What is a solar structural letter?

It is a sealed statement that the existing roof structure can support the named array and attachment, for the wind and the module layout on the permit. It is not a full house framing set.

Do you also stamp the electrical plans?

Yes, when the jurisdiction or the utility wants an electrical PE on the one-line and the interconnection. Ask for both at intake if the permit includes them. The solar PV page covers that scope.

What if the roof is too light for the array?

The letter is not sealed on a roof that does not work. The engineer tells you what has to change, and reinforcement can be added to the scope before anything is stamped.

How much does a structural letter cost?

A letter without reinforcement is a few pages at $100 per sheet. The live quote uses your page count. Final pricing is confirmed after the attic photos or truss sheets are reviewed.

Project types / Solar structural letters

A structural letter for the roof under a solar array

Many building departments accept a structural letter, instead of a full framing set, for a flush-mounted rooftop array. AllPEStamp reviews the existing roof and the racking attachment, then seals that letter with a professional engineer licensed in the project state.

Roof capacity for the array weight and wind
Racking attachment and spacing checked
Letter format many PV permits accept
Electrical interconnection quoted separately when it needs its own seal

Get a PE stamp quote

When a letter is enough

A flush array on a conventional roof is the usual letter. The engineer checks that the rafters or trusses can carry the added dead load and the wind on the modules, and that the attachment spacing matches the racking evaluation for that wind speed. Ground mounts, carports, and arrays that require new framing are plan sets, not letters.

The electrical one-line, the interconnection, and any service upgrade are a different seal when the permit or the utility asks for an electrical PE. Those can be quoted with the letter so the PV package stays in one place.

What to send with the roof

Upload the module layout, the racking cut sheet, photos of the attic framing or the truss specification, and the site address. Roof age and the span of the rafters are the two facts that decide whether the letter can be written or the roof has to be reinforced first.

If a previous letter was rejected, include the comment. The usual problems are the wrong wind speed, an attachment that does not match the layout, or a truss that was never identified.

Seal and price

The letter and any framing sketch that belongs with it are sealed. A letter is a small page count, so it prices at $100 per sheet unless it is bundled with the electrical set. Reinforcement details add sheets and are quoted before they are drawn.

Smaller letters can be done in about one business day. Standard turnaround is about three business days. Final pricing is confirmed after the roof photos are reviewed, because a roof that needs sistered rafters is a different job than a letter.

Disciplines on this project

These are the seals this kind of permit usually asks for. The quote lists only the sheets you upload.

FAQ

What is a solar structural letter?: It is a sealed statement that the existing roof structure can support the named array and attachment, for the wind and the module layout on the permit. It is not a full house framing set.
Do you also stamp the electrical plans?: Yes, when the jurisdiction or the utility wants an electrical PE on the one-line and the interconnection. Ask for both at intake if the permit includes them. The solar PV page covers that scope.
What if the roof is too light for the array?: The letter is not sealed on a roof that does not work. The engineer tells you what has to change, and reinforcement can be added to the scope before anything is stamped.
How much does a structural letter cost?: A letter without reinforcement is a few pages at $100 per sheet. The live quote uses your page count. Final pricing is confirmed after the attic photos or truss sheets are reviewed.