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RE: retrofit existing roof

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The International Existing Building Code – 2003 has requirements based on level of alterations.  There are 3 levels.  Level 1 is removal and replacement of coverings, Level 2 is reconfiguration of space, adding/eliminating windows/doors, new equipment, and Level 3 alterations effect 50% of the building.  With each level there are different provisions.


Level 1 addresses replacement of roofing or equipment.  Section 507.2.1 states “structural components supporting such reproofing or equipment shall comply with the vertical load requirements of the IBC”.


Level 2 gets into stability and lateral loads.  Also, it requires snow drift be considered.


Level 3 states an engineering evaluation an analysis that establishes the structural adequacy ….


Gary W. Loomis, P.E., Senior Structural Engineering

Master Engineers and Designers, Inc.

-----Original Message-----
From: Andrew Kester, P.E. [mailto:akester(--nospam--at)]
: Monday, February 04, 2008 9:31 AM
To: seaint
Subject: re: retrofit existing roof



Whether the Code in your jurisdiction says it or not, you are buying that roof. If there are any problems with that roof throughout his life, you are on the hook. Make sure the old roof can handle all the loads that are on it once you are all done with it, at least you are not in snow country, but you do have wind and seismic connection issues.


If there is a section in your code on Existing Structures (there is one for us in FL in the FBC), they may require lateral force system upgrades. There are many situations now where if you modify the roof system you must upgrade the entire lateral system to conform to current wind and gravity load requirements. We always inform the owner of this during our proposal phase, so they understand the costs involved.



Andrew Kester, P.E.
Principal/Project Manager
ADK Structural Engineering, PLLC
1510 E. Colonial Ave., Suite 301
Orlando, FL 32803