Recent natural catastrophes throughout the U.S. have forced the construction community to focus on building resilient communities that can withstand and recover from Mother Nature’s worst disturbances. In addition to their inherently environmental qualities, their aesthetic possibilities and their lowest life cycle cost-effectiveness, tile roofs can add yet another immeasurable benefit to the list—resiliency.
The Chicago-based Tile Roofing Institute (TRI) has worked closely with the U.S. Department of Energy’s Oak Ridge National Laboratory, Oak Ridge, Tenn., to conduct testing on tile in extreme, real-world conditions, and through this testing tile continues to show long-term reliance and durability as a roofing material.
According to the Washington, D.C.-based Federal Emergency Management Agency's U.S. Fire Administration, an estimated 374,900 residential building fires are reported each year and cause an estimated $7.6 billion in property loss. Roof tiles and roof tile systems are Class A fire resistant, which includes tests for spread of flame, intermittent flame and the burning brand.
By basic design, the properties of clay and concrete are fire proof. When they are combined with the thermal mass of the product and the natural air circulation under the tile, which reduces heat transfer to the attic during a fire, they provide one of the best fire barriers of a roofing material. Other materials will require the addition of fire-resistant insulating materials to equate to the same fire resistance found naturally in resilient concrete and clay tiles.
Homeowners in high-wind coastal areas annually face the threat of rain and wind damage to their homes. Industry-based testing has shown that with proper attachment, concrete and clay roof tiles can withstand wind speeds as high as 200 mph. TRI recognizes the unique climate challenges of the coastal regions and offers a high winds certification training course for roofing contractors in hurricane-prone areas. The course instructs contractors how to properly install a tile roof, using the TRI Florida Installation manual as a reference guide.
In addition to its installation courses, TRI guided the tile roofing industry’s successful efforts to revise codes for high-wind application requirements for all roofing materials and worked with local building officials to upgrade installation standards following Hurricane Andrew. This guidance will improve overall sustainability for current and future construction for commercial and residential projects. The research work performed after Hurricane Andrew established the basic benchmarks for the best performance in high-wind applications and became the basis for the current code language in all of North America. TRI continues these efforts as it analyzes roof system performance after all major wind events to help the design community better understand where additional focus might help provide increased performance. While hurricane-proof housing may seem like a dream, it will become a reality in the next decade as new and improved building practices and innovative materials are discovered.
Each year many areas of the country are susceptible to devastation from extreme hailstorms. According to FEMA, hailstorms cause approximately $1 billion in property and crop damage annually. The good news is concrete and clay roof tiles can resist damage from hailstones as large as 2 inches, just larger than a golf ball. This defense comes from a tile roof system’s two-layer protection. The primary layer of protection is the tile as it provides a tough water-shedding outer shell, and the second layer is an underlayment of asphalt roofing paper over the roof decking, which protects the inner shell if the tile was struck by extremely large hailstones.
Another great attribute of tile is the ease with which a tile roof can be repaired. Individual tiles can be removed easily and replaced without disturbing the integrity of the surrounding roof system. In many areas of the country, at lower wind-speed designations, only the perimeter tiles need fastening. This allows the tiles to be slid easily upslope and removed in less than a minute. In most cases, the tile, even if broken and cracked, will continue to provide water-shedding capabilities until fixed. Traditional roofing materials do not have the mass of tile and, therefore, such damage will often affect not only the roofing material but the decking material, as well, allowing water damage to occur within the living area.
The U.S. Geological Survey, Reston, Va., reported more than 8,000 earthquakes in the U.S. occurred in 2010 alone. The scale of these quakes varied with more than 90 percent falling below a 3.9 magnitude. Any earthquake can be disastrous regardless of magnitude, and a resilient structure is crucial. TRI’s independent testing at the University of Southern California, Los Angeles, has shown concrete and clay tile roofing systems, when installed according to building code standards and TRI installation recommendations, will far exceed current seismic-load requirements for building materials. Homeowners can lessen their impact through emergency planning and proper building design. The research showed the roofing tiles attached according to TRI’s installation guides will be able to sustain twice what the walls of a home are designed to see. This makes tile one of the most desirable roofing materials in high earthquake areas.
As building owners look to the future, the demand for a truly resilient building structure will be their next focus. During the last decade, we saw the upward movement from durable to environmental. The next wave will be “resiliency” in design that will capture all the properties of these previous categories and add cradle to grave costing, solar and carbon-footprint reduction. TRI is excited to be part of the research and development that will welcome in the next generation of building materials and practices.