ICFs help construction go beyond code
As code requirements for energy conservation continue to strengthen, the construction industry relies on building material companies to come up with products that mitigate the effects of heat transfer and air infiltration.
The improvements gained through products like insulation, reflective roofing and window films have made significant reductions in the amount of energy it takes to keep a building heated and cooled.
And then there are innovations like insulating concrete forms, or ICFs, that set a new standard for energy-efficient construction and are growing in popularity as a key component in many of today’s residential and commercial projects.
The concrete wall systems are reinforced with steel and insulated with a double layer of polystyrene foam, combining strength and energy efficiency in individual units that can be arranged in countless designs.
To determine the energy efficiency of a home or building, industry leader Fox Blocks suggests considering three factors: continuous R-value, thermal mass and air infiltration.
Continuous R-value is a key attribute of a building’s thermal performance. It refers to how well the wall as a unit resists heat transfer.
In a wood frame house, for example, the R-value of the insulation has to be adjusted because of thermal bridging, to include the lower R-value of the wood framing. So, while a builder may use fiberglass batt rated R-19, the R-value of the wall as a whole will be lower.
With ICFs, insulation is incorporated into the structural elements of the blocks. Instead of layers of various materials with differing R-values, ICFs provide one continuous and consistent thermal value for the structural envelope, exceeding code minimums.
More than half the energy lost in a traditional wood frame structure is due to the way heat passes through the various layers: wood framing, fiberglass batt and exterior finish.
As energy efficient as any individual component may be, there’s the potential for heat loss in every gap between layers. Adding blown-in or sprayed-on insulation can reduce infiltration, but it can’t eliminate it completely: wood frame buildings typically have 50 percent more air infiltration than ICF buildings.
Thermal mass is the scientific term for thickness. Because walls made from ICF blocks are considered mass walls, they delay heat transfer, maintaining a more stable inside temperature despite external heat fluctuations.
In areas where nighttime temperatures are considerably cooler than daytime temperatures, the mass concrete within the blocks can release stored heat at night. This considerably reduces the energy needed to heat and cool the building on a daily basis, for the life cycle of the building.
The combination of these three factors creates what’s known as the ICF effect – high-performance structures that require 44 percent less energy to heat and 32 percent less energy to cool than comparable wood-frame houses.
Improving on current code standards
Many structures built to current minimum code standards are considered safe, but that doesn’t guarantee its resilience.
Research shows that designing to exceed code pays off. According to the National Institute of Building Sciences, “specific disaster mitigation strategies that go beyond the requirements of the 2015 International Codes model building codes could save the nation billions of dollars.”
The organization’s 2017 Interim Report found that building designs that “exceed select code requirements can save the nation $4 for every $1 spent.”
ICFs don’t just contribute to code-compliance, however. They contribute to structural performance in several ways:
- Contributing to LEED certification.
- Enabling HERS certifications below the national standard for zero-energy-ready homes.
- Providing a healthier environment in terms of air quality and acoustics.
- Standing up to the strongest wind storms.
Companies: Fox Blocks