In the article "The hurricanes of 2004," September issue, page 22, Thomas L. Smith, president of TLSmith Consulting Inc., Rockton, Ill., provides some good insight into the performance of roofing materials during the 2004 hurricane season. However, the Tile Roofing Institute (TRI) must take exception to some of the comments in the article.
Based on viewing only a few tile roofs, Smith says tiles did not "perform as predicted" and the industry's installation manual predicted performance that was not achieved. These statements infer uplift values used by the industry are invalid. In fact, the fastening tables included in the third edition of the Concrete and Clay Roof Tile Installation Manual, published by the Florida Roofing, Sheet Metal and Air Conditioning Contractors Association (FRSA) Inc. and TRI, are based on extensive testing, including full-scale wind tunnel testing in winds exceeding 125 mph (56 m/sec) and static uplift testing in winds more than 150 mph (67 m/sec). The tables provide tested resistance values for mechanical and adhesive-set systems.
TRI sent teams in 2004 to evaluate the performance of tile roof installations in Florida and found roofs that were properly installed according to the manual did perform well. We agree there was improper workmanship in many of the failed roofs installed after the 1997 code changes.
Furthermore, the article does not provide enough details to support its conclusions about performance. There are many aspects to consider when properly evaluating a roof assembly for wind damage, including wind speed, gust speed, wind direction, exposure, roof height, roof slope, proximity to surrounding buildings, down drafts and tornados.