On Dec. 26, 2015, the first EF4 or stronger tornado ever recorded in December in Texas made landfall in Garland and Rowlett, suburban towns near Dallas. APA sent a damage assessment team to the area immediately following the storm. The damage assessment team found numerous examples of severe damage, not just in the area most intensely affected by the storm, but also in areas where the tornado winds were not as intense, with damage indicators pointing to wind speeds well below the EF4 rating.
Building failures were attributed to several common structural weaknesses, including poor performance of laminated-fiber sheathing, missing metal connectors, and poor attachment of wall systems to both the roof and the foundation.
While it is challenging to design homes to withstand the most intense tornadoes, there are cost-effective design details that builders and designers can implement to significantly mitigate storm damage in less powerful winds along the edge of the storm’s path. By continuously sheathing walls with plywood or OSB and playing close attention to all connection details, builders can significantly increase the strength and resilience of their homes.
Download Texas Tornado Damage Assessment Report, Form SP-1177, including general findings, 50 images of tornado-damaged homes, and wind-resistant construction recommendations. The report is also available to purchase in print for $2.00.
Source: APA – The Engineered Wood Association