Insulated concrete forms (ICF) consist of two panels of insulating foam held together with polypropylene ties. The panels form a block shape with a hollow space in the middle. The blocks can be stacked on site with steel reinforcing bars placed in the gap. Finally, concrete is poured into the gap and allowed to set. The resulting steel-reinforced concrete structure is incredibly strong and durable.
ICF foundations require less skilled labor than other building methods and reduce the opportunities for human error. ICF blocks are also lightweight and easy to move quickly around a job site. Once in place, the concrete naturally fills the entire gap and both layers of insulation are already in place.
ICF below grade foundation walls require a compatible waterproofing material, which is easily applied directly to the foam insulation.
ICF blocks provide a host of benefits including strength, energy efficiency, and durability. The superiority of ICF as a building material is part of the reason for its increasing popularity. Some of the most popular benefits include:
ICF blocks provide exceptional strength and durability due to their steel-reinforced concrete. ICF construction allows loads to be transferred from throughout the building into the building’s foundation, to keep the building and occupants safe. The incredible load-bearing capacity of ICF construction allows the buildings to even qualify as storm shelters.
Concrete is a naturally mildew and mold resistant material. Insects like termites are not attracted to concrete. With proper attention to water shedding away from the foundation, ICF blocks provide incredible durability with relatively low maintenance.
An ICF foundation cost typically ranges from $20,700 to $38,000, or $18.25 - $31.75 per square foot, with a national average of approximately $29,450. This cost not only includes the ICF forms but also factors in excavation, cement/concrete, rebar, miscellaneous supplies, and labor.
In most cases, a drainage system such as drain tile or a French drain is also installed to provide drainage away from the foundation which helps to keep the foundation in great shape.
The price of an ICF foundation can vary widely based on several factors. These can include design fees, permitting, excavation costs, site conditions, the amount of infill and backfill required, wall height, and the complexity of the foundation design.
Material costs also factor into the total cost of an ICF foundation. For instance, costs for pea stone or gravel, mixed concrete, vapor barriers, and ICF forms all contribute to the overall price. Compared to a traditionally constructed home, an ICF home will often cost about 3% to 5% more.
In a cost comparison, a typical concrete formed and poured foundation wall will require additional interior strapping, insulation , and vapor barrier to meet the same characteristics of an ICF wall. Also note that ICF foundation walls, in most areas, may be designed with a 6" reinforced concrete core size versus a typical 8" poured wall, providing additional cost savings.
Despite the slightly higher initial cost, an ICF foundation can be a wise investment in the long run. An ICF foundation has an R-value of around 22, and can reduce energy needs to heat and cool the basem*nt by up to 45%.
