Rooftop Integrity: The Ballasts vs. Mechanical Attachment Debate

As a commercial solar installer, you’re probably familiar with the on-going debate regarding ballasted racking vs. mechanical attachments. This argument is rooted in the sentiment that mechanical attachments jeopardize the roof and void the  commercial building roof warranty. 

This is not true. 

The supposed solution to this problem is to use ballasts to secure solar panels. Ballasted systems are typically concrete blocks that add weight to your solar panel mounts, holding your solar panels in place without penetrating the roof. Thanks to this perceived simplicity, ballasted mounts are seen as cheaper, easier, and safer than mechanically attaching your solar panels. 

Unfortunately, a cheap installation can be the riskiest option of all. 

Here are some common misconceptions about the mechanically attached vs. ballasted debate, and how you can explain it to your customers. 

Misconception 1: Using ballasts to install your solar panels causes less damage than penetrating your roof using mechanical attachment. 

As a solar installer, you’ve probably had the experience of dealing with a customer that refuses mechanical attachment because they can’t bear to drill holes in their roof. To the layman, holes in your roof are bad. The misconception that holes in your roof mean leaks, loss of insulation, and other costly problems make building owners wary of a mechanical attachment installation. 

However, to install a system ethically that will last, it's important you consider the longevity of the roof and what cutting corners on an installation can do in the long run.  

  • Concrete ballast blocks are heavy. The rooftop is usually not designed with the expectation of holding so much additional weight (dead load). This excessive and concentrated weight puts your clients’ roof structure at risk. In high snow load areas or locations with seismic activity, the additional weight can be a huge liability potential for a collapsed roof. 

  • Concrete ballast blocks are not secured. There is potential for these blocks to move independent from the roof structure causing wear damage, potential for structural failure, or issues with the solar array if these systems shift. 

  • Concrete ballast blocks dissolve. The weight provided by concrete ballast blocks could change over time as these blocks are exposed to weather damage. These systems sit on the roof and do not connect to the building which is a nonpermanent solution for a 30-year investment. 

While ballasted systems are easier to approve and simpler to install, the decision to use this method to secure a solar array can come back and hurt you and your client in the long run. 

Misconception 2: Penetrations in your roof for solar installation purposes are not covered by your roof warranty 

Before installing a solar array, both you and your customers should be familiar with the customer’s roof warranty. No questions about it. 

Penetrations in your customer’s roof for the purpose of installing a solar array will not violate most roof warranties. Penetrations should also not cause roof leaking if done properly.  

For these reasons it is critical to have a manufacturer approved roofing contractor approve the method of installation and certify their work complies with manufacturer best practices so the client is protected. 

Factors that will affect your customer’s roof warranty include: 

  • Improperly installing solar panels 

  • Tearing the roof’s membrane 

  • Using low-quality materials/racking systems 

  • Failing to take waterproofing precautions. 

  • Wear and tear from the proper O&M required to maintain the roof and solar array 

To ensure your customer a solar install that will stand the test of time, download our Ethical Install Checklist below.

Ethical Install Checklist.PNG
Renee Holden