Insulated Concrete Forms (ICF) are formwork for concrete that ultimately secures in place as permanent building insulation for energy efficient concrete construction. Although the idea and early forms of the product have been around since the 1960’s, the recent “green” movement throughout all industries has revolutionized the demand for ICF in both residential and commercial construction.
ICF forms can be made out of several different materials, including polystyrene, polyurethane, cement-bonded wood fibers, and cement-bonded polystyrene beads. There are 70+ manufacturers for this product, and the assembly of the ICF varies with each. Generally, the components of an ICF include a face shell, form ties, and a reinforced concrete core. The face shell is usually 2” to 2.5” thick and is designed to withstand the pressure of the concrete during placement. The wall ties (rebar saddles) can be plastic or metal and are usually 6”-12” on center. The sizes of the walls are usually 4”-8” thick and are poured monolithically with 2000-4000 psi concrete. A desired slump for ICF concrete is about 6” with aggregate averaging about 3/8”.
Building with insulated concrete forms is fairly easy general construction practice and can be summed up in the following procedure:
- Form the footer
- Stack the block
- Cut block and form bucks for openings
- Insert reinforced steel
- Pour the concrete ( pump truck is recommended)
- Finish the walls
The end results of insulated concrete forms are the pride of the product. The benefits include superior shell strength, extremely high thermal performance, acoustical attenuation, disaster resistance, and low maintenance. The thermal performance includes high R-values ranging from R-18-R-22, and there is virtually no infiltration throughout the walls. The concrete walls have extremely high sound absorption, allowing for comfortable peace and quiet in every room. Because of the concrete strength and ICF shell, the structural integrity of the building will be outstanding. ICF buildings are practically natural disaster proof and will last decades longer than other framed buildings.
According to wikipeida.com, ICF use can reduce your HVAC operating costs from 30%-70%.