Thursday, August 25, 2011

surviving hurricanes

Carol M. Highsmith's America,
Library of Congress,
Prints and Photographs Division.
Hurricane Irene is slowly passing offshore, leaving us with rain and clouds, but nothing unusual for a summer in the sub-tropics. The storm may cause catastrophic damage farther north, however, and we are hoping our friends in the Carolinas, the mid-Atlantic and New England are safe over the next few days.

So how do you design buildings to survive winds in excess of 150mph and torrential rain?

We're not in an area vulnerable to storm surges (which is what probably did the most damage to the Waffle House pictured here), so we don't need to elevate our house above the wind-driven wall of water coming off the ocean. Nonetheless, we are mindful of flooding, and we've designed tin box so that the floor is approximately two feet above the 100-year flood level. We've also designed the site to allow heavy rains to quickly percolate into the soil, rather than run off into the street.

Like every building built in Miami-Dade County, our home is required by code to withstand both hurricane-strength winds and the impact of wind-driven "missiles." Every exterior material and assembly has been approved by the county after being subjected to simulated wind and impact, as well as wind-driven rain. This includes our windows and doors, which will allow us to weather a storm without having to install shutters. One advantage to not using traditional roofing tiles is that our materials are less likely to detach (and become dangerous airborne debris) in high winds, and we decided to use adhesive solar panels because they are both easier to secure to the roof and less likely to compromise the roof's weathertight seal in high winds. The great tensile strength of the steel structure and the fastening systems used to install the roofs and walls will help the house remain intact and in place, even when the wind creates enough uplift to launch a 50-ton passenger jet.

We're also concerned about the habitability of the house after a storm. Solar panels can't power a house by themselves, and since we opted for a grid-tied system (rather than one with backup batteries), we need to install a gas-powered generator to supplement the solar panels when the utility's electricity supply is interrupted. And while it is less common to lose water supplies after a hurricane, we hope that our cistern and filter system will provide drinking water in case the municipal system fails.

For everyone up north, please stay safe. And keep an eye on the hurricane tracker.

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