Solar panels on flat roofs Many people think that solar panels are for sloped roofing only, but this is not true. Solar panels can be attached to any roof, including flat roofs. The first thing to note is that flat roofing is not completely flat. There is always a slight pitch to allow water to drain away. For a roof to be considered flat, it will have a slope that is only 16.7% or less, with the pitch located near the gutters or roof edge.

Solar Panels On Flat Roof

When it comes to solar panels on flat roofing, the concern is that they might interfere with drainage. But, this is not true either because the roof was designed with drainage in mind, so the solar panels will not affect this. In fact, the slight pitch will keep the solar panels from getting water damage too. So, how do you attach solar panels to a house with a flat roof? There are two types of solar racking systems for flat roofs. One type is bolted in the same way as with pitched roofing, and the other uses a ballasted rack. These racks use weights to keep the panels in place. There is no drilling or bolting for these racks, but they do add extra weight to the roof. You should take time when making a decision about solar panels for your flat roof and consult a professional installer. To help you get started, this article will review how these systems work so that you are prepared for your discussion with your installer. Attached Solar Racking This is the racking that is similar to what is used for sloped roofing. These racks are attached with bolts or screws into the roof. Mounts are used that are fastened to the roof deck which means drilling into the roof is necessary. Once properly secured to the sheathing your solar panels will be secure. Even the toughest winds won’t blow them away. With this type of rack, it is essential to make sure the mounting points are waterproof. Because you have drilled into the roof, leaking is a potential problem. So, make sure you waterproof these mounting holes to protect your roof structure.

Ballasted Racking Systems

Ab ballast is a weight that holds the panels in place so this type of racking uses weights like concrete blocks, to hold the system in place. In some cases, a few fasteners may still be required especially if the roof has a slightly higher slope. In earthquake-prone areas like California, fasteners are almost always included with ballasted systems for extra security. Ballasted systems are quicker and easier to install as they do not involve drilling into the roof, so there is less labor and less risk of leaking. The downside is that ballasted systems add considerable weight to the roof so it is important to understand the load-bearing capacity of your roof before choosing this option.

Tilted Racks

This is not a third system, but an option for panels. Most solar racking systems will have a slight tilt to them already, but if you want more tilt to catch more sun, tilted racks are available. The standard small tilt on racking systems is not enough to reach the ideal tilting angle for most locations in the US. Tilted racking systems are the solution and are available with both ballasted and attached mounts. The tilts are fixed, which many people do not realize. They are not motorized for you to tilt as the sun’s position changes. It is also important to note that with these systems, you won’t be able to place multiple rows of panels close together. This will cause shadows, making these systems not a good choice for smaller rooftop spaces.

Choosing The Right System

If you wanted solar panels and always thought you couldn’t because your roof was flat, you can now see that it is possible. You have options when it comes to choosing a solar panel system for your flat roof. This means there are a few things to consider when deciding on the system. Which system does your installer recommend and why? Review the structural engineering report of the roof with your installer and never agree with an installer that recommends a ballasted system without first doing an engineering review.

Final Thought

What angle will the panels be and does your installer think you should get tilted racks? There is no right or wrong choice because every roof is different as is every situation. Work closely with your installer to evaluate the benefits and tradeoffs for each option. A professional and experienced installer will help you navigate through the options and explain everything so you can make an informed decision. If you’ve decided it’s time to go solar, reach out to us today.

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