Do Solar Panels Need a Structural Review?
Yes — adding solar panels changes the loads on a roof, so most jurisdictions require a structural review or letter confirming the existing structure can carry the panels plus the wind and snow loads they will see.
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What the engineer checks
The added dead weight of panels and racking, increased wind uplift on the tilted array, and how the attachment points transfer those loads into the existing framing. The review compares the new demands against the roof's original design capacity — most modern roofs have margin, but the engineer has to prove it.
Older roofs need more scrutiny
Aging structures, previous reroofs (extra layers add weight), signs of distress, or construction that predates modern codes all raise the stakes. Sometimes the answer is reinforcement — sistering rafters, adding blocking — before the array goes up. Finding that out before installation beats finding it out after.
Commercial and ballasted systems
Flat commercial roofs often use ballasted (weighted, non-penetrating) arrays, which add significant dead load with no uplift benefit. These almost always need a full structural analysis, and the roof warranty implications need to be settled with the manufacturer too.
The bottom line
Solar is a structural addition, not just an electrical one. A structural review is typically a quick, inexpensive letter — and it is what the permit office wants to see.