Insulated Concrete Forms Withstand Hurricanes
Exterior Walls Resist High Wind, Fire, Termites, and Black Mold
Sep 8, 2009
The average home is composed of wood framing, some sort of siding, and a composition shingle roof. These homes are comfortable, and increasingly more energy efficient, but are often lacking when faced with severe wind, driving rain, and the odd projectile. Insulated concrete forms have been shown to resist debris traveling at speeds of 250 mph (402.3 kph).
Although the 2009 hurricane season entered with a whimper, things are starting to heat up. Currently, tropical storms Fred and Linda are stirring things up in the Atlantic and the Pacific respectively and may evolve into hurricanes. With both coasts being threatened, forward-looking homeowners already have their emergency supplies stashed away.
What are ICFs?
Insulated concrete forms are basically sandwiches. Like the concrete forms used when pouring driveways, slab foundations, and patios, the exteriors portions of the form function to hold the concrete until it's cured.
When used to build the exterior walls of homes or commercial buildings, the forms are building blocks designed by an architect. The exterior of these sandwich blocks are typically a material such as molded polystyrene or an insulating foam.
What is the Exterior Wall Construction Process?
After the forms are designed, built, and delivered to the construction site, the assembly process begins. There will be stubs of re-bar (steel reinforcing rods) projecting vertically out of the foundation. These will give the concrete something to anchor to.
Next, the workers begin putting the form blocks in place. If the foundation has cured, the first course is secured with a foam adhesive. Otherwise, it's set in the wet concrete (called a wet set).
Next, the walls are built up with the blocks and then the walls are plumbed and braced in the same manner used in commercial tilt-form construction. Then the workers insert re-bar down through the hollow blocks according to the local structural building code.
Then all that's left to do is fill the blocks with concrete and screed the top of the wall.
Other Benefits of ICF Construction
This is considered a green building practice. Wood framing is not used so no trees are harvested. Also, since the design is engineered before hand, usually using architectural software, there's very little waste for the landfill.
- A typical fire-resistance time of 4 hours is not unusual so a homeowners insurance discount is possible.
- Termites and other insect pests are not an issue.
- There is no toxic black mold associated with concrete as there is with moist lumber.
- The tight envelope enhances energy efficiency.
It's obvious that this type of residential construction has many things to recommend it and few objections.
References: www.polysteel.com/ae_ben-secure.htm#withstand
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