Claudette Reichel, Reichel, Claudette H. | 9/5/2012 1:00:28 AM
The most common wind damage from a storm is to roofing, which in turn, often results in water leakage that can lead to interior water damage and the potential for mold damage. The good news is that today there are products and techniques that can withstand high winds and save the homeowner the ordeal and expense of roofing damage after the next storm.
After a storm, inspect your roofing for loose shingle tabs, cracks, broken or missing tabs, buckling or curling shingles, blistering and areas that have lost most of its granules. Examine ridge vents, flashings of vents, chimneys and other penetrations to make sure they are well attached and flat. In addition, go in the attic to look for signs of roof leaks such as discolored roof decking, especially around vents.
Minor problems may be repairable with roofing cement and extra roofing nails. If you need to replace the roofing, that is a golden opportunity to protect your home with a much more storm-hardy roof.
1. Remove the existing roofing and underlayment down to the decking. This is necessary to provide a smooth foundation for a new wind resistant roof.
2. Replace any damaged or soft roof decking or framing materials.
3. Re-nail the roof decking to rafters, preferably with 8d ring shank nails (0.113” x 2-3/8” with full round head). The ideal nail spacing depends on the roof design and wind risk as specified in the building code, yet testing has found good performance with 6 inch spacing of ring shank nails. Staples are not recommended since testing has shown that they are not very effective at holding down roof sheathing.
4. Upgrade the roofing underlayment to seal the roof deck. Typical roofing felts don’t seal the decking nor provide good protection when shingles are lost or damaged. A sealed roof can be achieved by installing a “peel and stick” roof membrane over the entire roof. Another option is to tape the seams with a 4-6 inch wide polymer modified bitumen tape approved for roof applications, and apply a reinforced, tear-resistant synthetic roof underlayment (strictly according to manufacturer instructions).
5. Buy and install high wind, impact rated shingles with an ASTM D 7158 Class G or H (or ASTM D3161 Class F) for high wind resistance, and a UL 2218 Class 4 for high impact resistance. These are now readily available since hurricane Katrina.
It’s equally important to make sure that manufacturer instructions for high wind installation are followed exactly. Standard installation methods will not provide the rated performance. This generally involves the installation of a dedicated starter strip (instead of the typical practice of turning a shingle upside down) and installing 6 nails per tab in specific locations.