Solar Panels

Mounting Solar Panels on a Shingle Roof: 7 Tips

By:Michael Johns

solar panels on a shingle roof

There is a very good chance that your house has a shingle roof.

The popularity of this type of roof has skyrocketed in recent years thanks to reduced costs and decent durability.

In fact, it’s estimated that 75% of homes in North America now use asphalt shingle roofing.

This means it’s very common to see solar panels mounted on a shingle roof and installers are well trained in dealing with this material.

When mounting solar panels on a shingle roof, there’s a number of things you should be aware of to aid the chances of success.

Correctly installed solar panels should last for decades, 25 years or more, and even help to protect your roof to increase its lifespan.

Contrastingly, if mistakes are made you could be left with a leaky and dangerous building!

7 Tips for Installing Solar Panels on a Shingle Roof

Let’s discuss the key factors to look at during the addition of solar panels to your home.

Provide Roofing Documentation

To help your solar panel installer out, you should give them any information you have about your roof. You will likely have this if you have had a new roof installed during your time at the property.

Solar panels installers are unlikely to be professional roofers so they will be grateful for any information about the materials and structure they are working on. You can even ask the manufacturer or original roofer for this information. This can also identify any issues that might breach the roof warranty or worries the manufacturer might have.

High Quality Flashing

With the growing number of solar panel systems on the market the choice of flashing is incredible too! The flashing is an integral part of the installation and helps to keep your roof waterproof at the mounting points. 

You should ensure the correct high-quality flashing is used for your shingle roof. This includes features including rust-proofing, waterproofing, easy installation, and durable performance. In simple terms, it should last the complete lifecycle of a solar panel system. This ensures water will be diverted away from the mounting holes.

Metal anchors with flashing installed on a shingle roof as the connection point to support solar panels
Metal anchors with flashing installed on a roof as the connection point to support solar panels

Mount on Rafters

For less experienced installers finding the rafters to drill into can be a little tricky. It is critical that the roof mount is firmly attached to the wooden rafter beams that support the shingle.

Often they can be difficult to identify and drill firmly into the center. If a mistake is made and a drill hole is made away from a rafter it should be sealed to avoid future leaks.

If a mount is attached without the support of a rafter the weight of a solar panel is likely to cause damage. This is because there is not much strength holding everything in place and each panel can weigh upwards of 40 pounds!

Use Proper Sealant

Not all sealant is the same and it can change depending on where you live. The properties of sealant change at different temperatures. So a hot climate requires something different to a cold climate.

For best results, you should try to use the same sealant as the roofing material. Plus check the top temperature performance, a roof in summer can get extremely hot when bathed in sunlight all day. Sometimes this heat can climb to well over 150 degree fahrenheit.

Using the wrong sealant can cause disruption to your pre-existing roof and lead to leaks when the rain returns.

Correct Length Screws and Washers

Once again there is a wide range of mounting systems on the market. All require a different size of screw. Generally, it is best to use a system where the screw is combined with the flashing or aluminum plate. 

Of course, the screw must be long enough to sit deeply into the wooden rafters. Plus it needs to be strong enough to cope with aggressive weather such as high wind and heavy snow. You don’t want them bending or ripping out under the stress.

Adding to this, the screws must use a (EPDM) gasket washer as they are brilliant at sealing off from water.

Don’t Remove Shingle or Nails

Most building regulations stipulate that a minimum number of nails should fasten the shingle tiles which is specified by the manufacturer.

However, some flashing manufacturers may advise the removal of the shingle fastening nails to make installation easier. This is not considered a good idea and you should avoid removing the securing nails.

Adding to this, there should be no removal of any of the shingle roofing material to make way for the solar panel. This will reduce the structural integrity of the roof and again lead to leaks and future damage.

Distribute Weight Evenly

Solar panels are highly durable pieces of equipment made from tempered glass and anti-corrosion aluminum. This makes them very heavy, especially when you get up to the 72 and 78 cell products.

The key to a great installation is evenly distributing the weight evenly across mounting points and roof. This reduces the torsion and stress through the structure. Ultimately, it reduces the effects of contraction and expansion from thermal changes to deliver a reliable waterproof result.

Benefits of Mounting Solar Panels on a Shingle Roof

Now you’ve understood the problems to avoid when installing solar panels on shingle, let’s look at the big advantages.

Excellent Life Span

Shingle roofs have an excellent lifespan and should last 20 years or more. This makes them a brilliant match for solar panels which also have a lifespan of over two decades. 

Common Job for Installers

With such a large number of homes and buildings using this type of roofing material, solar panel installers are very used to the work. Any decent company should have no issues carrying out the installation.

Quick to Complete

It should also be relatively quick to complete the installation. With the correct mounting system and flashing the solar panels can quickly be mounted. Professionals can drill pilot holes through shingle and into the wooden rafters without many complications.

Final Words on Solar Panels and Shingle Roofs

As you can see, it is not a problem to mount solar panels on a shingle roof. 

It is actually one of the most common materials used on buildings across North America. 

This means installers will be confident and well trained in completing the project.

The tips above should help you check that everything is being carried out in a professional manner and help you give the correct information for the job.

Getting a new roof? Check out my guide to the Best Roof for Solar Panels.