Information & Commentary by Brian Abney
What Is Underneath?
I'm frequently asked about installing a new roof as a Retrofit (roofing over an existing roof) versus taking the additional steps to tear-off the existing roof prior to new application.
Firstly, there are many times that a retrofit roof is the best roofing solution. But too many times building managers simply look at the costs savings as the deciding factor. The most important question to ask yourself when considering this decision is:
"What is underneath?"
Sure a retrofit roof system may stop a leak, but what is the condition of the other materials that the leak has affected.
Roofing over wet insulation can cause:
- Mold and Mildew
- Corrosion of Fasteners
- Rusting of the Deck
- Loss of R Value
- Freeze / Thaw
The long term effects of roofing over wet insulation can far out-weigh any cost savings. My advice is to have a professional roof contractor perform a detailed core analysis of the roof. A visual inspection and infrared inspection can determine the condition of the core roof system. In my experience, building managers should ALWAYS have an upfront diagnostic of the roof system before making a decision. Once, it is determined "what is underneath", a more educated decision can be made as to whether or not the retrofit roof is the best solution.