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Home Building Articles

Protecting Homes from Hurricanes

Protecting Homes from Hurricanes

July 08, 2009

Hurricanes are one of nature's most destructive forces, as witnessed in 2005 when Hurricane Katrina pummeled the Gulf Coast. FEMA estimates that Katrina killed over 1,300 people, displaced 450,000 people, and wrecked over 300,000 single-family homes throughout Louisiana and Mississippi. Most of the havoc caused by Katrina was flood-related, due to levee failures in New Orleans. Storm surges created waves that were more than 20 feet high in some places and carried debris that destroyed buildings.

Hurricane resistant design

Most structural failures during a hurricane are a result of inadequate design and construction practices. Conventionally, homes have several weak points, such as windows, doors, corners, connections between floors, and connections between the roof and walls, all of which make homes vulnerable to wind damage. Builders need to keep these weak points in mind, applying design and construction methods that enable homes to resist hurricane winds. These general guidelines help ensure a home is built to withstand hurricanes.

  • Build the home low. The lower the home is, the better, because the wind has less area on which to blow and exert pressure on the home.
  • Build a hip roof. Hip roofs reduce winds better than gable roofs.
  • Build a roof with a 5:12 slope. A shallower slope reduces the wind forces against the roof.
  • Build a wind-resistant roof. If you install shingles, use wind-resistant shingles. If you install tiles, attach them with mortar or foam, and secure them with four to six fasteners per tile. They won't be blown off the roof as easily.
  • Reduce the sizes of overhangs. Smaller overhangs are harder for wind to lift up
  • Don't locate windows near corners. Any opening you put in the corners will weaken the home. Windows built at corners make the home more susceptible to being racked out of shape when the wind blows.

Roof sheathing

Builders can use several strategies for keeping the roof on the home during a hurricane. Plywood is preferable to OSB decking, because it's sturdier. High-quality fasteners and hurricane-proof nailing patterns help keep the roof from lifting up. Decrease the spacing of fasteners on the roof deck to 4" on center. Closer spacing keeps the roof more secure to the home and prevents it from lifting up. Use nails and screws with a longer shank and larger head, and use a closer spacing pattern with more nails and screws. It's important to check your work, because you can easily miss areas with a nail gun. To protect the home against water intrusion, the gaps between plywood sheets should be sealed with a peel and stick tape.

Shear panels

In zones with a high risk of hurricanes, conventional wall bracing isn't enough. Shear panels are required at critical areas, usually at the corners. A shear panel is a wall segment that's engineered to resist hurricanes more effectively than the average wall. The strength of shear panels comes from additional fasteners, thicker sheathing, additional studs, anchors, and hold downs. The shear panels can be either constructed at the jobsite or supplied as preassembled units, ready to install. Preassembled panels are a convenient solution for builders, because they're constructed and inspected by the manufacturer. Builders need to worry only about fastening them in place properly and checking the installation.

Reinforced garage doors

As the largest opening, a garage door is the weakest point in any home. Garage doors are typically made of lightweight materials, making it easy for hurricane winds to tear them apart. Once the garage door is destroyed, wind can rush into a home, causing building failure. The best way to prevent damage to the garage door is to install a preassembled reinforced garage door. Several manufacturers offer garage doors that are strengthened with a bracing system of aluminum bars, brackets, and a steel track. These features prevent the door from blowing in.

Storm rooms

Storm rooms provide a place for homeowners to survive a hurricane without injury. Debris, such as signs, roofing material, and small items left outside become flying missiles in hurricanes. Storm rooms are built with stronger materials than standard homes that allow them to resist wind loads and penetration by these flying objects. Some of the materials that have been proven to withstand impact include concrete masonry walls with vertical and horizontal reinforcement, plywood-covered wood stud walls filled with dry-stacked concrete blocks, and steel sheets combined with plywood sheathing and wood studs.

Like shear panels, storms rooms can be built onsite or installed as manufactured units. They're designed to be a "room within a room," so that they will remain intact even if the surrounding home is destroyed. The storm room should be accessible from all parts of the home to allow homeowners to reach it quickly and safely during a storm. The walls should be anchored to the foundation to resist overturning and lifting up. All sides of the room, including the walls, roof, and door, must be able to resist penetration by windblown objects.

Homeowner education

Studies show that homeowners who live in coastal areas are willing to pay more for hurricane protection and peace of mind. In addition to providing buyers with a hurricane resistant home, give them information about what to do after a hurricane strikes to ensure their health and safety.

Make sure homeowners are aware of what needs to be inspected and what precautions they should take before entering their home. They should have the heating and cooling system checked by a service technician before running it. If water has entered the system, mold can be blown through the home if the system is turned on. If the electricity is off, homeowners should have a portable generator on hand to power equipment and remove standing water. In the basement or crawlspace, you can remove standing water by using a wet-dry shop vacuum, an electric-powered water transfer pump, or a sump pump. To aid drying, open windows and doors, and use fans and dehumidifiers. Fans should be placed at windows and doors to blow air out of the home.

To learn more about protecting homes and homeowners from hurricanes, visit: www.fema.gov

*Source: HGTVPro.com