Can You Put Solar Panels On Metal Roof?
December 22nd, 2023 | Reading Time: 9 minutes
Yes. Metal roofs are one of the best roofing materials to install solar panels on. However, the installation method varies greatly depending on the metal roof type. You want to ensure that the roofing attachment is specifically designed for your metal roof type. Below you will find the variety of factors you should consider when installing solar panels on a metal roof.
What Type Of Metal Roof Are You Installing Solar Panels On?
The first thing you need to figure out is what kind of metal roof you are planning on installing solar panels on. The type of brackets or clamps that are used are completely dependent upon the type of metal roof that you have. A good professional tip is to actually reach out to your metal roofing manufacturer and confirm that the bracket or clamp that’s being used is compatible with their metal roofing tight. The reason why we usually recommend this is to ensure that installing solar does not affect your roof warranty.
Standing Seam Metal Roof
Undoubtedly, the absolute best type of roof to install solar panels on is a standing seam metal roof. When installing solar on a standing sea metal roof, the solar panels are actually attached to the roof using clamps that pinch the vertical seams. This means that there are no penetrations through the roof at all, which means the chance of a roof leak is almost 0%.
The negative of a standing sea metal roof is that it is the most expensive type of metal roof. If budget is not a top concern, then we would recommend a standing seam metal roof.
Trapezoidal Corrugated Metal Roof
A common style of metal roof that we install solar panels on is a trapezoidal corrugated metal roof. There are a variety o of different ways to install solar panels on a corrugated metal roof. Below ar the 2 most commons options
Option 1: use a bracket that screws into the humps of the roof as illustrated below. The positive of this type of bracket is that the screws are raised up so that way when it rains the water never really touches the screws. The negative to this type is that it’s not actually being screwed into the structural metal or wood that is holding up the roof. We have installed thousands of solar systems this way, and we have never had a issue with it.
Option 2: the second option is to install a bracket that sits in the valleys of the corrugated metal. The main benefit of this style is that you can screw these brackets directly into the structural member holding up the roof. This is going to lead to a higher uplift resistance to wind. 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. As long as they are installed to manufacturer specifications, you should be able to avoid any roof leaks.
Example of a Bracket installed in the valley of a corrugated metal roof
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.
If you live in an extra windy place, you can take extra safety measures. The main thing that you can do is to install additional roof brackets or clamps. Typically these brackets are installed 4 to 6 feet apart on the roof; you can go as little as 24 inches apart on the roof. These additional brackets will increase the uplift resistance of your solar system.
Rail Direction on Metal Roofs
When you install a solar system on your metal roof, there are going to be metal rails that run along the roof, and the solar panels will actually sit on those metal rails. It is important to know that if your metal roof is fully supported by plywood, you can run the metal rails and any direction that you want. It is most common in these situations to run those metal rails parallel to the gutter.
However, if you have perlins, which is holding up the metal roof, which is extremely common with corrugated metal roofs, you need to run your rails vertically. The reason for this is that the pearls are already running horizontally with the roof, and it will not evenly distribute the load.
Do you need plywood under the entire roof?
No, you do not need plywood under the entire roof. However, if you are replacing your roof or doing new construction, we do recommend putting plywood underneath the metal roof if it is within your budget. We have found that installing the plywood underneath significantly increases the metal roof’s strength. The reason why this is nice is that when you add solar panel to your roof, you are adding approximately 4 pounds per square foot to it.
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.