Rodents in Solar Panels: Perth’s Rooftop Rat Problem

• The gap under rooftop solar panels is warm, sheltered and hidden, which makes it a favourite nesting spot for roof rats in Perth.
• The main risk is chewed wiring under the panels, which is a fire and system-fault hazard, plus droppings and staining that cut output.
• Signs include scratching near the roof after dark, droppings on panels or in gutters, chewed cabling and a sudden drop in solar output.
• The fix is rodent mesh fitted around the panel array plus sealing roof entry points, not baiting on its own.
• If the roof noise is heavy and slow, it may be a possum, which is protected in Western Australia and handled differently.

Perth has taken to rooftop solar like almost nowhere else, and the rats have noticed. The gap between a solar panel and the roof is warm, dry, shaded and hidden from predators, which is close to ideal for a nesting roof rat. Once they move in under the array, the problem is not just noise. Rats gnaw, and the cabling running between the panels is right there to chew on.

Chewed solar wiring is a genuine hazard. It can cause a system fault, drop your output, and in the worst case start a fire on the roof. On top of that, droppings and urine build up on the panels and in the gutters, staining the glass, soiling the roof and cutting how much power the system makes. In Perth’s warm climate, roof rats stay active all year, so this is not a seasonal issue that fixes itself.

The good news is that it is preventable. The lasting fix is to close the gap around the array with purpose-made rodent mesh and to seal the roof entry points the rats use to get up there, ideally after removing any that have already moved in. Baiting alone does not stop the nesting or repair the wiring. This guide covers why it happens, the signs, and how to deal with it.

Table of Contents:

• Introduction
• Why do rats nest under solar panels?
• What damage do rodents do to solar panels?
• Signs of rodents under your solar panels
• Is it rats or possums up there?
• How to stop rodents nesting under solar panels
• Technician insights from Perth roofs
• Perth-specific information
• Practical tips
• Frequently asked questions
• Key takeaways

Introduction

A solar system is meant to sit quietly on the roof and make power. When you start hearing scratching above the ceiling, or your output drops for no obvious reason, the panels themselves are rarely the issue. More often it is what has moved in underneath them. In Perth, that is usually roof rats, and the space under a solar array is one of their favourite places to set up.

This guide is about that specific problem. Why rats nest under solar panels, the damage they do, how to tell they are there, and how to keep them out for good without harming the system.

Why do rats nest under solar panels?

Roof rats are climbers that naturally look for high, sheltered spaces, and a solar array gives them a purpose-built one. The panels sit a few centimetres above the roof, which creates a long, covered cavity that stays warm in the sun and dry in the rain. It is hidden from birds of prey and out of sight from the ground. Add the branches, fences and downpipes that rats use to reach a Perth roof, and the under-panel gap becomes an easy, protected place to nest and breed. Roof rats are the usual culprit, and our roof rat page has the identification detail.

What damage do rodents do to solar panels?

The damage falls into three areas. The first and most serious is wiring. Rats gnaw constantly, and the DC cabling and connectors that run between panels sit right in their path. Chewed wiring can trip the system, cut output, and create a fire risk on the roof, which is why any exposed or damaged cabling should be checked by a licensed electrician or solar installer, not just left.

The second is output loss. Droppings, urine and nesting debris build up on the panels and the roof, and soiled or partly shaded panels make less power. The third is roof and gutter damage. A nest under the array traps moisture and mess against the roof, and the gutters fill with droppings and debris. None of it improves on its own while the rats are still up there.

Signs of rodents under your solar panels

The table below covers what to look and listen for.

Is it rats or possums up there?

Not every roof noise is a rat. Fast, light scratching and scurrying, worse after dark, points to rats. Heavy, slow thumping like footsteps, often with coughing or hissing around dusk and dawn, points to a possum. This matters in Western Australia, because possums are protected and must be handled the right way, so it is worth confirming which one you have before anyone goes near the roof. Our winter rodent guide covers that seasonal and possum side in more detail.

