Winds of Change
Text by JAMIE FARNY
Market Manager Buildings
Portland Cement Association
WHEN AN EF-5 TORNADO struck Joplin, Missouri, May 22, 2011, it wiped out six square miles of the town. As townspeople faced the scope of the tragedy and the prospect of reconstruction following the devastation, new options were welcomed. Since this was not likely to be the last tornado to come to Joplin, replacing the old homes with something better and stronger became their priority.
Many residents of Joplin made the decision to rebuild their single-family homes using concrete systems for the walls. They opted for insulating concrete form systems (ICFs) that would offer both strength and energy efficiency to create replacement homes that surpass the originals in two key areas of performance. Concrete can be reinforced to withstand high winds. In addition, ICFs result in cast-in-place concrete walls that are sandwiched between two layers of insulation material.
In Joplin, some older residents on fixed income were without homeowners insurance and had to rely solely upon FEMA funds to help with the cost of replacing their homes.
At 1,150 to 1,250 square feet, these were not high-end houses. And while FEMA's contribution was generous, it still wasn't enough. Enter Convoy of Hope, a faith-based relief organization. Convoy of Hope provided the additional money needed to enable these residents to rebuild something similar in size to what was lost, but make the homes better able to withstand tornadoes and other natural disasters.
TF Forming Systems generously partnered with Convoy of Hope to commit to rebuilding up to 18 homes. By November 2012, six homes in Joplin had been completed, and two more started, all using the ThermoForm System ®, a vertical ICF system. It provides two inches of insulation on interior and exterior faces for improved energy and sound performance. Forms are also made with recycled materials. And since the structures are concrete, the method results in a tighter envelope – offering homes with improved indoor air quality.
In the Joplin project, additional steps were taken to assure strong walls able to resist 250 mph winds. Helix fibers were added to the mix. These small twisted steel fibers complement the reinforcing bars used in the walls. The homes include other details, such as breakaway eaves and hurricane straps, to make them resistant to wind damage.
The configuration of TF Forming Systems is somewhat different from many other ICFs. According to the manufacturer, the longer vertical flat panels stack efficiently for shipping. Wall forms can be rapidly erected to heights of 30 feet. The manufacturer typically will cut materials to specification for a project, further speeding up on-site construction, while reducing cutting time and waste to only about 1 percent for an experienced crew. The system allows forming one side of the wall to allow access to the interior wall cavity and rebar cage full height. Accessories designed to join the forms result in strong corners and a stud attachment for finishes. Results have shown that TF Forming Systems are well suited to proper concrete placement procedures, even for taller concrete pours.
"We are proud to have been selected by Convoy of Hope to participate in their mission of restoring hope to the people of Joplin," says Kirk Brown, TF Forming Systems CEO. "Our wall systems are energy efficient and disaster resistant." ch+
ThermoForm System® is a vertical ICF system.
Photos: TF Forming Systems
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