Building owners, architects, engineers and contractors are under increasing pressure to meet stringent new energy codes, even while facing competitive markets and having to contain costs of the construction value stream.
This is causing the construction industry to rethink building design and to develop innovative building construction methods that address these concerns. At the same time, cost pressures will always be present so any construction method that can compress construction timelines and allocate labor to the best task for efficiency and cost will be pivotal.
Additionally, contractors and fabricators are always looking for ways to decrease site liability and to manage a variety of liability factors including injuries from things such as ladder falls and fire prevention.
Insulated Concrete Forms (ICF) are one way to improve building energy efficiency while minimizing construction labor costs.
An insulated concrete form, or ICF, is a system of reinforced concrete midrise formwork wall that utilizes integral thermal insulation as both the formwork and permanent thermal insulation. This type of structural system can be used for interior walls, exterior walls, floors, or roofs and can even incorporate plumbing or electrical elements. ICFs are constructed using insulated concrete form units that are stacked together and connected in a Lego-like fashion, without mortar, and then filled with reinforced concrete.
ICF’s provide many benefits including:
Decrease in Building Time (Reduction in Construction Costs)
Increased Site Safety (No wooden forms and hazards)
Quiet Assembly (Not using wooden forms and associated noise of assembly)
Fire Resistance – (Concrete walls have an inherent fire rating versus a wood wall that is combustible and requires sheetrock to obtain a fire rating)
Seismic Resistance (Concrete is much more resistant to lateral seismic/wind forces)
Integral Thermal Insulation
Costs are reduced through the reduced need for labor, although the labor needs to be skilled in order to prevent cracking of the concrete, provide stable formwork and avoid other problems when pouring the concrete. The costs are usually lower than traditional methods such as steel studs. Wood studs are less expensive than ICFs, but only slightly and they do not provide the resistance to vermin and termites that concrete provides. Heat loss or gain is minimized through minimal air leaks and the insulated concrete (increased thermal resistance). Additional layers of insulation can be applied continuously to further enhance the insulation efficiency.
Insulated concrete forms are ideal for buildings that are low to mid-rising. The highest ICF building is twenty three stories high -on the higher side- in Waterloo, Ontario. They have been used for curtain wall buildings with spandrel panels, but are optimal for buildings with high amounts of solid wall with punched openings. The walls can extend over forty feet high, unsupported if assembled correctly. There are also a range of thicknesses which can go from four inches to twelve inches (they are available in four, six, eight, ten, and twelve inch thicknesses generally). The thickness used should be based on the loading applied to the wall and need for lateral seismic/wind resistance. In fact some owners select ICF construction specifically for risk management in areas where tornadoes and hurricanes are present.