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Building Houses to Withstand Storms
When hurricanes howl, the greatest danger to people and property is flying debris. Researchers for the Wind Engineering Research Center at Texas Tech University have proof 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. To duplicate hurricane-‐like condi2ons in the laboratory, researchers shot wall sec2ons with 15-‐pound 2 x 4 lumber "missiles" at up to 100 mph, simula2ng debris carried in a 250 mph wind. These condi2ons 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 sec2ons of concrete block, several types of insula2ng concrete forms, steel studs, and wood studs to rate performance in high winds. The sec2ons were finished as they would be in a completed home: drywall, fiberglass insula2on, 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 liNle or no resistance to the "missile." The 2 x 4 ripped through them. Reinforced concrete homes have proven their wind-‐resistance in the field during tornadoes and hurricanes. In Urbana, Illinois, a recently constructed insula2ng 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. Monolithic Domes, which are made of concrete and rebar, have proved especially strong. The sturdy concrete construc2on combined with the dome shape make these innova2ve homes nearly impervious to tornadoes, hurricanes, and earthquakes.
Points to Remember in Building a Home that can Withstand Storms: • Architectural plans should be checked to confirm that a two-‐story home has
connec2ons between the first and second story and that everything above the first floor is anchored securely to the founda2on.
• Remove any metal, stone or large decora2ons from the exterior design. These will
become projec2les in strong winds. • The loss of the roof will mean severe damage to the home. Money spent on
addi2onal roof improvements will result in the most safety. Avoid long, heavy shingles and 2les in roof construc2on. Select flat, light shingles for roofing materials. Secure fastening is essen2al to keeping the roof aNached to the walls of the home.
• For the most protec2on, select impact-‐resistant windows designed for hurricanes. • Steel doors should be aNached to a secure frame with at least three hinges. Commercial
rated deadbolts are the strongest against winds. Install an addi2onal bolt to the top door frame. Sliding pa2o doors are not safe in tornado winds. Install one door with plas2c glazing and steel construc2on in place of a large slider door.
• A garage door ripped from the building will allow winds to create damage. Even with
metal s2ffeners, double garage doors will be at risk in tornado winds. Two heavy-‐duty, single-‐car garage doors are preferable to one large door.
• The founda2on is the key to securing the house, and all bracing and anchoring should aNach to it.
• A home built for tornado protec2on offers a basement, shelter, or other room
below ground. A separate safe room is the safest place in a tornado. It must have at least a tornado strength metal door, thick ceiling and secure walls. Objects and debris may be hurled at the room from all sides, so all materials must be rated as tornado safe.