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 a letter confirming the existing structure can carry the panels plus the wind and snow loads they will see. The panels themselves are light. That is not the whole story. The array adds dead weight, catches wind like a set of shallow sails, concentrates loads at attachment points, and stays up there for decades through every storm the site will see. Torch Engineering PLLC treats a solar review as a real structural check, done fast: verify the framing, the attachments, and the load path, and give the permit office a letter a reviewer can rely on.
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What the engineer checks
The review covers 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 engineer compares the new demands against the roof's original design capacity. Most modern roofs have margin, but the engineer has to prove it, with the actual rafter or truss sizes, spans, and spacing from your roof, not a generic assumption. Bring whatever you have: the solar layout, panel and racking specifications, roof age, and any prior plans or truss documents. Attic access that lets the engineer or installer verify framing size and condition saves a second trip and removes the largest unknown in the review. A letter built on verified framing clears review. A letter built on guesses invites questions.
Older roofs need more scrutiny
Aging structures, previous reroofs with extra layers adding weight, signs of distress, or construction that predates modern codes all raise the stakes. Sometimes the answer is reinforcement — sistering rafters or adding blocking — before the array goes up. Finding that out before installation beats finding it out after, when panels must come off to fix framing that should have been strengthened first. Sagging ridges, cracked drywall ceilings below, water-stained decking, or a roof that has been re-covered multiple times are all facts to disclose at the start. A competent review accounts for reduced capacity honestly and designs the fix while the roof is still open and accessible. Solar installed over a weak roof does not make the roof stronger. It makes the eventual repair far more disruptive.
Commercial and ballasted systems
Flat commercial roofs often use ballasted arrays — weighted, non-penetrating systems held down by their own mass. These add significant dead load with no uplift benefit from attachments, and the weight concentrates where trays and ballast blocks sit. Ballasted systems almost always need a full structural analysis, checking the deck, joists, and supporting structure under the loaded zones, plus wind behavior of the array itself. The roof warranty implications need to be settled with the manufacturer too, because added loads, foot traffic patterns, and ponding changes can all affect coverage. Owners should also confirm the roof's remaining service life before covering it with an array expected to serve for decades. Re-roofing under an installed array means removing and reinstalling the system, and that cost belongs in the decision before the first panel lands.
Attachments, uplift, and the load path
On pitched roofs, each attachment is a point where uplift tries to pull the array off and where water tries to get in. The review checks attachment spacing against wind demands, lag or fastener embedment into framing rather than decking alone, and flashing details that keep the roof weather-tight. Missing a rafter with an attachment is not a cosmetic error; it removes that point from the load path and overloads its neighbors. Installers should work from a layout that shows framing locations, not just panel geometry. In higher wind regions and on taller or more exposed buildings, uplift demands grow quickly and attachment schedules tighten accordingly. The structural letter should state the governing wind assumptions plainly, so the reviewer sees the design was done for your site, not copied from a calmer one.
What speeds the review up
A complete information package is the difference between a quick letter and a slow one. Provide the panel layout with setbacks, the racking manufacturer's specifications and span tables, panel weight, roof framing information, and photographs of the attic framing and roof condition where accessible. Flag known issues honestly: prior leaks, added roof layers, skylights or equipment in the array area, and any planned re-roofing. Torch scopes the review from that package, verifies capacity against wind and snow demands for the specific site, and issues the stamped letter with PE stamps backed by Apex Grid Engineering and licensed PEs in 49 states. If reinforcement is needed, we detail it in buildable terms your roofer or framer can price and install without interpretation. Fast here does not mean casual. It means complete inputs, one careful check, and no return trips.
Ground mounts and special cases
Not every array sits on a roof. Ground-mounted systems trade roof questions for foundation questions: posts or footings sized for soil conditions, frost depth where it applies, and uplift and lateral loads carried into the ground. Carport and canopy arrays are structures in their own right, with columns, footings, and vehicle clearance and impact considerations. Additions to older homes, roofs with engineered trusses that cannot be cut or modified casually, and properties in high snow or high wind zones all deserve the same careful treatment as commercial work. Tell the engineer the full mounting story at the start. The review that matches the real installation is the one that protects the owner, satisfies the reviewer, and still holds up when an insurer or buyer asks for it years later.
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.
Torch Engineering PLLC · (480) 490-0064 · info@torchengineering.com — PE stamping backed by Apex Grid Engineering.