PV system design

Do solar panels damage your roof? Let’s weigh the odds

One of the biggest fears of homeowners is that their roof won’t survive the installation of a solar panel system. Can solar panels damage your roof? Let’s break it down in this article.

Solar panels are safe for your roof but…

When a solar system is properly installed, a healthy roof is under no threat. There is a catch though – your roof should be “healthy” and your panels should be “properly installed”, and here’s why.

PV system may crush old or damaged roof

50 lb

average weight of a solar panel

Solar panels add a lot of weight to your roof. A residential solar panel is about 40-50 pounds per panel or 5-6 pounds per square foot. Commercial solar panels are even bigger and heavier – about 50-60 pounds. The weight of a system is typically well within a structurally sound roof’s capacity. But an already weak or aging roof may struggle to handle the additional load, leading to leaking, sagging, warping, or even collapsing.

While replacing or repairing a roof beforehand might seem like an additional upfront cost, it can save you money and headaches in the long run. Imagine a scenario where your roof fails a few years after solar panel installation. You’d have to remove the panels, replace the roof, and then reinstall the panels. Even if your old roof looks alright, don’t take a risk and call a roofing professional.

Vasilii Smirnov
Solar Installation Expert

A qualified roofing professional will assess the overall age and condition of your roof. They will look for signs of wear and tear, such as missing or damaged shingles, warped flashing, or signs of leaks. The inspector will evaluate the underlying structure of your roof, including rafters, trusses, and sheathing. This ensures your roof can safely support the additional weight of solar panels and their mounting systems.

DIY installation or inexperienced installers put your roof at risk

Even a healthy roof can get damaged if the solar panel installation is carried out incorrectly. Attempting a DIY installation or hiring an inexperienced contractor can lead to serious troubles.

In 2019, Walmart filed a multi-million dollar lawsuit against Tesla and requested to remove their panels from more than 240 Walmart stores. All because of the “negligent installation and maintenance” of solar panels resulted in seven fires and million-dollar losses over six years.

Solar panels require a secure mounting system that distributes the weight evenly across the roof structure. Improper installation can put undue stress on specific points, leading to cracks, punctures, and leaks. Most solar panel installations also involve roof penetrations to secure the mounting system. Poorly executed penetrations and inadequate flashing can create pathways for water infiltration, leading to leaks. Improper panel placement can also disrupt your roof’s natural ventilation, leading to moisture buildup, trapped heat, and accelerated deterioration of roofing materials.

Tatiana Ivanova
Author

Before you entrust your roof to a solar contractor, ensure the company is licensed in your state and employs certified solar installers. Look for companies with a proven track record and positive customer reviews. Qualified installers offer warranties on their work, providing peace of mind in case of any unforeseen issues.

If you’re considering a DIY attempt, gain a thorough understanding of the process. Look for instructional videos on YouTube by experienced installers, and supplement that with detailed articles to grasp each step involved, from safely setting up scaffolding to properly mounting the panels and securing the electrical wiring.

Some roof manufacturers may void your warranty if you install solar panels without their specific approval. Check with your roofer or the manufacturer before starting solar installation.

Roof type dictates installation method

The way you install the panels depends on what kind of roof you have. There are different installation techniques depending on your roof type to ensure a secure fit without harming it.

Metal roofs are the most solar-friendly

Installers love metal roofs: They are durable, reflect sunlight, which is good for bifacial solar panels and, of course, are easy to install panels on. The process of installing solar panels on a metal roof depends on what type you have: standing seam or corrugated one.

Metal roofs with standing seams are the easiest to install solar panels on. They need no drilling – you can attach the modules directly to the seams with special clamps. Corrugated roofs require more careful handling. The profile itself cannot support the mounting system, and you’ll need to fix the brackets with the screws. Most brackets are installed on the ridges, while some are to be fixed in the valleys.

Tile roofs are the most difficult for solar

Installing solar panels on a tile roof requires a more delicate touch. Tiles are fragile. They are not good at supporting extra weight and even a light pressure can break them. This job requires an experienced contractor, more time, and more money.

Some installers cut or even take off specific tiles to install special mounts for the solar panels. Others replace tiles in the solar panel installation area with composite ones and use conventional mounting systems.

Flat roofs are right in the middle

Flat roofs are an interesting case. They let you turn your panels to any side you want and customize their angle with mounts. But not every company warrants the panels installed on a flat roof and not every brand performs flat roof installations.

Solar panels for flat roofs can be mounted on a special tub or metal frame either weighted down with concrete blocks or screwed down to the roof. If you choose to screw your panels down, provide proper sealing, as flat roofs tend to pool rainwater. If you select concrete blocks, make sure the roof can support both the blocks and the panels.

Solar-paneled roof issues range from leaks to bird nests

While solar panels themselves pose no threat to the roof, they can create problems if not managed properly. Here’s how to address some of the most common concerns.

Improper solar installation creates pathways for rainwater

Leaks are homeowners’ worst nightmare. Improper installation can create gaps around the PV modules, allowing water to seep in and cause damage to your underlying roof structure.

Regular inspections are key to catching roof leaks under solar panels early on. Look for signs of water damage inside your home, such as stains on ceilings or walls. If you suspect a leak, don’t delay. Contact your solar installer or a qualified roofer immediately to identify the source of the leak and get it repaired.

Animals can damage both the wiring and panels

Birds and squirrels love to find cozy spots to nest, and the space under your solar panels can be an attractive option for them. The problem? Nests can trap debris, and block ventilation for panels. Animals can even damage the wiring, disabling some of your panels and raising the risk of fire.

To deter unwanted residents, you may install bird netting or deterrent strips along the bottom edge of the panels. Schedule regular inspections of your roof and solar panels to identify and remove any nests before they become a larger issue.

Bad ventilation causes mold

Solar panels can create a barrier that reduces airflow under the roof, potentially trapping heat and moisture. This can lead to problems like shingle deterioration and mold growth, especially in humid climates. This can silently eat away at the underlying roof structure and lead to significant damage if left unchecked.

4 inches

ideal air gap between solar panels and your roof

The key to prevent moisture buildup and protect your roof lies in proper ventilation beneath the solar panels. Many solar panel installations utilize a raised mounting system. This creates an air gap between the panels and the roof, allowing air to circulate freely and prevent moisture from becoming a problem.

Harsh weather can damage your roof and solar system

While severe weather itself won’t damage a properly installed solar system, problems arise from faulty installation. Strong winds or hail can exploit weaknesses caused by improper mounting or penetration points, leading to leaks or structural damage to the roof.

The best way to safeguard your roof against harsh weather is to ensure a professional and qualified solar panel installation. Look for installers who are certified by reputable organizations and have a proven track record of high-quality work with your particular roof type. Properly installed mounting systems can significantly reduce the risk of roof damage from solar panels. Schedule regular inspections, especially after severe weather, to identify any hail cracks, loose mountings, or other damage caused by wind or debris before it becomes a bigger problem.

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Years of experience in translation and a love of nature help Julia find the right words to encourage going solar. She joined the team in 2023 and is happy to make her contribution to a greener future.

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