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Definition

rooftop_6.jpg
Rooftop pavers. Image by Unity Surfacing Systems

Rooftop pavers are an architectural element that may be composed of concrete, stone, rubber, or a number of highly durable materials that is used to cover exterior horizontal surfaces of buildings.[1]


Issues Addressed


High wind events, such as hurricanes and tornadoes, can turn rooftop ballast into projectile elements which are a danger to public safety. Findings from roofing studies done after Hurricane Katrina found reoccurring patterns of scour such as as the one pictured at right. At speeds of over 100 miles per hour, small stones and gravel become bullets that can cause

reat damage and bodily harm to anything it in its path.[2] [3]

Considerations

Rooftop pavers are a good option for flat roof ballast applications. Although, even pavers
rooftopgravel.jpg
could become airborne under the right conditions and any potential source of lift could turn them into missiles. Wind tunnel studies have shown vortices occur at building edges and corners that are substantial enough to create uplift capable of moving pavers. Pavers should be interlocked and fastened wherever possible.[4]

Consider a ballast paver termination bar to secure edges:
terminationbar.jpg
Demonstration of paver termination bar at rooftop edge. Image by Firestone
[5]



Applications


Proper application of alternatives to stone or pebble ballast are found commonly through New York City. Roofing specialist and installers are well aware of wind risks and should be consulted when roofing choices are made in the design phase.[6]


References


  1. ^ Hanover Architectural Products. Advertisement. Hanover Roof and Plaza Pavers 2011: 1-24. http://www.hanoverpavers.com/pdfs/roof11.pdf
  2. ^ Roofing Industry Committee on Weather Issues. Hurricane Katrina Wind Investigation Report. Rep. N.p.: Oak Ridge National Laboratory, US Department of Energy, 2007. http://www.ricowi.com/docs/reports/RICOWI_Katrina_Report.pdf
  3. ^








    Urban Green Council, comp. Building Resiliency Task Force. Rep. New York City: n.p., 2012.http://www.urbangreencouncil.org/servlet/servlet.FileDownload?file=015U0000001Eybd
  4. ^
    Aly, Aly M., Girma T. Bitsuamlak, and Arindam G. Chowdhury. "Full-scale Aerodynamic Testing of a Loose Concrete Roof Paver System." Engineering Structures 44 (2012): 260-70. Web. 9 Nov. 2013. http://wow.fiu.edu/wp-content/uploads/2013/03/24.-Engineering-Structures_2_Roof-Pavers.pdf
  5. ^







    Firestone. Ballast Paver Design & Installation Guide. Rep. http://technicaldatabase.fsbp.com/downloadFile.ashx?fileId=%5Bfid=19539%7Cpid=674%5D
  6. ^









    Hanover Architectural Products. Advertisement. Hanover Roof and Plaza Pavers 2011: 1-24. http://www.hanoverpavers.com/pdfs/roof11.pdf