Can You Put Solar Panels On A Metal Roof?

by Jenny Kim | Last Updated: November 4, 2021
 

As the world continues to embrace the use of more sustainable energy sources, solar panels are becoming more and more popular by the day. Metal roofs on the other hand have massive benefits, and, although they make up just a small percentage of residential roofs today, they are growing in popularity.

But, if metal roofs and solar panels have become a critical part of homeowners’ lives, are they compatible with each other? Perhaps, this is a question you’re asking yourself by now! The good news is, you can install solar panels on a metal roof. Metal roofs are especially considered the best roof materials for solar panels because of their durability. They’re a long term investment. If your roof fails early, this means you’ll incur an extra expense to remove the solar panels before any repair can be done.

How easy or difficult it is to mount solar panels on metal roofs however depends on the kind of metal roof you have. Let’s review various types of metal roofs, and once you find yours, you’ll see how you can safely install solar panels on them.

Vertical seam panels

This is probably the most common type of metal roof. They’re different from the normal asphalt roof shingles. Vertical seam panels are flat metal panels that have seams running down the roof at regular intervals. There are multiple types of vertical seam panels. Let’s pick a few and check how you can install solar panels on them.

Standing Seam

Standing seam is probably the easiest metal roof to install solar on. If you decide to install solar on your standing seam, you can choose between thin-film solar panels or conventional crystalline solar panels.

When installing conventional solar panels on standing seam roofs, the solar panels clamp onto the ‘seam’ at the point where the two panels connect with each other. The clamps squeeze the seam tightly rather than going through the seam. That’s to prevent the wind from pulling the solar panels off. Since drilling isn’t needed, unlike with asphalt shingles, the roof remains leak-free.

Do you want something sleeker? A thin-film solar panel will match your needs. Thin-film solar lays flat against the metal roof, making direct contact. The panels are positioned between the seams. This gives your installation a discrete and natural look.

Other Vertical Seam Roofs

There are an endless variety of vertical seam roofs, hence solar companies produce various kinds of hardware to attach many of these. For example, SnapNrack manufactures attachment points that won’t crush the metal below the hardware of your corrugated metal roof.

If you opt for a different vertical seam metal roof, there are chances someone is producing a solar attachment point for that. Make sure to ask your installer what you can find in the market!

Metal roof shingles

You’ve probably come across these metal roofs at some point, but they can be a bit confusing since they’re manufactured to look like more conventional roofs such as clay tile, asphalt shingles, wood, slate, and others. These metal roofs either have granules held tight on the surface, or they’ve been painted to look like composition shingles.

Installing solar panels on metal roof shingles is more difficult than doing it on any other metal roof. Unlike on vertical seam metal roofs, there’s not a fast way of doing the setup for metal roof shingles. More labour plus tweaking is required from the installers while working on the roof for safety, and to prevent any leakages.

In fact, maintaining a watertight roof is the main issue when it comes to metal roof shingles. With conventional roof shingles, you can just place a flashing on and apply a sealant. But metal shingles require doubling or sometimes tripling up on flashing and making water runoff points below metal flashings.

Let’s focus on two of the most common metal shingle types: batten mounted and interlocking. Both of them give installers a hard time.

Batten Mounted Metal Shingles

These metal shingles are usually installed on a wooden lattice, called a batten, that’s then attached to the roof. While putting solar on batten mounted metal shingles you should place the solar flashings between two layers of metal shingles. The shingles have to be removed to connect the mounting hardware with the roof, then the layers of shingles are put in place so that the attachment point can stick out. To prevent any leakages, a waterproof sealant is placed on all the joints.

Interlocking Metal Shingles

Some metal shingles interlock with shingles on the upper and lower side, creating a windproof roof. If you are installing solar panels on interlocking metal shingles you’ll need a waterproof membrane placed in contact with the sublayer of the roof below every shingle.

As you can see, placing solar panels on metal roofs is possible. Installers are only required to attach or cut and seal on the structure to make a strong and waterproof system.

Pros and Cons of Installing Solar Panels on Metal Roofs

A system of solar panels and a metal roof offers incredible benefits to homeowners. Let’s cut to the chase and look at what you stand to gain by installing solar panels on a metal roof.

