Reroofing under solar: panel removal and reinstall in Vancouver, WA

Solar arrays usually outlast the shingles they were set on. Panels often go onto a roof that is already ten or fifteen years old, and a decade later the shingles under them are worn out while the panels still produce power. At that point the array has to come off so we can tear off, replace decking where needed, and lay new underlayment and shingles across the whole slope.

Our crews handle the roofing side of the job: unbolting panels from the racking, removing rails and mounts, storing everything on site, flashing new attachment points into the new roof and setting the array back. The electrical disconnect and reconnect is handled by a solar or electrical pro where it is required, and we schedule around them. If your system is leased, we also coordinate with the company that owns it.

Why the panels have to come off

Shingles under a solar array cannot be replaced in strips. The racking is bolted through the roof into the rafters at many points, and each of those points has its own flashing that has to be lapped into the shingle courses above and below it. Trying to slide new shingles under the rails leaves the old mounts sealed into old material, which is exactly where leaks start a few winters later.

Leaving the old roof in place under the panels is not a good bet either. Shaded shingles under an array stay damp longer in our climate, and moss, needles and nesting material collect in the gap between panel and roof. When we take arrays off, we often find soft decking at the upper mounts and debris packed against the lowest rail, all of which is easier to fix with the panels set aside.

Who does what on a solar reroof

This job involves more parties than a normal reroof, so we set the order of work before anything comes off. Our roofers do the mechanical work on the roof itself. Anything that touches the inverter, wiring or utility connection belongs to a solar or electrical pro, and leased systems may have their own rules on who can handle the panels. We call those parties before we book your dates.

• Solar or electrical pro shuts down and disconnects the system where required
• Our crew removes panels, rails and mounts and stores them on site
• We tear off, repair decking and install the new roof
• New mounts are set into rafters and flashed into the new shingles
• Our crew resets rails and panels in their original layout
• Solar or electrical pro reconnects and tests the system

Mounts, flashing and keeping the roof watertight

The weak point on any solar roof is where the attachments go through. On a new roof we locate rafters again rather than reusing old holes, seal the abandoned holes in the decking, and install flashed mounts that sit under the shingle course above, so water runs over the flashing instead of against a bead of sealant. Sealant alone dries out and cracks after a few of our wet winters.

We also look at how the array will sit on the new roof. Rail height affects how easily needles and leaves wash out from underneath. Some owners add critter guard mesh around the edge of the array while it is off, to keep birds and squirrels from nesting under the panels. Wire runs get secured off the roof surface so they do not rub through the new shingles.

Planning ahead if your roof is aging

If you are thinking about adding solar and your roof is more than about twelve years old, replacing the roof first usually costs less overall than paying for removal and reinstall later. If panels are already on, plan the reroof before leaks start, not after. A slow leak at a mount can rot the decking for a full season before a stain shows on the ceiling, and that turns a planned job into a rushed one.