How to stop rodents nesting under solar panels

The reliable fix is exclusion, closing the gap and the routes to it, rather than repeat baiting. The table below sets out the options, and they work best together.

A quick warning on baiting. Tipping bait under the panels does not stop new rats moving in, does not repair chewed cabling, and can leave a dead rat in a spot that is hard to reach and starts to smell. Mesh and sealing are what actually solve it.

Technician insights from Perth roofs

Across Perth callouts, the under-panel nest is one of the most common roof jobs our technicians see, and the owner often notices the output drop before the noise. The chewed leads tend to sit where the cabling loops between panels, which is exactly where a rat sits to gnaw. Droppings streaking down the panels and collecting in the gutter are usually the clearest early sign. And once one array is colonised, the same climbing routes, a fence, a branch, a downpipe, are almost always doing the work, so closing those off matters as much as the mesh.

Perth-specific information

Two things make this a Perth problem in particular. First, the sheer amount of rooftop solar. Perth has one of the highest rates of rooftop solar in the country, so there are more arrays, and more warm, sheltered gaps, than almost anywhere. Second, the climate. Perth’s warm Mediterranean weather keeps roof rats active all year, so there is no cold season that clears them out the way there is down south.

Local building style plays a part too. Single-storey brick homes with tile or Colorbond roofs are common, and large north-facing arrays give rats a long, unbroken cavity to work with. It is also worth remembering that brushtail and ringtail possums are protected in Western Australia, so if the roof visitor turns out to be a possum rather than a rat, it is a different and carefully handled job.

Practical tips

1. Check under the panels and in the gutters for droppings every few months.
2. Watch your solar output. An unexplained drop can be an early sign.
3. Have rodent mesh fitted around the array to close the perimeter gap.
4. Seal roof entry points and trim branches back from the roof.
5. If you see chewed cabling, have a licensed electrician or solar installer check the wiring.
6. If the noise is heavy and slow, treat it as a possum and handle it accordingly.

Frequently asked questions

Why are rats attracted to solar panels?

The gap under the panels is warm, dry, shaded and hidden, which is close to ideal shelter for a roof rat. It also sits high up, where climbing rats naturally look to nest.

Can rats really damage solar panels?

Yes. The main risk is chewed wiring, which can trip the system, cut output and create a fire hazard. Droppings and nesting debris also soil the panels and reduce how much power they make.

How do I know if rats are under my solar panels?

Look for droppings on the panels and in the gutters, listen for scratching near the roof after dark, check for chewed cabling, and watch for an unexplained drop in output.

How do I keep rats out from under solar panels?

Have rodent mesh fitted around the array to close the gap, seal the roof entry points rats use to get up there, and remove any that are already nesting first.

Does rodent mesh damage the panels or void the warranty?

Properly fitted mesh clips to the panel frames without drilling into the panels themselves. To be safe, check with your installer so the fitting keeps your system warranty intact.

Is it rats or possums under my panels?

Rats typically nest in the under-panel gap and make fast, light noise. Heavy, slow thumping suggests a possum, which is protected in Western Australia and handled differently.

Key takeaways

• The warm, hidden gap under solar panels is a favourite nesting spot for Perth roof rats.
• Chewed wiring is the main risk, a fire and fault hazard, and droppings cut output.
• Watch for droppings, roof scratching, chewed cabling and an unexplained output drop.
• The fix is rodent mesh plus sealing roof entry points, not baiting alone.
• Heavy, slow roof noise may be a protected possum, so confirm before acting.

Rats under your solar panels, or output dropping for no clear reason? Our licensed Perth technicians will inspect the roof and the array, confirm whether it is rats or a protected possum, remove them, and fit rodent mesh and seal the entry points to keep them out. Call Tom’s Pest Control Perth on (08) 6202 7096 or book a rodent inspection online.