The Hog Ring Gun by Slick Tools is used to join sections of wire mesh fencing for solar critter guard.
Pests threaten the performance and longevity of solar systems long before a chewed wire exposes the problem. Reduced energy generation and costly structural damages are at stake, and as much as racoons may be responsible for them, they’re not the ones held accountable.
For solar installers and contractors, understanding and implementing the latest effective pest exclusion solutions is not just a value-added service. It’s a critical part of ensuring the long-term viability of solar investments and the health of client relationships. In other words: it’s time to retire the plastic zip ties.
Understanding the threat of pests to solar panels
Animal problems can occur anywhere, and sometimes in very concentrated, seemingly inexplicable ways. One neighborhood may experience large infestations while solar users across town remain unaffected. One house may be pest-free until a neighbor installs a critter guard, and the evicted animals move next door.
While specific pest situations vary by region (or even neighborhood block), these are the most common troublemakers for PV systems:
Looking specifically at residential flush-mount solar systems, there are several proven strategies installers can use to avoid infestations and damages.
The latest physical barrier strategies
Physical barriers are a reliable method for protecting solar projects. When installed correctly, these barriers seal off the perimeter of a solar array between the roof and the module frame. Here are the different physical pest barriers for solar arrays:
Fencing material options
CritterBlok Solar Animal Guard Clip by Slick Tools secures wire mesh to panels.
Advancements in wire mesh materials and tools continue to make it a leading choice for pest prevention. Typically available in rolls with widths of 4 to 10 inches, wire mesh can be cut and shaped to fit specific dimensions of a solar array. Any wire mesh worth its weight is made from galvanized steel and coated with PVC or polyester to enhance its durability and corrosion resistance.
To streamline the install process, specialty tools for transporting, dispensing and cutting coiled wire mesh are available. Several manufacturers also offer pre-cut wire mesh panels to accommodate non-uniform surfaces, like tile roofs. These recent developments can significantly reduce installation time.
Another physical barrier option is perforated sheet metal, typically made from corrosion-resistant aluminum with a black polyester coating. The key difference here is the attachment method, which is further explained below.
Lastly, wire spikes are a deterrent available primarily to prevent birds from perching and nesting on or around solar panels. While effective against birds and relatively easy to install (they can be adjusted to conform to non-uniform roof surfaces), they may leave openings for rodents or other small mammals to get through.
Attachment methods
Raccoon damage underneath an array.
Another important consideration in pest exclusion is the attachment method for the deterrent you choose. Installers need to weigh the ease of installation, integrity and longevity of the methods available.
Rail mount
The rail mount method attaches wire mesh directly to the PV racking components — not the modules themselves. This allows for easier serviceability in the future, as PV modules can be removed without disturbing the barrier. This method provides strong attachment points capable of resisting snow and wind loads, and uses inexpensive self-tapping screws for attachment. The rail mount method is typically used in conjunction with wire mesh C- or L-channels (more on that below).
Specialty clips
Specialty clips, like the ubiquitous J-hooks consisting of a hooked wire and pushnut, attach wire mesh directly to the PV module frame and are quick to install. The downside of all such clips is that they must be removed and replaced during any future service on the PV array. Fortunately, there are several new clips on the market that grip mesh more securely than J-hooks and are easier to remove and reuse. While the installation speed and low cost of J-hooks is attractive, installers must weigh that against their durability and serviceability. Note that most specialty clips require the PV module frame to have a flange on its underside, which is not present on certain modules (such as LONGi).
Adhesives
The appeal of adhesive (typically double-sided tape) attachment is its broad compatibility with PV modules. A strong attachment is possible if installers wait for temperatures to fall within the required range and clean the mating surfaces meticulously. Unfortunately, the more durable an adhesive bond, the more difficult it is to remove and replace should the PV array require service down the road. Installers should carefully consider the age and health of the PV array (and its likelihood of requiring future service) before using this style of attachment.
Installation best practices
Following these best practices during installation is key to achieving optimal and long-lasting results for physical barriers:
A squirrel’s nest underneath solar panels.
Bending mesh wire
The integrity of a wire mesh barrier is vastly improved when creased along its length. Bending mesh into an L- or C-channel allows for longer spans between attachments because the creases add stiffness and strength.
Secure joining techniques
In the past, installers have used plastic zip ties to join multiple sections of wire to create a continuous barrier around the solar array. These have proven ineffective for long-term use due to exposure to UV rays that degrade the plastic, causing them to become brittle and break over time. Instead, installers can opt for durable alternatives like metal hog rings and stainless steel zip ties. Metal hog rings are an economical and efficient solution, especially when used with a specialized hog ring tool, which allows for quick installation.
Considering non-physical pest deterrents
While physical barriers offer the most reliable long-term solution, there are other strategies that use light, high-frequency sound or smells to make environments less appealing to animals. Non-physical deterrents may be worth considering for specific use cases — particularly large commercial sites where physical exclusion is not economical — but their effectiveness varies.
Protecting the lifespan and performance of solar systems is important to system owners, and thus to installers’ reputations and client relationships. Fortunately, recent innovations in fencing and attachment products — and the tools to transport, fold and cut wire mesh — make it easier than ever to incorporate a strong pest exclusion strategy into solar installation.
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