Metal roofs typically have a lifespan of approximately 30-40 years, but once time runs out and/or a roof begins to falter, there are different methods available to extend that timeline, including:

  1. Repair – this approach would be appropriate if the roof is leaking or faltering in some way in just specific areas; a repair would be less invasive and isolated to specific locations on the roof
  • Reroof – this approach removes the existing roof and replaces it with a new one; it is very invasive, expensive, and disruptive to and possibly must halt ongoing operations
  • Retrofit – this approach – which we’ll cover in more detail below – installs a new roof over the existing, failing roof; it is cost effective, fast, and just as effective as a total reroof and much less invasive

Based on the options available, we want to dive a little deeper into retrofitting. We believe it is a far superior choice to a total reroof for a number of reasons, including:

  • The original roof provides temporary protection during new roof installation
  • Much less disruptive to ongoing operations – ensuring daily activities can continue unimpeded
  • Reduces landfill waste
  • Reuses existing insulation and possibly adds more insulation over existing roof
  • Provides a safer work surface than exposed existing secondary structural members
  • Reduced cost

Retrofit Options

When retrofitting an existing roof, you want to choose a lightweight solution to ensure you’re not overloading the existing structure with a bulky new roof. There are two common options when retrofitting a faulty roof – metal over metal and single-ply over metal.

  • Metal Over Metal – Another light-weight metal roof is installed directly over the existing metal roof; this option does typically rely on the existing metal roof to function as a structural deck for support and attachment of the new metal roof system.  
  • Single-ply Over Metal – Many single-ply membrane roofs rely on the existing metal roof to function as a structural deck for support and attachment of the roof system, including board insulation, as well as for support of snow, and wind loads, and for providing stability to the roof support members.

Based on our experience and knowledge of the effectiveness of each option, we always recommend using Metal Over Metal. While using a single-ply membranes is acceptable and can be done, there are increased risks that come with this option. Pre-Engineered buildings are not designed for a single-ply membrane roof system. Metal roofs on a pre-engineered metal building are secured differently than single-ply membranes, so trying to marry the two systems together when covering the old roof with a new one, is very tricky and potentially disastrous.

There are several building code requirements, design considerations, and construction processes that need to be addressed based on either of these choices. But, to delve into all those details would entail a lot of technical and complex information that could support an entirely new blog post! Senate’s experienced and skilled staff can cover all the features and benefits of retrofitting your building’s roof. Just reach out to us today for more information!

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