoming a constraint, these were replaced by thinner brick walls or stay-in-place structural forms that could be light-weight reusable plastic or flexible concrete formwork. However, these did not have the requisite thermal mass to provide sufficient insulation, which was much needed with the changing weather patterns.
Durisol, the first ICF, was developed in Belgium in 1937 by the Swiss nationals August Schnell and Alex Bosshard (Dutch patent registered in 1932.) The forms were made of cement-bonded wood fibre material. In 1938, Durisol AG, registered near Zurich, Switzerland, entered the international markets in the Netherlands, France, and Belgium after World War I – filling the void for a quick, cost effective and solid construction method using largely unskilled labour. The first patent for an insulated stay-in-place formwork for concrete was registered in the early 1940s using recycled waste wood and cement as the insulating material. The construction technique further developed in Europe following World War II as an inexpensive and durable way to rebuild damaged structures.
Subsequent International patents include The Canadian Patent in May, 1953 based on Swiss Patent Application, 1948 and subsequently Canadian Patent in 1949. By 1959, Durisol was promoted as cutting traditional construction costs by 20-30% and was produced in 13 countries. Therefore, it takes credit for having invented ICFs and being used in construction worldwide for over 80 years.
The first polystyrene ICF forms were developed in the late 1960s with the expiration of the original patent and the advent of modern foam plastics. The first patent for a foam concrete form filed in Canada in 1966, granted 2 years later.
It was named “Foam Form,” and each block measured 16 inches high by 48 inches long with a tongue-and-groove interlock, metal ties, and a waffle-grid core. The design remained unchanged for next 15 years.
One of the first ICF block construction projects was a home completed in 1969, in Ontario, Canada, where commercial construction with ICF blocks also began in that same year. BASF, the chemical company to invent EPS in Germany and Dow Chemical in the USA, took steps towards developing materials for ICF based constructions. Manufacturing units came up in Japan and Germany, USA & Canada by 1971. The adoption of ICF construction picked up after 1970s, (when panel style ICFs were developed), and has steadily increased since design standardisation was adopted two decades later.
As builders recognised the benefits of this alternative building material in the 1980s, many new North American ICF companies came up. These began ICF supplies to self-builders, developers and housing associations across the continent. Some set up manufacturing bases in Europe and began constructions in South America, Africa and Australia. Styrostone, a German based ICF company, went international in 1991, with several plants in EU to supply ICF in European markets. In the mid 1990s, ICF producers in America began training thousands of contractors for installing their building systems. The growth rate in sales of ICF forms increases from 50% to 100% each year until the first half of the 2000 decade at which levelled out to 20% - 30% each year.
Since the 2000s and till today, the “Green building” industry continues to grow even in the midst of major economic downturns in the West as ICF producers demonstrate how the attributes of their building systems, energy-conserving, easy & fast installation, small carbon footprint, durability, and extremely low construction waste - make them a perfect green building material. Many homes consuming Net Zero Energy or “Passive Houses” have been made in several countries.
ICF construction is now part of most building codes and accepted in most jurisdictions in the developed world. ICF block construction is commonly used for green building and sustainable building projects. ICF construction has become commonplace for both low rise commercial and high-performance residential construction as more stringent energy efficiency and natural disaster resistant building codes are adopted.
ICF in India (Since 2013):
Styrostone partnered with Reliable Insupacks (RIPL) in 2013 to make India's first ICF building, a farm house in Manesar, near New Delhi. 6 ICF projects were made between 2014-16 in North India alone. Reliable Building Solutions, initially conceived as a sister concern of RIPL, later independently introduced RELIABLE ICF, its building system, together with technical and logistical services, to support the construction of the greenest, highest performing, and most-cost-effective structures in the market today. It is among the most versatile and highest quality systems to construct new buildings in the future that will deliver performance levels in energy efficiency, natural disaster protection, fire resistance, and overall living comfort and health far superior to what can be achieved with frame and concrete block structures.
BMTPC’s PACS gave approval for RELIABLE’s construction material, ICF, in 2017, and there has been no looking back for us since then!