Insulating Concrete Forms

Essay by PaperNerd ContributorCollege, Undergraduate October 2001

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INSULATING CONCRETE FORMS ICFs (Insulating Concrete Forms), the new wave of the millennium. All in all, there are over 40 different brands sold in North America.

These lightweight foam blocks or panels can be stacked into shape to create the exterior of basements, homes, and low-rise commercial buildings. ICFs have been proven to be very economical. They show this by being more energy efficient, stronger, quieter, and more comfortable than the traditional home.

The process is fairly easy also, first the foam forms are set in place and reinforced with rebar. Most ICFs are set in place by dry laid courses with quick snapping rebar placement. Then the forms are ready for alignment. Some certain ICFs require that you use a WASS (a wall alignment scaffolding system). Once they are aligned, the forms are ready for the concrete, which is usually poured using a pump truck for even pours. After the walls have set up, the outside is ready for siding, stucco is a very popular method that can be put directly on the foam, which can make the finishing process even faster.

The siding is to be screwed directly to the ICFs. (Screws are required). Inside the foam, is high impact plastic strips, used as studs. The walls on the inside are also ready for whatever you want to use, (drywall, etc.) because the plastic strips are on the inside too.

Masonry is also popular choice for ICF home builders. Most ICF companies have certain foam forms that make it possible for a brick ledge.

At first when one looks at ICFs, you might think that the price is quite high, but ICFs have become a very cost effective way to build. A home basement typically costs about 15-20% more than say a poured concrete basement, but if it is finished, it is about the same price. If you were to build a 2" x 6" insulated wall, it would compare to be about the same price. Another main reason why the price equals out is because of reduced energy costs. When building, ICFs reduce wall construction and insulating time by 2/3 to ¾. This also comes in on the builders side, ICFs can be used for almost any design or project, they reduce costs and building time. Better for the builder and the owner. A important point is that the finish product integrates form work, insulation, studs/strapping, vapor barriers, air barriers, and sheeting into one cost and time efficient building system. But after all, the total price could vary from 1-5%, for number of different reasons.

The insulating value of the concrete block wall is approximately: R2.5, where the value of most ICFs is R20+. Therefor if you have a heated basement, your heat loss is going to be considerably reduced with the ICFs. See pic1, This picture illustrates how many BTU's are lost per hour, comparing a concrete block wall and a ICF.

Another plus that the ICFs can offer is their fire resistance. Not only is the 5.75" poured concrete wall fire resistant, but the foam which is 4.5" is EPS material. Which is Flame Retardant Expanded PolyStyrene. This could be very good for some light commercial buildings that could be subject to fire hazards. Also in some areas, this fire resistant material may help people get lower insurance and valuable rebates.

For the environmental people, ICFs replace the lumber products, they are non-toxic, contain no CFC's, HCFC's, HFC's, will not decay, 100% recyclable, and are non-nutritive to pests and rodents.

ICF walls when cured properly, along with correct rebar placement can make the wall about 30% stronger than conventional walls. And the concrete curing process increases strength 50% at 180 days.

If electrical and plumbing is needed in the walls, a grove can be made using a router or a hot knife. Some contractors have used conduit, inserted into the walls and installed electrical boxes in the foam before the concrete is even poured, in lifts of 2-4 feet, working entirely around the whole wall.

When these walls reach their full maturity, they can withstand winds up to 160 mph.

It is highly recommended that one builds the whole house out of ICFs. It can be done in a two step process, just as if you are building a traditional home. Do the first level and then the second, taking the proper measures to connect the two pours. The main reason to build the whole house out of ICFs is for the energy savings. If just the basement is built out ICFs, you can expect to save 30-40% of not only the heating bill, but the cooling bill also. But if the whole house was built out of ICFs, savings could reach up into 70%. Which in turn would allow a smaller furnace and air conditioning unit.

Some other things that ICFs have over conventional concrete walls and regular stud walls is that many people believe that ICFs are less susceptible to noise from the outside. And being that the walls are app. 5-6" wide and with the foam, the walls make very large window sills, great for plants.

Out of all the companies that make ICFs, I choose about four of them to do my paper on. I also used a article that told about the general requirements and properties of ICFs. All of my information, may not be the same for all the different types, but I used some of the top manufactures information.

ICFs have been around for a few years, but I believe that in the next few years, they will really take off. It seems to me that the ICFs make the project go much faster, whether it be commercial or residential construction.