Do solar panels cause roof leaks?

For most people, their home is their biggest financial asset. Drilling holes into it might seem like a bad idea, but that’s usually what’s needed to install solar panels on a roof.

And yet, this does not need to be cause for concern: there are millions of homes with solar panels around the United States, and the majority of them are problem-free.

Solar panels do not need to cause roof leaks: they can last problem-free for 25 years or more. But unfortuately every industry has bad practitioners, and solar isn’t immune to this problem. Shoddy installations can happen, even years after the initial installation. You might not even notice that the roof sheathing has been damaged until the problem is severe.

Fortunately, there are steps you can take to prevent this. If you’re thinking about installing solar and you’re concerned about what that means for your roof, read on to learn more.

Shoddy installation practices can mean leaky roofs and expensive repairs

It’s not hard to find examples of disgruntled solar homeowners dealing with leaky roofs even years after the installation was done.

Telsa customer dealing with leaky roof for two months with no help

A Tesla solar panel installation can be the cheapest in the industry, but poor customer service is a common complaint. One exasperated Telsa customer took to their discussion forums in search of a solution:

My solar panels were installed in November 2020. When the rains came in late December / early January I had water running through the light fixtures on my kitchen ceiling, and the hall ceiling. Tesla came out to do an emergency roof repair on 4th January 2021. Turns out that the installers had drilled many exploratory holes in the roof, but had neglected to fill some of them. The guy did a temporary repair in the rain, but said they would have to come back on a dry day to do the permanent repair... My roof has now been leaking for two months, and no end in sight.

While Telsa’s low price is attractive, like many large companies they employ or contract with installers all over the country, making it difficult to maintain good quality control.

Installation problems and a leaky roof in Texas

It’s not just large national companies that have this problem - smaller local companies do too. Here’s a BBB complaint about one company in Texas:

Kosmos Solar installed solar panels on our roof, but had roof leaks in bedroom and kitchen. They DID NOT complete the repairs...The most current roof leak repair is outstanding since 09/29/2020. Not at all happy with Komos Solar cause I was informed that one of their installers drilled several holes in our roof that completely missed the roof rafters that caused the roof leak.

What this customer described is a common problem for inexperienced solar installers. When attaching the solar racking system to a roof, the bolts need to be drilled into the rafters (the thick beams that form the structure of the roof) to make a secure connection. From the top of the roof, it can be hard to know where the rafters are.

Fortunately for this customer, Kosmos Solar did repair the issue, but it involved months of inconvenience.

Sunrun customer with leaky roof and interior damage, waiting a year for a fix

Sunrun is the largest rooftop solar installer in the country. Given their huge scale, it’s no surprise that you can find around 800 complaints on BBB in the past 3 years alone.

It’s not hard to find complaints about roof leaks, like this customer in Grand Prairie, Texas:

Solar panels improperly installed in December 2018 - caused leaks that have not been repaired as of January 2020. Ruined roof & interior damage. Damaged roof needs to be replaced - both decking AND shingles...They sent an inspector at that time who stated that the damage was done by improper installation, and they would fix the issues at no cost to us. We repeatedly called and emailed, and they kept promising, but never followed through. Finally, the panels were removed December 19, 2019, and now we have more leaks while waiting for their roofer to make repairs.

Sunrun never responded to this BBB complaint, so we don’t know if this customer finally had their problem resolved. Either way, more than than a year of dealing with a roof leak is a nightmare scenario.

How are solar panels attached to a roof?

Solar panels for home use are roughly 39 inches by 64 inches, give or take a couple inches. The average home system might have a couple dozen panels or so.

All of those panels are bolted into a specialized rack made of aluminium. In turn, the rack is attached to the building with footings. Altogether, the system can weigh hundreds or thousands of pounds, so these footings have a critical job.

There are many manufacturers that make solar racking products, and they all have different designs to prevent leaks over the 25 year lifespan of the system.

Most use flashing, which is a flat sheet of aluminium that acts as a shield over the drill hole. Here’s an example from the company Unirac:

The main concerns are 1) hitting the rafter with the bolt and not just the thin plywood sheathing and 2) sealing the hole in the roof according to the manufacturer’s directions.

Typically a sealant is applied to the hole such as silicon, rubber, or butyl tape. (The type will depend on the roofing material.)

However, a well-designed footing doesn’t rely on the sealant as the primary waterproof barrier. They can dry and lose their effectiveness over time, so they are really only a backup in a good system.

It’s the design of the footing that provides the primary waterproof barrier in most systems. Aluminium doesn’t rust, so as long as it’s installed correctly, the system will keep your head dry for decades.

Tile roofs and roof leaks

Tile roofs, especially clay tile, are the most complicated type of roof on which you can install solar panels. In fact, many solar installers will refuse to install solar on a clay roof. The tiles are simply too brittle.

That said, there are solar racking systems designed to work with tile roofs.

The topic is complicated enough that we have a separate article on installing solar on tile roofs.

Metal roofs and solar are a great combo

On the other side of the side of the spectrum are metal roofs. While not quite indestructible, metal roofs can last a very long time - 50 years or more.

As an added benefit, installing solar panels on a metal roof might not even require any holes. If you have a standing seam roof, solar panels can be attached without any holes at all. The racking system clamps to the seam.

As with tile, metal roofing is unique enough that we have a separate article about it.

A good installer warranty is important, but not an absolute guarantee

So as a solar customer, what can you do to protect yourself?

First of all, the installer’s warranty is very important. Be sure to read the contract to understand what it covers, but a good company will include roof leaks as part of their warranty.

The duration of the warranty will vary. You should expect at least five years, but great companies will offer a much longer duration. Some of the best companies in the Solar Nerd network offer a 25 year warranty.

However, a warranty is only as good as the customer service the company provides. If they never pick up the phone as the Tesla customer above complained about, the warranty isn’t going to be much help and you may need to resort to other measures, such as small claims court.

Don’t install solar panels on an old roof

But perhaps the most important way to protect yourself is in your hands, which is to not install solar panels on an old roof.

Personally, I would only get solar panels if I had at least 15 years of life left on my roof. That’s enough for you to earn back your solar investment if you have a sunny roof.

A really old roof might not be structurally sound enough for solar panels, no matter how good a job the installer does. Unfortunately, some unscrupulous companies only care about the sale and will install solar panels even if your roof is too old.

To protect yourself, screen out lousy solar installers

There’s no guarantee that you won’t have problems with your solar installation, and even the best companies make mistakes. However, good companies will make things right, unlike the examples above.

There are simple things that a consumer can do to protect themselves. For one, many states allow you to check a company’s contractor license online and see if they have any complaints on record. If you find a complaint, think twice about hiring that company.

As an example, Tesla Energy has numerous citations in California for issues such as departing from trade standards and not having permits for a project. Any company with a record like that is excluded from The Solar Nerd network.

There are several other things you can do to identify great solar installation companies, which are described in our article on finding a good local solar installer.