After The Storm - A Guide to Better Re-Roofing
Hurricane Ida came ashore at 11:55 a.m. in Port Fourchon, Lousiana with sustained winds of 150 miles per hour. Many of the houses in the coastal areas of Louisiana were constructed long before the state adopted the International Residential Code in 2006 following Hurricane Katrina (2005). Structural wind damage to many of these buildings was extensive and devastating within the path of the storm.
But, beyond these structurally compromised residences, wind damage to roof coverings was common throughout southeast Louisiana. While these homeowners were fortunate to escape significant structural damage, roof openings exposed the interior of their homes to hours of rainwater and have created additional difficulties as they wait for roofing, drywall, and additional repair materials to restore their homes and lives to normal.
The Insurance Institute for Business & Home Safety has performed extensive studies into reducing and preventing damage to buildings from storm events by going over and above the current building code requirements. Following this guidance and choosing the right products while re-roofing your house could prevent interior damage during future hurricanes. For information, you can also go to the IBHS website for a re-roofing checklist.
RE-NAIL THE ROOF DECK: The attachment of the roof sheathing is not only a key to keeping rainwater out of the house, it is an integral part of the structure. Many of the catastrophic structural collapses begin with the loss of roof sheathing. At the gable ends, re-nail the sheathing with 8d Ring Shank Nails at 4 inches on center in the 4 feet neat the end of the roof. If you have a hip roof, a 4-foot-by-4-foot eave corner should be nailed with 8d Ring Shank Nails at 4 inches on center. The remaining roof sheathing should be nailed with 8d Ring Shank Nails at 6 inches on center.
SEAL THE ROOF DECK: As many people have found out, when shingles come off the underlayment (roofing felt) also comes off. When this happens, the rainwater drains between the gaps in the wood roof sheathing, wetting the roof insulation, ceiling drywall, and can cause damage throughout the interior of the house. Installing self-adhered underlayment (often called "ice & water shield") provides a water-resistant barrier in case the shingles are blown off during a storm. Products such as Owens Corning Titanium PSU30 are specifically designed to be installed directly over OSB roof sheathing without a primer. Be sure that your roofing contractor has removed or set all of the old nails are roofing debris and the roof sheathing is fully dry before installing the underlayment.
CHOOSE A BETTER SHINGLE: While most of today's "architectural shingles" are a superior product to the three-tab shingles being installed a few decades ago, they are still prone to blow-off during strong wind events. ASTM D7158 is a test method for classifying the wind resistance for asphalt shingles. Look for shingles that are listed as ASTM D7158 Class H (150 miles per hour) when choosing a new shingle for your roof - note that shingle warranties and wind ratings may be different. Shingle uplift and damage are primarily dependent upon the quality of the seal where the shingles overlap. However, some manufacturers have begun including additional reinforcement along the nailing strip to prevent nail tear-throughs during windstorms. Owens Corning includes their SureNail reinforcement on the Duration Series line of shingles. While not all installations require it, consider using a manufactured starter strip at the roof eave rather than the typical practice of using cut-down shingles.
WHAT'S THE COST?: The extra labor and higher quality materials associated with a more storm-resistant roofing system do come with a higher cost. Each roof installation is slightly different and will be affected by roof height, roof slope, and other factors such as labor markets and material availability. However, as an example of the typical costs associated with this improved roofing system, a roofing company in Charleston, South Carolina provided a cost comparison from a recent roofing replacement (January 2021).
The 1-1/2 story residence had a roof that required 4,500 square feet (45 squares) of shingles. The quote, including standard synthetic underlayment, new flashings, ridge vents and appurtenances was for $18,932.05 ($420/square) to install Certainteed Landmark shingles. The Landmark shingles are a common "architectural shingle" warrantied for 130 miles per hour wind exposure. The cost of optional upgrades was $4,950.00 to re-nail the sheathing and install "ice and water shield" ($3,410.00) and install Owens Corning Duration shingles with SureNail ($1,540.00). The total installed cost of the "upgraded" roofing was $23,882.05 ($530/square). While the additional $4950.00 is no small sum, it is less than many homeowner deductibles and most "named storm" deductibles after a hurricane. When you take into account the relief of returning to your home with little or no damage to the interior, the return on this additional investment may be immeasurable.