Concrete Homes - What the Research Says

Wind testing shows how concrete walls hold up in a hurricane

These insulating concrete panels will be used for exterior walls.
These insulating concrete panels will be used for exterior walls. Photo by Johner/Johner Images/Getty Images (cropped)

When hurricanes howl, the greatest danger to people and property is flying debris. Carried at such intense velocity, a 2 x 4 piece of lumber will become a missile that can slice through walls. Researchers for the Wind Engineering Research Center at Texas Tech University say that concrete walls are strong enough to withstand flying debris from hurricanes and tornadoes. According to their findings, homes made of concrete are much more storm-resistant than houses constructed of wood and steel.

The Research Study:

To duplicate hurricane-like conditions in the laboratory, researchers shot wall sections with 15-pound 2 x 4 lumber "missiles" at up to 100 mph, simulating debris carried in a 250 mph wind. These conditions cover all but the most severe tornadoes. Hurricane wind speeds are less than the speeds modeled here. Missile tests designed to demonstrate damage from hurricanes use a 9-pound missile traveling about 34 mph.

Researchers tested 4 x 4-foot sections of concrete block, several types of insulating concrete forms, steel studs, and wood studs to rate performance in high winds. The sections were finished as they would be in a completed home: drywall, fiberglass insulation, plywood sheathing, and exterior finishes of vinyl siding, clay brick, or stucco.

All the concrete wall systems survived the tests with no structural damage. Lightweight steel and wood stud walls, however, offered little or no resistance to the "missile." The 2 x 4 ripped through them.

Recommendations:

Reinforced concrete homes have proven their wind-resistance in the field during tornadoes and hurricanes. In Urbana, Illinois, a recently constructed insulating concrete form home withstood a 1996 tornado with minimal damage. In the Liberty City area of Miami, several concrete form homes survived Hurricane Andrew in 1992.

In both cases, neighboring homes were destroyed. In the fall of 2012, Hurricane Sandy blew apart the older wood construction homes on the New Jersey coast, leaving alone the newer townhouses built with Insulating Concrete Forms (ICFs). See Family Rides Out Sandy in ICF Home on ConcreteNetwork.com.

Monolithic Domes, which are made of concrete and rebar in one piece, have proved especially strong. The sturdy concrete construction combined with the dome shape make these innovative homes nearly impervious to tornadoes, hurricanes, and earthquakes. Many people cannot get over the look of these homes, however, although some brave (and wealthy) homeowners are experimenting with more modern designs of these dome-shaped structures.

Researchers at Texas Tech University recommend that houses in tornado-prone areas build in-residence shelters of either concrete or heavy gauge sheet-metal. Unlike hurricanes, tornadoes come with little warning, and reinforced interior rooms can offer more safety than an exterior storm shelter.

Concrete and Climate Change—More Research:

To make concrete, you need cement, and it's well-known that the manufacturing of cement releases great amounts of CO2 into the atmosphere during the heating process.

The building trade is one of the largest contributors to climate change, and cement makers and the people who purchase their product are some of the largest contributors to what we know to be "greenhouse gas pollution." Research on new production methods will no doubt be met with resistance from a very conservative industry. At some point consumers and governments will make new processes affordable and necessary. Some of the research includes:

  • Calera Corporation of California has focused on recycling CO2 emissions into the production of a calcium carbonate cement. Their process uses the chemistry found in nature—what formed the White Cliffs of Dover and the shells of marine organisms?
  • Researcher David Stone accidentally discovered an iron carbonate-based concrete when he was a graduate student at the University of Arizona. IronKast Technologies, LLC is in the process of commercializing Ferock and Ferrocrete, made from steel dust and recycled glass.

Next Steps:

Want to build your home with concrete? You'll find house plans, illustrations, and lots of information at Concrete Homes, the Website for the Portland Cement Association, and Building with ICF's on the Website of the EPS Industry Alliance, the trade association representing the expanded polystyrene (EPS) industry.

For help planning and constructing a Monolithic Dome home, visit the Monolithic Dome Institute.

Why You Might Want to Hire an Architect:

Building a home to withstand nature's fury is not a simple task. The process is neither a construction nor design problem alone. Custom builders can specialize in Insulated Concrete Forms (ICF), and even give their end-products safe-sounding names like Tornado Guard, but architects can design beautiful buildings with material specifications for builders to use. Two questions to ask if you are not working with an architect are these:

  1. Does the construction company have architects on staff?
  2. Has the company financially sponsored any of the research testing?

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