Your roof is getting replaced. The solar has to come off and go back on. So what actually keeps water out of all those holes in the new shingles? The answer is solar panel mount flashing, the small metal or membrane pieces that sit under the shingles at every bolt. Most homeowners never see them. They still decide whether the new roof stays dry for its whole life.
This guide walks through what the mounts do, why the flashing matters more than the panels when it comes to leaks, and what to ask before the array goes back up on a Crestwood roof.
Key takeaways
- Every solar mount is a hole in your roof, and flashing is what sheds water around that hole.
- A reroof is the natural time to replace mount flashing, because the shingles around it are new anyway.
- Good flashing is layered so water runs over it and down, like shingles do. Sealant alone is not a substitute.
- Old mount hardware and old flashing should not simply be bolted back into a brand-new roof.
- Roofing work in Crestwood is permitted work through the village, so coordinate the reset with your roofer’s permitted job.
- Ask who is responsible for the penetrations before anyone climbs a ladder.
What does a solar mount actually do on your roof?
A solar mount is the anchor that ties the racking to the structure of your house. Each one is usually lagged through the roof deck into a rafter, and the rails and panels hang from those anchors. A typical home array can sit on dozens of them.
That makes every mount two things at once. It is a structural connection that has to hold the array against wind and snow. It is also a deliberate hole through the shingles, the underlayment and the deck. The racking only stays put if the bolt bites into solid wood. The roof only stays dry if the hole is covered properly.
On a detach and reset, the panels and rails come off, and so do the mounts. Your roofer tears off down to the deck, replaces what needs replacing and puts down new underlayment and shingles. Then the mounts go back in, through brand-new material. How that step is done is the whole story of this article.
Why is flashing more important than the bolt?
Flashing is the piece that stops water from following the bolt into your attic. The bolt holds the array. The flashing protects the hole the bolt made.
The Department of Energy’s Building America Solution Center lists mounting brackets for solar panels right alongside vents, chimneys and skylights as roof penetrations that need proper flashing. Its guide to flashing penetrations on existing roofs says that whenever a new hole is cut in a roof for a solar bracket, proper flashing should be part of the job, and that water control materials should be installed in shingle fashion.
“Shingle fashion” is the key idea. Water runs downhill. A good flashing tucks under the shingle course above it and lies over the course below it, so rain sheds across the top instead of getting behind it. A blob of caulk around a bolt might look sealed on the day it goes in. Sun, cold and roof movement work on it every season after that.
What goes wrong when old mounts go back into a new roof?
Reusing tired hardware is the most common shortcut, and it undercuts the money you just spent on the roof. A few specific problems show up:
The flashing no longer fits the new shingles
Flashing is sized and seated for the shingle layout around it. New shingles land in new courses. A flashing pulled off the old roof may not line up with the new exposure, which means it may not tuck properly under the course above.
The seal surfaces are worn out
Mount hardware often uses gaskets or sealing washers. Those have been compressed for years. Once a fitting is backed out, it is not the same part it was on install day.
The bolt lands in an old hole
If a lag goes back into the exact hole it came out of, it may not grip the rafter the way it should. Mounts belong in sound wood. If the deck was replaced, the rafter layout under it still has to be found and hit.
Nobody owns the penetrations
This one is not about hardware at all. The roofer says the solar company handles the mounts. The solar side assumes the roofer flashes them. A leak at a mount then turns into an argument. Settle it before the tear-off.
How should mounts and flashing be handled on a reset?
The short version: new flashing at every penetration, mounts set into solid structure, and everything layered with the new shingles. Here is how that looks in practice.
- Map the array before it comes off. Photos and a layout sketch record where each mount sat and how the rails ran. That record speeds up the reset and keeps the array square.
- Pull the mounts with the panels. Old mounts come out so the roofer gets a clean deck with no hardware sticking up.
- Let the roofer finish the roof. The new underlayment and shingles go down across the whole area first.
- Locate the rafters again. Mount positions are marked off the framing, not off the old holes.
- Install mounts with fresh flashing. Each flashing slides under the course above, and the mount is fastened through it into the rafter.
- Check every penetration before rails go on. Once panels are back, the mounts are hidden. This is the last easy look.
That sequence is exactly what a solar detach and reset is built around. Electrical shutdown, removal, labeled storage and the production test matter too, but the re-flashed mounts are what your new roof has to live with.
Does Crestwood treat this as permitted work?
Yes, at least on the roofing side. The Village of Crestwood’s Building Department page lists re-shingling roofs among the work that requires a permit, along with electrical work. It also states that all contractors must be registered with the village.
That matters for the solar side in a practical way. The mounts go back through a roof that was just built under a permit, so the reset should fit that same job instead of happening as an afterthought. Rules can change, so confirm with the building department what your specific project needs, including whether the electrical reconnection calls for its own permit or inspection. The same goes for homes in Alsip, Midlothian or Oak Forest, where each village runs its own permit desk.
Why is a Chicago-area roof hard on mounts?
A roof here gets every kind of stress a mount can face. Winters bring snow that sits on the array and cycles of thawing and icing that push water into any gap that is not layered correctly. Spring storms bring wind-driven rain that does not always fall straight down. Summer heat bakes sealants on dark shingles.
None of that is unusual for homes along Cicero Avenue or anywhere else in the south suburbs. It simply means a mount detail that might get away with sloppy work in a mild climate gets tested hard here, year after year. Flashing that sheds water by its shape, not by caulk alone, holds up better to that cycle.
Is this the right time to rethink your roof and solar plan?
Often, yes. The Department of Energy’s homeowner’s guide to going solar tells homeowners to consider the age of their roof and how long until it will need replacement. If you are already replacing the roof, you have handled the biggest timing question. The array goes back on a fresh roof that should outlast the panels’ remaining years, rather than an old roof that would force another removal later.
If your roof is near the end of its life but the tear-off is not booked yet, plan the two jobs together. A roof replacement under solar panels works well as one coordinated plan: detach, reroof, reset, with nobody waiting on anybody.
Before the first bolt comes out
Ask one question before you sign anything: who installs the new flashing at each mount, and who stands behind those penetrations afterward? Get the answer in writing on the quote. Then ask whether the mounts are being reused or replaced, and how the crew will find the rafters on the new deck.
If the answers are vague, slow down. A clean reroof with a sloppy reset is still a leaky roof. If the answers are clear, you are in good shape.
When you are lining up the panels and the reroof together, our detach and reset service covers the mounts and flashing as part of the job, and Solar Panel Removal Crestwood is happy to compare notes with your roofer on the plan. You can also browse the rest of the site from the homepage.