Insulated Concrete Forms (or ICF’s) are forms that are built-in insulation that accepts reinforced concrete. These large hollow blocks are stacked like legos and filled with reinforcing bar & concrete. In the end, you are left with a structurally sound wall that is insulated with a vapor barrier and ready for final exterior and interior finishes.
There are three general types of Insulated Concrete Forms construction: flat ICF wall (as shown in the photo above), where the poured concrete surface is flat; waffle grid, where the concrete has varying thickness; and open grid, where the concrete forms a grid.
Benefits of Insulated Concrete Forms
1. Comfort – There will be no drafts or cold spots. ICF homes maintain a constant temperature resulting in smaller energy bills. This is great.
2. Energy Efficiency – Homes built with Insulated Concrete Form exterior walls require an estimated 44% less energy to heat and 32% less energy to cool than traditional wood frame houses of the same size. Consequently, HVAC systems are downsized resulting in short and long term savings.
3. Quietness – Your outside noises are reduced if not eliminated. As a result, you have a quieter home.
4. Environment friendly – No CFCs, HCFCs, formaldehyde’s, and no wood to rot and mold. This is great for allergy and asthma sufferers. Insulated Concrete Forms have a two-hour fire rating and are termite and pest resistant. But most important, they withstand high winds and severe storms.
ICF homes look the same as a wood framed home, but they are completely different because of the exterior walls.
Based on research conducted by the National Association of Home builders Research Center, this publication reports on the results of testing and monitoring done on three homes built in Chestertown, Maryland. The homes, each 1,200 sf, were identical, except for the construction of the exterior walls. Two of the homes were built with insulating concrete forms, the third with conventional wood framing. Results from extensive cost and material analysis, acoustic testing, and energy usage are described.
The ICF homes cost 3 to 3.5% more to build than the comparable wood frame home, based on the sales price of the home. The concrete homes were significantly quieter, testing to a Field Sound Transmission Classification as height as 42, compared to only 34 for the frame home. Energy usage in the concrete homes was approximately 20% lower than the wood frame home. This report demonstrates the superior performance and value achieved in concrete homes at a modest increase in the overall home construction cost of the house.