Are Insulating Concrete Forms Underused in Australia? 8

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Thursday, October 29th, 2015
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Insulated Concrete Forms
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Insulating concrete forms (ICFs), also known as insulated concrete forms, are used in many developed countries to create highly durable and efficient structures. Developed in Europe after World War II, the forms are typically rigid foam blocks made of polystyrene or polyurethane. Sometimes they’re made from polystyrene beads bonded with cement, cement-bonded wood fibre, or cellular concrete.

The forms interlock to create a stable wall system and are filled with concrete. The forms can be made as sheets to which plastic or metal fasteners attach to create two walls with a central void, or they can be formed as complete blocks with central voids. The forms remain in place to provide insulation value and an air barrier.

As with any other building method, ICFs have their pros and cons. Benefits of the system, proponents claim, far outweigh the drawbacks. Concrete is certainly durable, with the ability to withstand rot, pests, fire, and extreme weather such as cyclones, tornadoes and earthquakes. A home in Mississippi that employed ICFs is reputed to be the only home in the area to withstand Hurricane Katrina in 2005.

Insulated Concrete FormsHomeowner and builder, Scott Sundberg, a structural engineer, designed and built the structure to withstand the area’s hurricanes, and the structure held up remarkably well to the storm’s seven-metre storm surge and winds of 200 kilometres per hour, while neighbouring homes were swept away. As for cost, Sundberg noted that “using concrete adds about 10 to 15 per cent above the cost of conventional construction.”

Critics point to the carbon footprint of concrete, as cement manufacturing is estimated to contribute about five per cent of global CO2 emissions. Cost may also be higher than other building methods, though that can be hard to judge, depending on the methods chosen for other systems in the house. In addition, in areas without extreme weather events, there may be no reason to exceed the minimum code standards to build a stronger structure.

So far, ICFs are not much used in Australia, but the adoption of a particular building system may actually have little to do with its cost/benefit ratio. Dr. Paul Downton, architect and writer, author of Ecopolis: Architecture and Cities for a Changing Climate, noted that “construction systems that are new to the market have to contend with the inertia of established systems.”

Brick veneer building techniques, for example, may be the favoured method in Australia because of history, business, or economic considerations, not because they’re the “best” methods.

“The domestic construction industry has developed to favour brick veneer building techniques and the entire supply chain reflects that,” wrote Downton. “The entire system favours a particular kind of construction that has, in turn, refined its costings and the inter-relationships of component suppliers over time.”

Building codes can also play an outsized role in the ubiquity of different building systems.

“There would be a level playing field for double-glazing, for instance, in Australia if the National Building Code required insulated glazing units like the codes do in many other countries, such as the UK,” Downton said.

One of the most common dings against concrete buildings is the carbon footprint of the structures. According to Downton, ICF structures may be acceptable if the structures save energy compared to conventional buildings.

“If it can be demonstrated that the ‘carbon investment’ required to build with ICF pays off in energy-saving over the anticipated life of the building it may yet become a construction system of choice for the increasingly climatically challenged environment that global warming is promising to deliver,” he noted.

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8
  1. John

    Hmm … do I want a wood frame house that burns during wildfires, blows over in storms, rots, etc. or do I want a concrete house that doesn't. This is a no-brainer.

    Imagine what would've happened if the recent Cat5 hurricane that hit Mexico had hit southern California instead. Mexico builds with concrete, and there were very few reports of damage. We build mainly with wood, and the damage would have been in the billions!

    The 5-10% add on for a disaster resistant house is well worth it. The article mentioned 10-15% but that is a bit high from my experience. The article didn't mention lower energy bills and lower insurance premiums which offset the construction cost.

  2. John

    Don't believe the CO2 nonsense mentioned in the article. While it is true that concrete has a higher carbon footprint than wood … a concrete house uses less heating and cooling energy than a woodframe house during its lifetime … and studies show that the CO2 associated with heating and cooling is significantly higher than the CO2 associated with construction.

    One study in the USA showed that within 10 years after construction, a woodframe house had a higher total CO2 footprint than an ICF house.

  3. Eric

    we are looking to build a house with SIPs and we spent months looking for builder know the system and can compete with price. NOTHING….. The same case as ICF. We looked at it but the cost of build is higher which make no sense becuase it is a much shorter time frame to build the house. Now we may have to force bakc to lightweight material only and pack extra insulation.

    • Jean SmilingCoyote

      I urge you to keep looking to get it built with ICFs.

  4. Malcom Roberts

    One of the ironic aspects about concrete is that despite its high carbon footprint at the beginning of the cement manufacturing process, global warming in actual fact may drive demand for buildings of greater resilience – of which concrete is one.

    I suspect that with any type of concrete in general, popularity may rise or increase in cyclone or natural disaster prone regions but decline in less natural disaster prone areas.

  5. David Kuhnert

    As a member of the ICFAA I find this article more of a challenge to the wider Building construction industry in Australia for dragging it feet when it comes to better way to build . We can`t keep going down this dead end road the way we are in the building industry , we must start looking at multi generational , energy efficient , multi functional , Sustainable , cyclone & bullet proof , ICF ticks all the boxes . It is Architect like Paul Downton AUST , Martin Chant NZ , Patricia Vandenbruel Syd who challenge the way we build & how we make them user friendly & long term ecomonical . As John Said It`s a no brainer Regards David Kuhnert .

    • Jean SmilingCoyote

      You could actually generalize this to "reinforced concrete with insulation." There are 2 other types of this construction I like.

  6. Jean SmilingCoyote

    I like ICFs especially for their tornado-resistance here in the USA. The insulation reduced heating & cooling costs a lot. The reinforced concrete makes a building highly resistant to crashed by wayward cars. It's happened. Brick veneer over wood frame is fine if you like cars crashing through the walls. I'd recommend ICFs in Australia mostly because of thermal insulation and fire-resistance, if you use fire-resistant exterior coverings in walls and roof. I've read people are doing research to reduce the carbon footprint of concrete.
    I wish you wouldn't mention the term "insulated concrete forms" as an alternate, because it's grammatically incorrect. The forms provide the insulation; they are not insulated by anything.