concrete forms (ICFs) are interlocking modular units
made of expanded or extruded polystyrene (EPS or XPS) that are
dry-stacked into the shape of the exterior walls of your home.
Reinforcing steel is added and concrete is poured into the ICF
forms. The foam remains in place and becomes part of the wall,
thus providing the insulation value to the wall system. The
result is a home that is comfortable, provides sound absorption,
is energy efficient, and has strength, durability and design
Houses built with ICF exterior walls
require an estimated 44% less energy to heat and 32% less energy
to cool than comparable frame houses. These are not one-time
savings; they continue year after year.
The thermal mass (the ability to smooth out
large swings in temperature) of concrete contributes to the
reduction in heating and cooling costs. Since the energy needed
to heat or cool is less, the size of furnaces and compressors
can be smaller, reducing equipment costs.
The CTL report of February 1, 1996 of 338
cities across the U.S. and Canada gave an equivalent performance
R-value of ICF for the City of Ottawa of R-28.7. The CTL report
was based on a wall with a concrete thickness of 5 inches and
EPS thickness of 2 inches. For a typical wood frame wall to have
the equivalent performance R-value, the R-value of the wood
frame wall would have to be greater than R-50. The R-value of an
average wood frame wall ranges between R-9 to R15 (the R-value
fluctuates depending on how many windows, doors, storeys, etc.
Almost half of energy loss can be found
through the foundation and above-grade walls. With an ICF home,
the outside wall is continuous from the foundation to the eaves
and as floors are hung on the inside, there is no break in the
walls as compared to a traditional frame house where there are
hundreds of joints between exterior wall studs, floor plates,
and windows and door frames.
High Indoor Air
Insulated concrete forms prevent air
movement, thus creating an airtight seal around the entire
perimeter of the building and preventing the entry of dust,
pollens and pollution. The use of EPS panels also eliminates all
airborne glass fibres (commonly found in traditional fibreglass
insulation) and insulation settlement caused by fibreglass
Concrete is inert and non-toxic. As it is
naturally waterproof, it doesn’t need volatile organic-based
treatments. No CFC’s, HCFC’s, formaldehyde or any chemicals are
used in the manufacturing process and no off-gassing is present.
ICF homes have even temperature, fewer
drafts, fewer hot and cold spots, and consistent
Conventional frame homes carry an STC
(sound transmission class) rating ranging from 36-38. ICF homes
carry a sound transmission class (STC) ranging between the high
40s and the low 50s. As the STC is based on a logarithmic scale,
this means that loud sounds such as vehicles, airplanes and
trains from outside are reduced to a whisper in an ICF home.
ICF homes are built using reinforced
cement. Reinforced concrete buildings are very strong and are
less susceptible to damage caused by the forces of nature such
as earthquakes, tornados and hurricanes.
Concrete walls are resistant to rust, rot,
burning, light, oxidation and pests. There are no exterior wall
cavities for pests, insects or mould to live in. ICF walls have
little or no maintenance or repair.
Depending on the type of finished used, ICF
walls provide two to three hours of fire protection. For
example, a typical 6-inch concrete wall with a gypsum board
interior and a stucco exterior will provide a minimum fire
rating of three hours.
ICF homes retain their value for a longer
period of time due to the fact they’re sturdier, stronger and
require much less repair and maintenance than conventionally
An ICF home reduces energy consumption on
average by 30-50% monthly, which translates to an equivalent
reduction in harmful emissions.
Based on a 100-year life cycle, ICF homes
can reduce carbon dioxide emissions by over 100,000 kg, assuming
40 kg/GJ for power generation. This reduction greatly outweighs
the emissions caused by manufacturing concrete, which is
estimated at 2,000 kg according to the 1994 study by Forintek.
In building an ICF home, construction waste
is typically 2-5%, much less than other wall materials, and
benefits the environment by decreasing the waste going to
landfills. Every one tonne of methane gas produced by
landfilling practices can be counted as 20 tonnes of CO2 being
produced, contributing to global warming.