What is ICF? Understanding Insulated Concrete Forms

You have probably been searching the web for answers or maybe you are considering ICF for an upcoming project. So in this blog, I will aim to give you a basic understanding of ICF by answering some of these FAQs. 

It's important to note that times change, and so do our building methods. regulations as well as technological advances in building materials. When considering new methods and materials initially it can be frightening, especially when it's as important as building a safe, structurally sound building. 

When researching new building methods you ultimately want to know, whatever you choose, will result in a well-built structure that will stand the tests of time.

What does ICF mean?

ICF simply means Insulated Concrete Form. A “form” is a construction term used to describe something that retains concrete while it is being poured. Traditionally, “forms” are made from timber and are only temporary. The process of installing forms is sometimes referred to as “temporary works”. 

In the case of ICF the forms are made up of two panels of Expanded Polystyrene (EPS) that are joined together with a plastic web. Each block interlocks with one another forming a wall, once the desired shape is created, strapped and prop’ed appropriately the core is skillfully filled with concrete creating a solid structure. 

The EPS panels and the plastic web act as a proprietary formwork (forms) that are designed can withstand hydrostatic concrete pressure during the pours. In the case of ICF blocks they are not temporary. 

The EPS stays in place and acts as an insulating material for the finished building. ICF blocks are unique because there is insulation on both the internal and external leaf of the building which is extremely thermally efficient. Traditionally buildings normally have one layer of insulation, not two. 

Where did ICF Originate? (A short history of ICF) 

Rumor has it that pioneering Norwegian fisherman utilised disused polystyrene storage blocks (the ones used to transport freshly caught fish to markets) and filled them with concrete to build ICF buildings for themselves.  

Nevertheless the first recorded rendition of ICF was initially developed before WWII by two Swiss nationals, resulting in little interest at the time. But post WWII its popularity increased rapidly due to its quick, cost effective and solid construction, which was needed in post war Europe. 

However the first Polystyrene ICF block appeared in North America in the 1960’s. German born Werner Gregori, living in Canada, patented a design similar to what we know an ICF form looks like today. With EPS foam walls, a tongue-and-groove interlock system, EPS joined together with ties, and a waffle-grid core.

After initial hesitancy from many contractors, as you would expect, ICF building methods quickly spread across North America, to Europe and beyond. With growing popularity came an influx of ICF manufactures in the 80s and 90s. This resulted in the formation of the Insulating Concrete Form Association (ICFA) in 1992 (formed to promote the use of ICF in the UK). The formation of the ICFA marked the moment ICF construction seriously entered the mainstream construction sector.

So, whilst ICF building is far from as old as building with bricks, it has been used for over 60 years making it far from untested. In fact, its adoption has only grown as a result of its unique properties. 

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Why has ICF grown in popularity?

ICF construction has numerous benefits which explains why its growing in popularity within the UK construction industry. The growth of ICF Construction is attributed to the fact that its quick to build, durable, energy efficient, and affordable. 

People today are a lot more aware of their environmental impact and they are more open to the idea of implementing Modern Methods of Construction (MMC) to help reduce the impact we have on the environment. 

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ICF is one of many forms of MMC but its advantages make it one of the most popular. 

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Construction speed

The construction speed of ICF is one of its major benefits. Speed provides reassurance to all stakeholders involved, which, ultimately helps to reduce overall costs. Costs are controlled as a result of speed because the schedule of work is easier to commercially control. Quick builds means lower costs and your project is realised faster. So faster means increased popularity!

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Structural durability

The core of an ICF building is essentially a reinforced concrete (RC) structure, with an inner and outer layer of insulation. RC structures are extremely durable and are used in other construction sectors to protect against more extreme conditions such as terrorist activity, extreme weather events or just withstanding large forces in general. When installed and maintained properly, the life span of an ICF building is comparable to any other long lasting structure. 

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Energy efficiency

ICF buildings are very good at absorbing heat and retaining this heat making it very energy efficient. The way ICF buildings are constructed means that thermal bridging is drastically reduced. 

Thermal bridging is essentially a thermal weakness, in a building’s construction, that allows heat to escape through the path of least resistance. The ICF blocks material and the concrete core creates a unbroken barrier which makes it difficult for heat to find a path to escape, thus creating an energy efficient building.  

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Affordable

The affordability of ICF construction is becoming more and more apparent. If we take advantage of ICFs unique selling points, this MCC can be available to the masses. 

Now this is again subject to utilising efficiencies and implementing procedures as an ICF installer to help reduce the cost for the customer. Being able to afford to build and finance ICF buildings is increasing its popularity!

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If you're researching ICF as a construction method, this blog provides comprehensive information on its meaning, origins and its growth in popularity. From early experiments in Europe and gaining traction in North America in the 1960s, ICF was then formally adopted in Europe in the 80s & 90s. Ever since, ICF has rapidly grown in its popularity in the UK as a result of its many benefits, including construction speed, structural durability, energy efficiency, and affordability. 

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What is MMC? 

ICF like many other new techniques falls into a category of building called MMC, but what is MMC? MMC stands for Modern Methods of Construction, and this covers nearly any method of construction that is not “traditional” masonry brick/block work. 

The term MMC is used to describe not only new methods of off-site construction like timber frame, steel frame or modular buildings but also covers new products like ICF blocks that are built on-site but using new processes. 

It is very important to remember that ALL methods of construction, whether they be traditional or modern, must comply with the same regulations. Building Regulations for MMC products and systems must meet the same requirements for structural integrity, energy and thermal performance, airtightness, moisture control, fire spread, sound transmission. One of the key considerations when using a new-to-market MMC building system or product is the level of training given to the personnel who are installing that product. 

One of the biggest issues facing the construction industry today is mishandling and poor installation of products. As discussed on Radio 5 Live with an industry expert, fixing these “defects” is fast becoming one of the most costly unforeseen aspects of building new homes. You can read more and listen to that discussion here Is ICF Building Better?

We operate a stringent training and monitor programme within all our teams. If you’d like to learn more , please check out ICF Approved Installer Certification