Insulating Concrete Forms

Peter Nynkowski is building an environmentally friendly cottage in Haliburton, Ont. with the help of insulating concrete forms (ICF). "The main structure has been built, but the hydro isn't hooked up yet," he says. "Even with temperatures at .15 degrees outside and no indoor heating, it's quite comfortable."

ICFs come in various shapes and sizes, but the principle is the same. Foam is sandwiched together into large interlocking blocks that provide a cavity )typically 6-10 inches) for filling with reinforced steel and poured concrete. The walls are typically vibrated to ensure there are no air pockets formed in the wet cement.


Benefits of Insulating Concrete Forms (ICF)

A cottage built with ICF offers superior insulation from outside temperatures and noise, and provides a solid construction.

  • It is more energy efficient (32-44 per cent savings).
  • Virstually dust and pollen free.
  • Although the walls allow little sound penetration, you must factor in the noise coming through the windows, door and roof.
  • The strength of the construction offers the ability to install larger windows and longer floor spans.
  • Doesn't emit CFCs, HCFCs or formaldehydes.
  • Will not rot or decay.
  • More resistant to fires (two to four hour fire rating).
  • Resistant to termites and pests. There is nothing for these pests to eat, and they can't burrow in the concrete.
  • Concrete has the heat-absorbing property called thermal mass, which evens out the extremes in temperature.
  • The continuous layer of insulation reduces drafts.

Artificial Ventilation System Required

Older homes are naturally leaky, which allows the stale air out and fresh air in, actually providing a natural ventilation system. And in the past when it felt chilly and drafty inside, we would simply turn up the heat, never thinking twice about our heating costs or the environment. 

Up to 40 percent of your heating costs go to drafts, which are mostly coming from the walls. But those heat-robbing drafts while hazardous to our wallets and the environment, provide fresh air to breathe.

Moisture coming from washing, cooking, showers, and breathing provide breeding grounds for mould, mildew, fungi, dust mites and bacteria. Appliances, gas ranges, water heaters, invented space heaters, leaky chimneys and wood-burning appliances all add to the problem of polluted indoor air quality. Because of the air-tightness of an ICF system, it is absolutely imperative that the cottage owner install a proper ventilation system (HRV or air exchanger) to remove the household air and bring in and filter fresh air. Too much moisture in the cottage and not enough circulation will lead to mould.

How to choose a geo-exchange system 

When choosing the system from one of the 24 ICF manufacturers in Canada you will need to consider certain factors:

  • Is the system available in your municipality?
  • Does the manufacturer provide adequate training? Builders already have the skills required to easily learn the ICF system.
  • What is the level of customer support?
  • Are you able to obtain a building permit for this system? Some municipalities are unfamiliar with ICF and may require some education.
  • Ask if the forms are manufactured from 100 percent recycled material, if all the waste produced is 100 percent recyclable, and if the material is local to decrease transport emissions.
  • The energy efficiency and the cost of ICF depend on the type and thickness of the material used.
  • Some manufacturers' products are easier to use than others, and some have better training, which does affect labour costs.
  • Once the structure is built, adding or moving doors, windows or utilities is difficult because you will need to cut through concrete; make sure you like the design.
  • Typically, an ICF system costs 5-10 percent more (depending on material used and labour) to build than a traditional wood-frame construction.

Performance R-Value

Nynkowski hired a contractor, Frank Hardin, who states he was particularly impressed with the real R-value or performance value of the ICF system. 

The R-value is the measure of resistance to heat flow. It typically refers to the insulation material that is used, and not to the wall or ceiling assembly. The real R-value or the performance R-value includes the woo framing and sheathing (which typically have a low R-value).

Hardin explained that in a wood-frame construction, walls consist of 2 X 6 wood studs making up 15 percent of the walls, which have a very low R-value of 5. An ICF wall doesn't use studs because the concrete construction is continuous, making the performance R-value of the building much higher, reducing energy required and making the building much more comfortable to live in because there are no drafts.

Is ICF Green?

Green is the buzzword in the construction industry and often building manufacturers will tie a green helium balloon to their product in order to make you and them feel good, and of course, sell more products.

The building practices of the past are outdated and unsatisfactory for today's environmental standards. As science and public awareness develops, changes are being made. ICF homes, in comparison to traditional stick-frame homes, reduce energy use by 32-44 percent, save our natural resources, reduce greenhouse gas emissions, produce less construction waste, and the structure will stand the test of time.

Environmental life cycle assessment

It is impossible to have a decent discussion about green building practices without at least partially understanding the environmental life cycle assessment (LCA). The LCA looks at all aspects of a building product's life cycle from the moment the needed raw materials are extracted from the earth, to transforming and processing these raw materials into a useful product, the fuel used for energy of the product, the repair of the product, the impact of the product on our natural resources, using the product, and the possibilities of recycling or disposing of the product back to nature.

Concrete draws upon the earth's most common and abundant minerals for its raw materials. The amount of land used to extract the materials to make concrete is only a fraction of that used to cut down our forests for lumber.

Concrete uses recycled materials. Sources of aggregate are diverse and plentiful including sand, gravel, crushed stone, consumer and industrial waste products, and crushed concrete from demolition. Also, it has absolutely no degradation of strength or performance. Concrete is naturally waterproof, storm-proof and fire-resistant. Its durability over decades goes a long way toward waste reduction.

However, ICFs share the environmental disadvantage of the concrete construction and the high levels of energy embodied in the cement (and the pollution associated with that.)

Typically the insulating sections of ICF are made from expanded polystyrene (EPS) or extruded polystyrene (XPS). Enormous amounts of energy are expended on the production and transportation of these products to get them to a store near you. Some manufacturers present other materials, which may be greener such as mixtures of cement and wood, or recycled polystyrene and cement.

Visit the Insulating Concrete Forms Association website at www.forms.org for more information.


LEED

The green building rating system called Leadership in Energy and Environmental Design (LEED) is a voluntary, consensus-based national standard for developing high-performance, sustainable buildings. It provides a complete framework for assessing building performance and sustainability goals. Points are given for structures (not companies or products) that meet certain criteria such as sustainable site development, water savings, energy efficiency, material selection, recyclable content, construction waste management, regional materials, environmentally responsible forest management, low emitting materials, thermal comfort, better daylight and views, optimized energy performance, minimization of impact of building on microclimate and human and wildlife habitat, and indoor environmental air quality.

There are four levels of LEED certification and they run from 26 to 69 points. ICFs generally earn between 19 and 29 LEED certification points.

Although a formal ICF training program is now available and being adopted by trade organizations, builders have the basic skill set to learn the system via training provided by the manufacturer.

A perfect green stamp is hard to earn. Because ICF uses mostly recyclable products, is capable of dramatically reducing energy consumption now and for decades to come, is sustainable and recyclable at the end of its life, I think it earns an olive-coloured stamp. Besides that, it's a very comfortable and quiet cottage to live in. 

Go to www.insulatingconcreteforms.ca for a list of Cement Associations offices across Canada. 

Glenda Dekkema is a freelance writer living in Stouffville, Ontario 

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