Comparison of Retrofit Systems Over Existing Metal Roofs
From MBMA, A MCA Partner Association
This white paper, written by Brian Gardiner of BMG Enterprises, LLC, compares two commonly used methods of retrofitting exiting metal roofs, single-ply systems and metal panels, and illustrates important design considerations that apply. The design consideration include the existing support structure, secondary framing deflection, the existing metal roof properties, drainage, roof fastening, drag load, and fire rating. The paper also contains a brief review of the building code requirement.
The goal of this paper is to compare two commonly used methods of retrofitting existing metal roofs and illustrate important design considerations that frequently apply to candidate buildings. As this is a limited review, not all
considerations will apply and additional items not addressed, such as the potential for condensation, can prove important to evaluate for a successful retrofit.