Roofing a house with solar panels: a contractor's guide to detach and reset

Why you can't just slide a solar array up the slope and reroof under it

Sooner or later somebody floats the idea of sliding the array up the roof, tearing off underneath, and sliding it back down. It isn't a real option. The racking is lagged through the deck into rafters and the rails run across multiple shingle courses, so there is no version where you strip and dry in the deck beneath them. Moving modules means unbolting them from rails still anchored to the roof you're tearing off — at which point nothing is secured or watertight.

The hardware is the second problem. A residential module runs roughly 40 to 50 pounds and measures roughly six to six and a half feet by three to three and three-quarter feet, depending on vintage — manageable on the ground, awkward on a 7/12 in July. Glass cracks, backsheets tear, frames bend, and a discontinued module can be hard to match years later. That's not a shingle you swap at the end of the day; it's a claim against equipment that was never on your contract.

What's still energized on a solar roof during a tear-off

A solar module generates DC any time daylight hits it. There is no off switch on the panel. Opening the AC breaker stops the system pushing power into the house and the grid; it does not stop the modules producing. Tarping cuts the current, but voltage barely moves — a tarp blocking nine-tenths of the light still leaves nearly full voltage on the wiring. That isn't de-energizing, partial or otherwise. The roofing instinct — kill the breaker, get to work — is the instinct that gets somebody hurt on a PV roof.

Rapid shutdown is the piece most people half-remember. It first appeared in the 2014 NEC, but that edition only limited conductors well away from the array; the array itself stayed at full voltage. The requirement that conductors within a foot of the array drop to 80 volts within 30 seconds came in the 2017 NEC, effective January 2019, and that is the rule that forced module-level electronics. Pennsylvania did not adopt the 2017 NEC until February 14, 2022, so most PA residential arrays — including some only a few years old — were permitted with no array-level shutdown whatsoever and can carry several hundred volts DC across the roof plane. Rapid shutdown also has to be initiated, conductors inside the array boundary may sit at 80 volts rather than zero, and the provision exists for firefighters. It never makes an array safe to take apart.

Module-level equipment helps, but read it carefully. SolarEdge optimizers fall back to about one volt each when AC is removed. Enphase microinverters convert at the module, so no high-voltage DC string crosses the roof — but the trunk cable between modules is 240-volt AC and live any time the system is producing. Different hazard, not a smaller one, and on a battery system that AC can stay live even when the utility is out.

Pennsylvania has no statewide electrician license; requirements are set municipally, so scope and permitting vary township to township. One thing that doesn't vary: OSHA requires that only a qualified person work on or near energized electrical parts, and a PV array in daylight cannot be de-energized. That duty sits on you as the employer regardless of what your municipality licenses. Check your township's rules and your liability policy before a crew touches an array.

Detach and reset as a subcontracted service: what you're buying

As a subcontract, detach and reset for roof replacement is a two-visit job with your roof in the middle. On the first visit a solar crew shuts the system down per the manufacturer's procedure, disconnects and labels the wiring, pulls the modules, and removes rails and mounts down to the deck. Modules are stacked and protected on site or hauled off. You get a bare roof. After your work is done, the same crew sets new mounts, re-racks, remounts, rewires and brings the system back online.

Quoting practice varies, so ask before you build a number into your bid. Some companies price the reset by system size, per watt or per kilowatt — a shortcut that makes the bill scale with wattage rather than with the number of panels a crew actually has to carry, which works against a homeowner running fewer, higher-output modules. We quote on panel count, not wattage, as a flat project price put in writing after a free Solar Triage Call, a phone consult where we take the details and tell you what the job involves.

• A clean tear-off with no rails to work around and no live array in your crew's path.
• No responsibility for the shutdown, the re-commissioning, or the monitoring reconnect.
• One number for the homeowner's solar questions instead of your PM fielding them.
• Before-and-after photos of array condition — the record disputes come down to later.

Sequencing a reroof around detach and reset: who books first

The solar crew's calendar sets the roofer's, not the other way around. Book the detach first and build your tear-off behind it. That feels backwards if you're used to being the lead trade, but a roofing crew idle in the driveway because the panels are still up costs more than a week of patience up front. Ask the homeowner to let you coordinate both dates, and own the sequence — you're the one whose margin gets eaten when it slips.

