breakaway walls
Thursday, June 19, 2014 at 6:49AM
stephanie in climate, structure, weak systems, weather

Damage from Hurrican Ivan, 2004, in the southeastern USA where breakaway walls are necessary and mandated.

This structural detachment of structure and skin is very helpful in extreme weather: in hurricane-prone coastlines houses have breakaway walls which are ground level enclosed areas for parking or storage, where the enclosing walls will actually break away from the structure when hit by high winds and water.  The house is instantly piloteed, water and wind rush right under it.  Breakaway walls are bylaws in many areas, and there is a FEMA manual that outlines specifications. The principles appear to apply only to ground floors; the house itself is conventional construction where walls are meant to protect, not flee.  

Because of our northern climate, all our woodframe houses sit on basements that act like concrete boats: they resist frost heaving but in a flood fill up with water immediately.  And every time there is a tornado in a non-tornado zone such as happened in southern Ontario last week, the houses are deconstructed leaving piles of studs and shredded plywood.  In Places in the Heart, a 1980s movie set on the prairies during the Depression, a tornado was coming and Sally Field rushed about the house opening all the windows before taking the children into the storm cellar. The house was made as transparent to the wind as possible. A storm cellar is accessible from outside the house, no convenient basement stair, and so even if the house is blown apart, the cellar is a separate underground bunker.  This was in The Wizard of Oz, which we've forgotten.

In this new era of violent weather, our bulwarks against traditional weather where the worst that happens is that it gets very very cold — three weeks of -30, no problem, the houses are snug.  Our houses have always been built to resist — we feel the whole house ought to be a storm cellar — rather than to bend.  We are getting new weather, we are going to have to rethink it all. 

Article originally appeared on onsite review (http://www.onsitearchive.ca/).
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