Comp roof life under PV panels
Clients have asked this and I never have a real confident answer so I’d love some more official opinions. Or point me to an existing article/Q&A, I wasn’t able to find one.
When installing a PV array on an existing comp shingle (or ashpalt) roof, how does the array affect the longevity of the roofing underneath?
I know that the panels will tend to protect the roofing therefore extending it’s life, but here in the Northwest it seems it might also encourage moss growth on the shingles. And either way it will someday need replacing which is definitely complicated by the array.
Can we say the array will make the roofing last longer? Or is it a wash?
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The array will protect whatever roofing is under it from UV exposure, which means it won't fade as much and will probably last a little longer. The issue is you'll have a bunch of roof penetrations for the array supports, and regardless of how these are done, they're weak spots. I would say that the solar array will protect the roof in some ways, but cause new issues in other ways, and I wouldn't count on the array to make the roof last longer overall.