Retrofits for aging metal roofs

By Jesse Sanchez. 

Exploring retrofit solutions for extending the life of metal roofs and ensuring structural compliance.  

In Comparison of Retrofit Systems Over Existing Metal Roofs, Brian Gardiner from BMG Enterprises, LLC offers a thorough independent 3rd party analysis of retrofitting options for aging metal roofs, focusing on the choice between metal-over-metal and single-ply membrane retrofits. As older metal roofs approach the end of their lifespan, Brian notes that retrofitting “has many advantages over reroofing,” such as using the old metal roof for “temporary building interior protection during new roof installation,” allowing for continued building operations and reducing environmental impact by minimizing landfill waste. 

Brian advocates for lightweight retrofit systems, typically under three pounds per square foot, to avoid adding undue stress on the existing structure, which is often not designed to support additional heavy loads. Both metal-over-metal and single-ply retrofits achieve this, but with distinct structural considerations. For instance, Brian notes, metal-over-metal retrofits “do not typically rely on the existing metal roof to function as a structural deck for support and attachment of the new metal roof system.” In contrast, single-ply systems depend on the underlying, often compromised old metal roof, to   serve as “support of live, snow and wind loads and for providing stability to the roof support members.” 

Navigating building code requirements is also essential, as the International Building Code (IBC) and International Existing Building Code (IEBC) lay out structural mandates to ensure any added weight or modified structure meets modern standards. Brian recommends consulting with licensed engineers who understand these codes to handle critical considerations like load paths, fastening, ponding and drag load resistance. 

Brian offers valuable and practical guidance for industry professionals seeking retrofit solutions that effectively extend the lifespan of aging metal roofs while meeting today’s stringent safety, environmental and performance standards. 

Learn more about retrofit solutions and extending the life of your metal roof with RoofHugger!