" The Best Roof at the Best Price"

Solar Panels

Rooftops are great for solar, but only when important considerations are addressed
 by Tony Ruffine from GAF



As North America’s largest roofing manufacturer, we know that rooftops are a great location for solar. Roofs are out of the way, tend to have the least shade on a property, are close to utility hookups and usually do not need additional infrastructure. As a result, approximately 80% of solar installations take place on roofs. We have worked closely with the solar industry for several years and are big advocates of rooftop solar.

Working with the best players in the industry, we have seen some great solar projects on top of our roof systems. Unfortunately, many solar buyers and installers do not understand the interplay between the roofing system and solar. Most of us have heard a job sold with some variation of the line: “There are no penetrations so it does not affect your roof warranty.” When we at GAF hear that, we can be almost certain there will be a problem.




Choosing the Right Installer
A lot of solar installers take the roofing piece for granted or do not have the experience with roof top installations to understand the challenges of each roof. That is why choosing an EPC that is familiar with the roof, such as
Advanced Green Technologies, is crucial. The property owner should insist on a solar installer with genuine roofing experience. Here are some tips for choosing a qualified solar installer:
• Ask the installer about other rooftop installations they have completed.
• Make sure the installer is respected by roofing-system providers.
• Ensure the company has installed solar on multiple roofing systems using a variety of technologies.
• The installer should be able to discuss rooftop conditions, know how the roof drains, have a strong familiarity with wire management plans, provide roof replacement and repairs, take down and re-install a system during roof replacement and repair and can provide follow up maintenance services.


Proper Planning
If a property owner is considering solar, the roof system should be designed with the future installation in mind. Design considerations like slope or placement of drains and scuppers should be done to allow maximum solar coverage. The roof system should also be chosen to support solar. High-density cover boards, for example, should be used when solar will be installed.

Membrane systems should not be loosely laid or mechanically attached, but should be fully adhered. Higher performance membranes provide cheap insurance up front. Walkway pads should be used around the solar (and slip sheets are usually recommended underneath). Most importantly, the roof installation needs to be staged to facilitate the solar installation, considering both schedules.



Common Installation Problems

A successful solar installation is not just one that generates the required amount of electricity. It also has to leave the building in serviceable condition. There is no such thing as a good solar installation on a leaky or damaged roof. Even today, in states where there is a long history of solar installations, we see problems when the solar installer did not understand or take into account conditions on the roof. A few of these problems seem to come up repeatedly:

1. Not matching the roof life to the solar installation’s life. This one should be obvious. A solar installation may generate power for 20 years or more and have financing or PPA lengths just as long. Putting a solar installation that may last 20 years on a roof that, like many new construction roofs, is only designed to last 10 years is asking for problems. A variety of roof systems, however, can last 20 years. Also, membranes are designed for conditions on solar rooftops and so can be warranted for 35 years. Membranes are the protective, waterproofing top layer of a roofing system.

2. Not matching the roof design to solar. Because solar has specific performance criteria, there are points to consider when choosing a roof system to ensure the best solar performance. Solar panels, for example, tend to work best in cooler environments, so a cool membrane can provide better electrical output. Roof systems are also not usually designed for the weight of solar projects or for the foot traffic that installation and maintenance can bring. Understanding the roofing membrane is even more important when considering the potential for directly attached panels in the future. Many membranes will have compatibility issues with these designs. Ensuring the roof is solar-ready up front will avoid a lot of unnecessary work in the future.

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