The honest timing: most detach projects take about a day, and the reinstall typically one to two days depending on complexity. Your entire scope sits in between. The roof has to be finished and dry before reset, because new mounts and flashing get set into a completed roof rather than a partial dry-in. Leave a full day of daylight between your last shingle and the first mount.

Weather is where this gets expensive. A rain delay doesn't just move your crew; it moves a second crew already booked on someone else's roof, and the next opening may not be the next morning. The homeowner should understand before signing that the system is offline for the whole window and they're buying utility power meanwhile.

Ask early who handles permits and utility notification. Depending on the municipality, and on whether anything about the array changes, a reset may require a permit, and taking a system offline can involve notifying the utility to protect interconnection and net-metering status. That's the solar sub's lane, but it lives on your schedule.

Flashing and mount penetrations after a solar detach and reset

Reset means new mounts and new flashing set into the new roof, not old hardware dropped back through old holes. Flashed mounts get integrated into the water-shedding course, upper flange under the upslope shingles, so water runs onto the flashing and back onto intact roofing. A bead of sealant smeared over a lag is not a long-term water barrier — which is different from a listed self-flashing mount with integrated butyl carrying an ICC-ES evaluation, and those are legitimate. What you don't want is field-applied caulk doing the waterproofing on a roof carrying your name. Expect the new mount layout to chase rafters, so it may not land on the old hole pattern.

Every hole in that roof belongs to somebody. When the division is spelled out — your flashings, our mount flashings — a leak two months out has an obvious first phone call. When it isn't, you get a homeowner between two contractors, and whichever one picks up first tends to end up paying.

• Old lag holes closed and chewed-up decking repaired before dry-in — your scope, and it should be priced.
• New mounts flashed into the finished roof and integrated into the courses, not surface-sealed after.

Warranty lines on a solar reroof: roof system versus array

The clean split is straightforward. You own the roof system: deck, underlayment, shingles, your flashings, your workmanship warranty. The solar sub owns the array: modules, racking, wiring, the flashings under its own mounts, re-commissioning and reconnecting monitoring. Neither trade warrants the other's work. Put it in the scope documents both parties sign and give the homeowner a copy.

One more line to draw: your shingle manufacturer's warranty. GAF and Owens Corning both exclude the cost of removing an array so they can inspect or replace defective shingles, and enhanced system warranties can carry their own conditions where solar is involved. Read your manufacturer's solar technical bulletin before you write the scope, then tell the homeowner who pays if the array comes off for a shingle claim.

The failure mode all of this prevents is familiar. Two months later a panel stops producing or a ceiling stain shows up, and the homeowner calls whoever answers. Without a documented split you spend a Saturday proving a negative. With one, plus photos, the question tends to resolve in a phone call. That's cheap liability control on a solar reroof.

What to gather before you call a solar detach and reset sub

The fewer unknowns an estimator prices around, the tighter the number that comes back. Most of what a solar sub needs is a five-minute walk with a phone camera while you're on site for your own measure.

Some jobs will be orphaned systems: original installer out of business, homeowner locked out of the monitoring portal, no as-builts anywhere in the house. That doesn't stop the job. What it changes is discovery time, so it needs flagging before the quote rather than on reset morning.

• Panel count, plus a ground-level photo of each roof plane showing the full array.
• Pitch, stories, and access — driveway, landscaping, whether a lift can reach.
• Racking and rail type if there's a sticker; a close photo of one mount usually does it.
• Inverter brand and location: Enphase, SolarEdge, APsystems, or a central string inverter.
• Whether monitoring still works, and any contact for the original installer.

While the array is down: work you hand off instead of absorb

While the array is down, everything normally expensive to reach is sitting in the driveway: micro-inverter and optimizer replacement on equipment near end of life, a module that has underperformed for two years, critter guards on a roof with a squirrel problem, or monitoring that has been dark since the installer folded.

For you, that's revenue you hand off rather than absorb. Mention it to the homeowner, let the solar sub scope and quote it directly, and keep it out of your contract and off your workmanship warranty. You look like the contractor who thought ahead, and somebody else carries the equipment liability. We handle solar repair in Lancaster County and the eight counties around it.