The gap between a solar array and the roof is about ten centimetres of dry, sheltered, predator-free space. For pigeons and mynas that is close to ideal, and once a colony establishes under an array it does not leave voluntarily.
Most people discover this when the droppings become impossible to ignore. By then the nesting material underneath is usually substantial.
We cover cleaning the mess in bird and possum droppings on roofs and solar panels. This is about stopping it happening again.
Why it is worth dealing with
The output loss from droppings on the panel face is the visible problem and the smallest one.
Nesting material blocks the roof. Twigs, feathers and debris accumulate under the array, wash into the gutters, and block downpipes and valleys. A gutter that overflows into the eaves in a storm is a considerably more expensive problem than a dirty panel.
Droppings are corrosive. Uric acid attacks the panel frames, the mounting rails and the roof sheet itself. On a Colorbond roof it will etch the coating.
Cabling gets chewed. Birds and rodents in the same cavity will damage DC cabling, which is a fire risk, not a maintenance annoyance.
Hot spots. Heavy, persistent soiling on part of a panel can cause localised heating and cell damage, not just reduced output.
Health. Accumulated pigeon droppings in a confined roof space carry real respiratory risk, which is why removal is a masked, controlled job rather than a hose-down.
The proofing options
Mesh clipped to the panel frame. The standard approach, and the right one in most cases. Galvanised or PVC-coated steel mesh, typically around 20mm aperture, cut to the perimeter and fixed with stainless clips that grip the panel frame itself.
The critical detail: nothing penetrates the roof, and nothing penetrates the panel frame. The clips grip, they do not screw through. Any installer proposing to drill the roof sheet or the frame to fix mesh is proposing to void warranties and create a leak path.
Solar skirt. A rigid plastic or aluminium trim around the array perimeter. Tidier than mesh and better looking from the ground. More expensive, less airflow, and usually harder to retrofit to an existing array than mesh.
Spikes. Useful on ridge capping and on the panel tops where birds perch, essentially useless for stopping access underneath. A supplement, not a solution.
Gel deterrents and sonic devices. We have not seen either hold up against an established colony. Gels degrade in Sydney sun and the birds habituate to sound.
What voids warranties
This is where retrofits go wrong, and it is worth being specific.
Drilling the panel frame voids the panel manufacturer’s warranty, essentially universally. The frame is structural and part of the weather seal.
Penetrating the roof sheet or tile outside the existing mounting points creates a leak path and will generally void the roof warranty. On Colorbond, a penetration without the right fastener and seal also creates a corrosion point.
Anything that significantly restricts airflow under the array can affect panel performance warranties, because panels are rated assuming a ventilated gap. Mesh is fine. Solid skirting that seals the cavity completely is not, and the better skirt products are vented for this reason.
Disturbing the DC isolator or cabling is licensed electrical work. A proofing installer should not be touching it.
The sequence that matters
Proofing an array that already has a colony under it, without clearing it first, traps the birds and the mess inside. That is the single most common mistake.
The order is:
- Check for active nests first. Native birds and their nests are protected in NSW. Pigeons and common mynas are introduced and are not, but identification matters, and during breeding season this can mean waiting.
- Clear everything out — nesting material, droppings, debris — under controlled conditions with appropriate respiratory protection.
- Clean and disinfect the roof area and the panel undersides.
- Clear the gutters and flow-test the downpipes, because that is where the material has been going. See gutter cleaning.
- Then proof, with non-penetrating fixings.
- Clean the panel faces last, since the rest of the work will dirty them. How to clean solar panels safely covers that part.
Where it is worst in Sydney
Pigeon pressure is heaviest in the older inner and eastern suburbs, where established flocks are well fed and roof stock is dense. Common mynas are widespread across the whole basin.
Coastal properties get a second problem on top of it: gulls, and salt exposure that accelerates the corrosion the droppings start.
Properties backing onto bushland tend to have less of a pigeon issue and more of a possum one, which needs a different approach entirely.
If the roof feeds a rainwater tank
Bird droppings on a catchment roof are a genuine water quality problem, not a cosmetic one. If the roof feeds a tank used for drinking, proofing the array is part of protecting the supply, and the tank needs to be disconnected during any cleaning work. We set this out in roof cleaning on tank-fed properties.
Getting it done
We handle the clearing, decontamination and panel cleaning side of this, and the gutter work that always comes with it — see solar panel cleaning.
For the mesh or skirt installation itself, use an installer who will put in writing that no fixing penetrates the panel frame or the roof. If they will not, find another one.
