Roof leaks after solar installation: liability and remedy

What the code actually requires

Start with the code, because it is more specific than the folklore and it is checkable against your own installation.

Solar penetrations get no special rule. The residential code provision on roof penetrations for photovoltaic systems reads: "Roof penetrations shall be flashed and sealed in accordance with Chapter 9." Chapter 9 is the ordinary roof-assembly chapter. A solar mount is held to the same flashing standard as any other hole in your roof.

That chapter is specific about where and what. Flashings must be installed "wherever there is a change in roof slope or direction and around roof openings", and where flashing is metal it "shall be corrosion resistant with a thickness of not less than 0.019 inch", which the code identifies as No. 26 galvanized sheet. That is a checkable material minimum rather than a general instruction.

The manufacturer's instructions are part of the code. The photovoltaic provision requires that systems "shall be designed and installed in accordance with Sections R324.3.1 through R324.7.1 and the manufacturer's installation instructions". Read that carefully: departing from the racking manufacturer's instructions is not merely a warranty problem, it is a failure to meet the code.

And everything exposed must resist corrosion. "All components of the photovoltaic solar energy system exposed to the weather shall be constructed of approved corrosion-resistant materials." That reaches flashings and fasteners, which is where a slow failure usually begins.

Two further provisions govern placement: attachments are required to go into framing rather than sheathing alone, at a specified maximum spacing that tightens near roof edges, and penetrations are prohibited within a set distance of a valley's low point, which is the part of a roof carrying the most water.

The finding that changes the usual advice

The received wisdom is that putting solar on your roof voids your roofing warranty. We read a major shingle manufacturer's limited warranty in full to check, and what it says is different and more interesting.

The word "solar" does not appear in it. Nor does "penetration". Nor does "third party". Nor does "void". Not once, in any of the four cases.

What it says instead is close to the opposite of the folklore: "Even if your GAF Products were not properly installed according to GAF's application instructions or to standard good roofing practices, this limited warranty remains in effect."

Improper installation does not void that warranty. It stays in force. What it does is remove the resulting damage from cover, which is a narrower and more precise consequence than voiding, and it means a homeowner told "your roof warranty is gone" has been told something inaccurate.

But now the part that actually matters, and it is worse than the folklore rather than better. The same warranty excludes from coverage "costs related to underlayments (unless your claim involves a manufacturing defect in a GAF Underlayment), metal work, and flashings".

Flashing is excluded. Outright. And flashing is precisely the component a solar mount penetrates and depends on. So the roofing manufacturer never covered the thing your solar installation put a hole through, before anybody installed anything.

Why the leak is rarely where the stain is

One practical thing is worth knowing before the argument starts, because it determines whether anyone finds the problem at all.

Water does not fall straight down through a roof. It enters at a penetration, runs along the underside of the decking, follows a rafter, and appears at whatever low point it reaches. A stain on a bedroom ceiling can originate several feet uphill and to one side. That is ordinary building physics rather than anything specific to solar.

The consequence is that "there is no leak above the stain" is not a finding. It is where an inadequate inspection stops. A serious diagnosis traces the path rather than looking directly overhead, and it usually means someone in the roof space with a torch while water is applied above.

It also means intermittent leaks are normal rather than suspicious. A penetration that only fails under wind-driven rain from one direction, or only once snow has built up and started melting under the array, will pass a dry inspection every time. If yours only appears in certain conditions, that is information about the failure rather than doubt about whether it exists.

Ask for the inspection method, not just the conclusion. Whether anyone went into the roof space, whether water was applied, and which mounts were checked. A report that says the roof was inspected from the ground, or from a ladder at the eaves, has not looked at the thing in question.

Preventing it, which is the only part fully in your control

Everything above is remedy. The prevention is short, and it happens before installation rather than after.

Ask the age and condition of the roof, honestly, and re-roof first if it is close. Removing and reinstalling an array to replace a roof underneath is substantial work that no warranty covers, because it is not a defect. A national laboratory's own guidance on this notes that re-roofing is a decommissioning trigger, with "many owners finding it more cost-effective to remove the older system and install a new one rather than reinstall the old equipment", and adds that "many contractors also refuse to offer or warrant reinstallation of old equipment".

Get the roof penetrations named as covered in the workmanship warranty, in those words. Not covered by implication under a general term. Ambiguity in that sentence is resolved years later, with water already inside.

Ask who is doing the flashing and what they are flashing with. If a licensed roofer inspects or certifies the penetrations, you have a second party with a stake in the waterproofing. If the solar crew does it alone and nobody else looks, every roof risk you have is concentrated in the one warranty with no backstop.

And keep the racking manufacturer's installation instructions. They are part of the code requirement, they are usually available online, and they are the document against which "was this done properly" is actually answerable.