Solar Panels On Metal Roof: Comprehensive Guide

July 3rd, 2024 | Reading Time: 9 minutes

This guide will walk you through everything you need to know about solar installation on your metal roof. Whether you’re still in the construction process, or your roof is fully functional, solar panels can be an easy way to starting producing your own electricity.

What Type of Metal Roof Do You Have?

The type of mounts or clamps used for solar installation are completely dependent upon the type of metal roof.

Metal Roof Types

Shingle metal roof

Shingle Metal Roof

Standing seam metal roof

Standing Seam Metal Roof

Corrugated metal roof

Corrugated Metal Roof

Shingle Metal Roof

Shingle metal roofs are the least common metal roof type. However, they are an excellent option when it comes to getting solar. Most metal roofs have a 50+ year warranty, so you want to ensure you do NOT void this warranty when you get solar. We always recommend ensuring your solar company works with the company that did your metal roof. The company that did your metal roof is going to have specific requirements for exactly what kind of flashing needs to be used and exactly how they should be installed. We always recommend actually paying the metal roof company to install the flashings. This is critical as it guarantees your warranty will stay intact. 

Standing Seam Metal Roof

Standing seam metal roofs are an excellent candidate for solar, and you could argue that it is actually the best type of roof to put solar panels on. Standing seam metal roofs have vertical seams that run from the gutter to the ridge. The solar system in this situation actually uses clamps, not flashings, and the clamps just pinch the seams on the roof. Each individual seam has its own profile, so it’s important to make sure your solar installer uses the shape clamp that is exactly made for your standing seam metal roof. 

Pro Tip: do not ever allow your install to make any penetrations in your standing seam metal roof. Standing seam metal roofs can last 75+ years, and there is no need for your installer to shorten its life. 

Trapezoidal Corrugated Metal Roof

Trapezoidal Corrugated Metal Roofs are extremely common and are great candidates for solar panels as they tend to last 30+ years. There are two ways to install solar panels on a trapezoidal corrugated metal roof; using a bracket that sits in a valley or a bracket that’s screwed into a hump.

Valley Install

The main benefit of this option is high uplift resistance to wind. When you install the brackets in the valleys the screws are going directly into the structural wood or metal that holds up the roof.  The main negative of this type of bracket is that the screws are sitting in the valleys, which is exactly where the water runs down the roof when it is raining. However, as long as they are installed according to manufacturer specifications, roof leaks should be avoided.

metal roof valley installation

Valley Install Example

valley install example

Hump Install

The positive of a hump bracket is that the screws are raised up, so rainwater never touches the screws.  These screws are only grabbing the actual metal roof itself and not the structural beams holding up the roof. This means that this installation type is much less likely to ever have a leak but you need to ensure that it is designed for the wind speeds in your area so that uplift is not a issue.

If you are in the process of building, we recommend putting plywood underneath the entire corrugated metal roof. This will give the roof much more structural ridigity then just have the roof sit on rafters or trusses. 

metal roof hump installation

Wind & Solar Panels On Metal Roofs

Solar panels put on metal roofs are as wind-resistant as solar panels on any other roofing material.  The industry standard is to ensure that the solar panels are rated for a minimum of 135 MPH of wind.

Pro Tip: If you live in an especially windy area, you can take extra safety measures by installing additional roof brackets or clamps, which will increase the uplift resistance of your solar system.

Rail Direction on Metal Roofs

If your metal roof is fully supported by plywood, you can run the metal rails and any direction. It is most common to run them parallel to the gutter.

However, if you have purlins, which is common for corrugated metal roofs, you need to run your rails vertically to distribute the weight load evenly. We see installers make this mistake almost monthly. Confirm your solar installer has installed on your roof type before, as they are highly likely to make this mistake if they haven’t. 

Does The Thickness Of The Metal Roof Matter?

As long as the metal roof gauge is a minimum of 20, you should not have any problems installing solar panels. If the roof is well-built and supported, it should be thick enough for solar panel installation. If your roof gauge is thinner than 20, we recommend having plywood installed underneath your metal roof, as this will fully support the thin metal. 

Do you need plywood under the entire roof?

No, you do not need plywood under the entire roof but it’s recommended if possible. The plywood significantly increases the metal roof’s strength.

plywood under metal roof

Custom Solar Quotes for Metal Roofs

Curious if solar is a good fit for you? Fill out this form below and we’ll be in touch within 48 hours. Or give us a call at (508) 717-3820 to get started.

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