Pros

1.   It’s simple to instal solar panels on a metal roof

Typically, when mounting solar panels on your roof, the installer drills holes on the roof to attach the mounting for the panels. Making holes on your metal roof isn’t a great idea. It causes leaks on the roof.

If your roof is metallic, high chances are your installer won’t need to drill any holes in your roof. This eliminates the possibility of leakages and other roof-related issues down the road.

2.   Metal roofs last long

Solar panels have great durability, ranging between 25 to 30 years. This means your solar panel is likely to outlive your roof, which of course would mean an extra expense for replacements and reinstallation.

Metal roofs are the most durable conventional roofing material you’ll find out there. If you’ve installed a metal roof on your house, it will outlast your solar panels, so you don’t have to worry about extra expenses in the long term.

3.   Metal roofs can host standard PV panels and thin-film panels

Homeowners often install standard silicon photovoltaic solar panels. However, if your roof is metallic, there’s one more available option – thin-film solar. It can only be installed on specific roof types, and a standing seam metal roof is an ideal surface.

PV panels are more efficient per square, which is desirable. Thin-film panels are also an excellent choice due to their ease of installation and cheap manufacturing cost.

4.   Guaranteed cooling benefits

A combination of solar panels and a metal roof might also mean a cooler space for you. So if you live in a warm area that requires constant ventilation, a cooler area can save you ventilation and energy costs.

Cons

Mounting solar panels on a metal roof doesn’t come without some downsides. So, what problems will you face while your solar panels are placed on a metallic roof?

1.   Metal roofs can rust

It should be noted, however, that metals are prone to corrosion, so check well while attaching the brackets to the parts of your metal roof solar panels. Otherwise, you won’t enjoy the benefits of a long-lasting roof. A corroded roof is also not appealing to look at. Watch out!

2.   It can be expensive

Overall, a system of metal roofs and solar panels is more expensive because metal roofs cost more than shingles. Installing solar panels on a metal roof also requires more skill and labour.

Installing Solar Panels on a Metal Roof FAQs

Is it safe to put solar panels on a metal roof?

The answer is an astounding “yes”. A qualified roofer and solar installer working together can successfully mount solar panels on a metal roof without causing damage.

Do I need to reinforce my roof for the solar panels?

Most solar panels could last more than 25 years. Therefore your roof should have the capacity to withstand the weight of solar panels for all those years. If your roof is close to the end of its life, then you’ll probably need to do some reinforcement, replacement or repair before you can place the solar panels.

Can the weight of solar panels damage my roof?

In most cases, solar panels weigh about 40 pounds. This means, for pitched roofs, solar panels add about 2.8 pounds per square foot.. If your roof is in good condition it can withstand this. However, if you are unsure an installer can assess your roof and advice if repairs are necessary before installing solar panels.

Will a metal roof raise my insurance?

Metal roofings have a lot of positives that will not likely increase the amount you need to pay for home insurance. It has a great lifespan, and handles wind, rain, hail and is fire resistant.

Why shouldn’t I place solar panels on my metal roof?

Metal roofs are good with solar panels. But if your roof is too small, you should rethink the idea of mounting solar panels. Solar panels use sunlight to generate electricity, and the more sunlight they absorb, the more power they generate. If your roof is small, solar panels won’t generate enough electricity, and you won’t see the impact you would want on your bills.

 

Fixing solar panels for metal roofs is a great idea. But, before proceeding with the installation, you need to consider a few factors. If your metal roof seems too old, you may want to replace it before you move on. And if your roof isn’t strong enough, rectify that to avoid problems when the panels are ready to be mounted.

 
Jenny Kim - President, joined DC Sun in 2016 with the simple goal of helping make solar power more accessible and affordable to anyone that wants to take advantage of the many benefits. As President, she has led an effort to assist more than 400 homeowners in the Washington DC area to go solar. Jenny holds a Master of Science in electrical engineering from Virginia Tech where she paid her way through college as a top-performing inside sales representative for SolarCity. You can connect with Jenny on LinkedIN.