The deck on a mill is steel, concrete plank, or board on heavy timber. The purlins are what a rail or a ballast tray has to meet. A Woonsocket Rhode Island solar permit that arrives with a residential rafter table is describing a house. This building is not a house. The table will not show the deck, the purlin direction, or the ballast zones a mill roof actually has.
A mill roof is not a house template
A residential permit template assumes repetitive wood rafters, a shingle or asphalt roof, and an attachment schedule written for that repetition. A mill does not offer you that repetition. One wing may be steel deck on bar joists. Another may be a concrete plank. A third may be a later addition with a different deck and a step in height between them. One rafter table copied onto all three wings is three wrong roofs.
Start with the deck the installer measured, not with the deck the template prefers. Concrete plank, steel deck, and board-on-timber do not share a fastener. If the field notes say the covering is a membrane over something the installer could not see, say that on the sheet and stop the attachment callout until the deck is known. Guessing a screw into an unknown deck is not a structural plan.
Purlins need a direction and a role. Show which way they run. Show whether the foot, the clamp, or the tray lands on a purlin, or whether the design is asking the deck to span between purlins. If the installer has not measured that spacing, the sheet is not ready. Do not drop in a spacing you hope is typical. A number you invented will not match the bay the crew finds on install day.
What the structural sheets have to show
Draw the load path in the plan, not in a slogan. Module to clamp or ballast block. Block or clamp to rail or tray. Rail or tray to purlin or deck. Deck or purlin to beam. Beam to column or bearing wall. If any link in that chain says "existing, assumed adequate," the sheet is not ready to leave the office. The mill has been standing for a long time. That is not the same sentence as "this roof can take this array in this layout."
Ballast zones are part of that path when the roof is not penetrated. Edge, corner, and field do not get the same treatment, and a mill rarely has one simple rectangle. A parapet on one side, an open edge on another, and a lower roof where a later building was tied on: each one resets the zone. A note that says "ballast as required" is not a layout. Show where the blocks go and which roof plane they belong to.
Monitors, the raised clerestory bays on these roofs, split the array into separate planes. Draw each plane. Do not drape one module grid across a step you have not detailed. Show the drains, the clear space the installer marked, and the roof hatch. A module that covers the hatch will fail a walk-through even when the one-line is clean. If a row only exists because the sketch ignored a stack or a patched vent, delete the row. The module count on the roof plan has to match the one-line.
The Woonsocket Rhode Island solar permit is its own filing
The municipal building permit and the Rhode Island Energy interconnection application are separate submissions. The city does not forward your structural set to the utility because you asked it to. The utility does not review purlin direction because the one-line is complete. Same equipment list, different covers, different questions.
Give the city the roof framing, the attachment or ballast layout, and the electrical sheets. Give Rhode Island Energy the interconnection package that matches those equipment counts. Do not write "see building permit" on the utility one-line and stop. Do not write "utility will review structure" on the city set. The Rhode Island Energy interconnection is the utility half. The city half is the permit set.
This post does not name a Woonsocket fee, a portal, or a historic-district map. Those are city facts, and they are not in the drawing. The installer confirms the fee, the way the city wants the application, and whether this mill sits in a district that adds a review. If a district letter or a planning condition exists, it goes in the submittal. The designer does not invent a board name to fill a cover sheet.
Prepare engineered framing for a PE seal
Structural sheets for a non-residential roof should be prepared for a PE seal when the framing is engineered. Engineered framing here means the roof was designed as a structural system: steel beams, open-web joists, heavy timber, concrete. That is the mill. It is not a one- and two-family rafter roof, and it should not be drawn as one.
No Woonsocket rule on the desk starts the seal at a given array size. When the framing is engineered, have the structural sheets ready for a Rhode Island PE. Ask the building official what that office wants sealed, and do not borrow a house-job rule of thumb.
The sheets that usually carry that seal are the roof framing plan, the attachment or ballast plan, and the calculation cover that states what the calculations include. The sales PDF does not get a seal. A production page is not a structural calculation. PE stamping belongs on the engineering sheets. Permit design is the set those sheets live in.
What has to be in hand before anyone draws
Ask the installer for the occupancy, not just the street address. A mill can hold manufacturing, storage, offices, or a mix. The roof plan should say what is under the array in plain language the installer confirmed. Photos of the deck edge, a purlin bay, the drains, the hatch, and any step between roofs are the source for the zones. A single drone shot of the whole block is not a framing survey.
Decide attach or ballast from the deck, not from the module count the proposal wanted. If penetrations are barred, draw the ballast zones. If the deck can take attachments, the fastener has to match that deck. Writing both "attach" and "ballast" on the same bay, with neither one located, is a sheet that is not finished. Show the access path from the field sketch. Do not borrow a house-template width and call it the mill's rule.
Who draws it, and who builds it
Athol prepares the permit drawings, and the structural seal when the framing calls for it, for installers working in Rhode Island. We are not the crew on the mill. The installer measures, pulls the municipal permit, meets the inspector, and builds the array. The Rhode Island design work and, where the roof is a commercial structure, the commercial drawing set should read as a mill: deck, purlins, zones, and a one-line that matches the module count.
If the set in front of you still has a rafter table and a single-family title, it is the wrong building. Replace those sheets before anyone files. The city package and the Rhode Island Energy package can then carry the same array, each with the cover that reviewer expects, and neither one pretending a house detail is a mill roof.