Patricia Skinner | 1/31/2008 1:47:16 AM
Whether you’re house hunting or having a house built, consider the many options available that help protect the structure against severe weather and related disasters. LSU AgCenter Disaster Programs Coordinator Pat Skinner explains a few basic techniques.
– “Get hip” to roofing. A hip roof is much more resistant to high winds than a gable roof. For any style roof, however, Skinner advises using wind-rated shingles or roofing materials that are certified for use in a hurricane region. Also, make sure shingles are installed properly to high-wind specifications.
For added protection against leaks, use an adhesive, flexible roof tape to seal all decking joints and install 30-pound roofing felt (also known as Type 30 or Number 30) or one of the synthetic roofing felts underneath the roofing material.
– Test your “metal.” Hurricane winds cause uplift forces that can remove the roof from the home or the home from its foundation. Skinner recommends reinforcing all the framing connections –from the rafters all the way to the foundation – so they will all hold together.
The most common technique involves installing anchor bolts to hold the bottom sill to the slab plus metal plates and straps, also known as hurricane hardware, to strengthen the connections between the sills, studs and rafters.
“Remember, coastal environments and copper-based wood treatment are corrosive and can lead to rapid deterioration of metal hardware,” Skinner said, advising, “Use connectors made of stainless or double-hot-dipped galvanized steel.”
– “See the light,” install it right. “Proper installation is critical,” Skinner said. “Many roofing failures occur because the shingles were installed improperly.”
Something as simple as using all the required nails in a shingle or hurricane strap can make a big difference. The builder should clearly understand and follow the manufacturer’s installation instructions for any materials used in new home construction.
A number of organizations are available to help the homeowner and builder identify and understand installation techniques not covered in specific product literature.
– “Shutter-up.” The building code requires that windows be protected from flying debris when the building is located in an area where the design wind speed is 120 miles per hour or greater. This protection can be provided by using impact-resistant windows or covering the windows with impact-resistant shutters. Think about adding window protection even if it’s not required.
– Build high, stay dry. For maximum protection, build your home 2 to 3 feet above the base flood elevation, or BFE. Keep in mind that the BFE is an estimate of the potential flood level, and it doesn’t take into account changes that may affect water depth during future floods, such as land subsidence and sea-level rise.
The BFE also assumes that the levees provide complete protection all the time. By building above the base flood elevation, you can increase your margin of safety while lowering your flood insurance premiums.
– Build your house to take a bath. Flooding of the lower levels of a home can weaken the materials and result in structural damage. For parts of the home that are below the BFE – and even higher areas when there is a real possibility of less frequent, longer-lasting floods – build with decay- and water-resistant materials. Good choices include concrete, ceramic tile or brick with waterproof mortar, treated wood and closed-cell rigid foam insulation. They resist damage from floodwaters and the insects that often thrive in wet environments. Before you build, talk to your contractor about your choices for water-resistant building materials.
Contact: Pat Skinner (225) 578-2910 or Pskinner@agcenter.lsu.edu
Editor: Mark Claesgens (225) 578-2939 or firstname.lastname@example.org