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In determining whether the damage is from poor construction or the tornado itself, Haag Engineering Co. Structural Engineer and Meteorologist Tim Marshall looks at three factors: anchors, braces and connections.
"There are three critical areas for connections: wall to foundation, wall to wall and roof to wall"

"The [Dallas area] tornado exploited poor connections by tearing away roofs and toppling walls"

"We found 'cut nails' used around the perimeter of the house to secure the wall bottom plate to the foundation. Still, more homes were attached by shot pins. Some homes [were] anchored with bolts [that] did not have nuts or washers to secure the wall," Marshall said.