Insulating Concrete Forms (ICF) is a type of formwork for reinforced concrete commonly made with thermal insulation (polystyrene or polyurethane foam) that acts as a permanent interior and exterior substrate for roofs, floors, and walls. The forms themselves are permanent interlocking modular units that fit together like Lego blocks which are then filled with concrete, creating more high-performance buildings than its traditional counterparts. The self-supporting foam blocks used in ICF construction lock together to create a structure that is strong enough to hold the poured concrete.
Where ICF began
The ICF technique was introduced in Europe after World War II as an affordable and durable alternative to rebuild damaged buildings. As more energy efficient and natural disaster resistant building codes are being introduced by many developing countries, ICF has become the prevalent construction technique particularly for high-performance residential and low rise commercial construction. While there was a steady increase in the use of ICF construction after the 1970’s, ICF construction has now become a part of most building codes in the developed world due to it being the strongest and most energy efficient wall system available for residential and commercial construction.
The result of Insulated Concrete Forms is an R-17-plus wall that contains a solid concrete mass core with permanent insulation on both sides. The foam blocks and panels also allow for interior and exterior finishes to be easily attached, along with the ability for ‘let-in’ mechanical runs such as wiring and plumbing without cutting into the concrete core. Despite this, any type of wall penetration or pipes running through the walls needs to be accounted for before any concrete is poured.
A better alternative to traditional buildings
Not only is ICF a better alternative for walls, but also for floors and roofs alike. For example, ICF flooring can weigh up to 40% less than traditional concrete flooring and can be constructed independently or designed to form a continuous reinforced structure with the buildings walls. Furthermore, the polystyrene and polyurethane foam used in ICF doesn’t burn and add fuel to the fire. Most manufacturers of ICF add flame retardant to the foam, making it essentially self-extinguishing.
Costs involved with ICF
While ICF will cost more initially (approximately $3 – $5 per square foot when compared with traditional wood framing units), the cost savings in energy achieved throughout the life-cycle of the product will certainly offset the higher initial costs.1 As a result, ICF are being used by contractors to qualify for energy credit and other types of ratings such as LEED.
The advantages of using ICF over other traditional methods such as wood, masonry, or concrete, is that not only does ICF provide a continuous insulation and sound barrier, but also a backing for drywall on the inside, and lap siding, stucco, or brick on the outside.
Other advantages of ICF
Some additional advantages that Insulated Concrete Forms provide include:
- ICF receive R ratings from R-17 to R-26 as opposed to a rating of R-9 from wood framing
- ICF can be used on buildings and walls greater than 40 feet tall
- ICF reduce infiltration by up to 50% when compared with wood framing
- ICF are resistant to mould and mildew problems
- ICF have double the sound resistance than wood framing
- There are no vapour barriers required with ICF since the insulated forms act as natural moisture barriers
- Inserting utilities into ICF walls is very simple and reduces labour costs.
- The foam used in ICF will not attract rodents or insects because there is no food value to them
As you can see, there are many reasons why ICF construction is best technique for residential and commercial buildings. Not only will your walls and floors be more insulative, energy efficient, sound resistant, and fire resistant, but your environmental footprint will be significantly reduced.
If you’re interested in using ICF for your next project, get in touch with the formwork specialists at Uni-Span by phoning 1300 882 825, or visit our website for additional information.