Tuesday, May 3, 2011

Hurricane Season, Green Roof Design and Negligence

Hurricane and cyclone season is here.  The month of May marks the time each year when the National Hurricane Center says potential for tropical storms begin.

Residents of areas prone to cyclones are familiar with the damage high velocity winds can do to buildings and especially roofs.  It is important that any green roof design installed on structures in Florida or other tropical climates subject to storms be fully tested with hurricane simulators for resistance to blow off and destruction.

Hurricane testing of green roofs is important for several reasons.

University of Florida Hurricane Simulator

First is the health, safety and welfare of people.  Placing any object on a roof not permanently attached is a violation of many building codes and can cause serious damage when blown off in high winds.

Parapets and other wind breaks around flat roofs may help up to certain speeds but trays, mats, pots or containers must be permanently attached.  This means each pot and each tray.  Otherwise liability in negligence may exist (consult your construction tort attorney) if the system blows off and causes damage.

Hurricane simulation testing is not the same as wind tunnel testing.  Be sure your green roof system has been tested out-doors on an engineer designed roof testing system with a wind turbine process.  Wind tunnel testing may not offer sufficient design support to protect against negligence (again consult your attorney).

Secondly, a good designer wants to know if the plants they are specifying will hold up in hurricane conditions.

Many plants may loose upper leaves but their root systems stay in place and they regrow quickly.  There are many good reference articles available on the when concerning right plant selection for hurricane prone areas.

I like built in place systems for hurricane prone areas.  Unless modular systems are permanently attached - I suggest permanently attaching each tray with adhesive - and a blow off occurs with resulting damage - then the issue of tort liability potentially arises (consult your attorney).  In our litigation prone society it is prudent to always hurricane test green roof systems before specifying and installing in those areas possibly subject to tropical storms.

With hurricane season here, now is the time to educate ourselves about proper design and installations for green roofs in cyclone prone areas.

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