Rethinking codes in a tornado’s wake
| July 13, 2012 |
Building science experts at the University of Alabama and Simpson Strong Tie have released a report detailing the structural building failures that occured in the F-4 tornado that struck Tuscaloosa, Alabama on April 27 last year.
Not surprisingly, they found the majority of damaged structures would have faired much better had they been built to the 2009 International Building Code standards. And had these homes and light commercial buildings been built to standards more common in hurricane prone areas, even more damage could have been prevented.
Some builders are going to argue that bringing new homes and businesses up this level of code would be prohibitively expensive. But it just ain’t so. Hammering down hurricane clips between the trusses and the top plates on your average home wouldn’t take more than a couple hours and maybe cost a couple hundred bucks. The rest of the changes are hardly bank busters and include stronger wall sheathing attachment and better anchoring of sill plates to slabs.
But I’ve seen this happen all too many times. Big builders trying to cut corners legally, pressure local politicians to ammend local codes or to not adopt the current IRC. Makes wonderful sense to the bean counters and bankers, but ‘ve been in these houses before and they’re so flimsy you can feel the whole house shake when somebody slams the front door.
Hurricane Andrew destroyed 90 percent of Homestead, Florida back in the 1980s–in large part because back then Florida homebuilders were setting world records in cheap and shoddy.
So what happens when an EF-4 tornado passes by? The photo above should tell you enough. I’ll just add one of the conclusions from the U of A / Simpson Strong Tie report cited above: the majority of damage in Tuscaloosa was caused by winds that were below the EF scale.