What Is The Best Roof Type For Solar Panel Installations?

Carlos Huerta

Table of Contents

    Solar power has become increasingly popular in recent years as people look for ways to reduce their carbon footprint and save money on their energy bills. One of the most important factors to consider when installing solar panels is the type of roof you have. Different roof types require different installation methods as well as equipment, which can affect the efficiency and effectiveness of your solar panels. Let us analyze the types of roof materials and find out which are the best for solar power installations.

    Asphalt Shingle Roofs

    Asphalt shingle roofs are by far the most common type of roof in the United States. They are affordable and easy to install. They also happen to be one of the best fits for solar power installations. Asphalt shingles are strong enough to support the weight of solar panels, and they have a relatively flat surface that makes it easy to mount the panels. Additionally, asphalt shingle roofs are not as slippery as other types of roofs, which can make it easier, cheaper, and safer for installers to work on.

    For these reasons, asphalt shingle roofs are one of the best roof types for solar power installations. Keep in mind though that penetration in this type of roof is needed to install the PV modules and that they last between 15-25 years depending on the type of shingle, meaning that you may need to replace the roof at least one time during the lifespan of the PV system.

    Figure 1. Asphalt Shingle Roof Type. Source: Bill Ragan Roofing

    Metal Roofs – Corrugated/Trapezoidal

    Metal roofs are another option for solar power installations. They are lightweight, durable, and long-lasting, which means they can support the weight of solar panels without any issues. Additionally, metal roofs are great for solar power because they reflect heat and light, which can help keep your home cool in the summer months.

    The downside of these types of roofs for solar power installations is that there are penetrations involved and that the design and selection for solar racking can be tricky, especially for trapezoidal roofs. Compatibility will depend on the shape and pattern of the trapezoidal roof shape. A big plus for this type of roof is that they are estimated to last over 50 years.

    Figure 2. Trapezoidal Roof Mounting. Source: Land Power Solar

    Tile Roofs: Clay and Concrete

    Tile roofs are a popular choice in areas with warm climates, such as California and Florida, particularly for high-end houses. Tile roofs are often divided into two big groups, clay tile, and concrete standard tile roofs. They are durable, long-lasting, and offer excellent insulation against heat and cold. They also look great on the roof. The best thing about them is their durability, providing nearly 40 years for concrete tile and up to 100 years for clay tile.

    Both options can be used for solar panel installations, however, tile roofs can be a bit more challenging to work with when it comes to solar power installations.

    Between the two options, concrete standard tile is the best choice as there are many racking manufacturers in place that will offer some type of system configuration for concrete tiles. However, things change when we are dealing with a clay tile type of roof because these tiles are quite fragile and can easily be broken when walking over them. Hence, the installers will need to take extra care when mounting the panels to ensure that they do not damage the fragile tiles. This often generates issues when installing solar panels and you may find it hard to have someone willing to install on a clay tile roof and do so properly. Not to mention the much higher installation cost of doing so.

    This is why we can say that while concrete standard tiles can be an option for solar panel installation, clay tile roofs are not good.

    clay tile
    Figure 3. Solar panels on a clay tile roof. Source: Go Green Solar

    Slate Roofs

    Slate roofs are one of the most expensive types of roofs, but they are also one of the most beautiful and long-lasting. They are made from natural stone, which gives them a unique and elegant look. The best thing about slate roofs is that they can last up to 100 years. However, similar to clay tiles, they can be delicate and break during the installation process. The installers will need to take care to ensure that they do not damage the slate tiles when mounting the panels. For these reasons, while feasible, it is not the best type of roof for solar panel installations.

    Figure 4. Slate Roof type. Source: Legacy Service

    Flat Roofs

    Flat roofs are a popular choice for commercial buildings, but they can also be a great option for residential homes. Flat roofs are easy to work with when it comes to solar power installations because they have a large, flat surface that makes it easy to mount the panels. Additionally, flat roofs are often made from materials that are resistant to weather and other types of damage, which means they can support the weight of solar panels for many years. The best thing about flat roofs for solar panels is that this type of roof allows to set up the most optimum orientation and tilt for solar power production.

    Flat roofs can also be done with different roofing materials, the most popular being modified bitumen, tar and gravel, EPDM, TPO, and PVC membrane. Solar power installations on flat roofs will often be done using a ballasted type of mounting system, which anchors the solar panels to the roof by using concrete pads and not drilling into the roof. Although more complex and probably more expensive, if you have a flat roof, solar panels are still a very good choice.

    Figure 5. TPO Flat Roof. Source: Three Tree Roofing

    Wood Shake

    Probably the worst choice for solar panel installations is a wood shake type of roof. The reason is that they are often not allowed to have solar panels installed on top of them because there is the risk of a fire hazard. Besides, they often degrade badly and are highly susceptible to moss. Hence, it is not recommended, at all, to combine wood shakes with solar pane

    Figure 6. Wood Shake Roof. Source: Rain Tree Roofing

    Standing Seam Metal Roofs

    Finally, reaching the last option in the list, there is the standing seam metal roof which is a great option for solar power installations. They are made from long, continuous panels of metal that are connected by raised seams. This design creates a smooth, flat surface that is easy to mount solar panels on. Additionally, roofs are extremely durable and long-lasting, which means they can support the weight of solar panels without any issues. In fact, they are rated to last between 50-80 years in general.

    The best thing about this type of roof is that the mounting system used for solar panel installations often does not require penetrating on the standing metal seam. The standing seam panel is designed with vertical ribs at the edges which can be used by solar panel racking systems to attach the modules to the roof without needing penetrations.

    seam roof
    Figure 7. Solar panel installation on a standing metal roof. Source: Renusol.

    The Bottom Line: What Is The Best Roof Type For Solar?

    The best roof types for solar power installations are those that are durable, long-lasting, and have a smooth surface that makes it easy to mount the panels, and that also have lower installation costs.

    Among the options, asphalt shingle roofs have the cheapest replacement and installation costs while also having a high flexibility and variety of options, making it definitely among the top 3 options for solar. However, they often do not last as much as other options in the market, potentially needing replacement at least once during the lifespan of the PV system. Considering that removing the panels for the roof replacement will carry on additional costs, the profitability seen at the initial investment can fade over time.

    Flat roofs, on the other hand, have the flexibility that solar power installations need to adjust tile and orientation which can often prove beneficial. However, the extra racking and mounting system type required to keep the solar panels attached to the roof can increase costs and make the installation harder.

    Hence, the standing metal seam roof would probably be the best option if you are thinking of replacing your roof, or build a new shed, garage or barn and then install solar panels. The roof is expected to last a long period of time (much longer than the panels) and since there are no penetrations required by the mounting system to install the solar panels, the integrity of the roof will not be affected in any way. While more expensive than asphalt shingles, over time the standing metal seam can prove to be a trouble-free, reliable, and accessible option for solar panel installations.  

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