Solar panel bird proofing

If you hear scratching above the ceiling at first light, or you are pulling twigs and dried droppings out of the gutter, something has moved in under the solar panels.

An array sits on frames about 10 to 15 cm above the roof. That gap is dry, warm, shaded and open on every side, which makes it the best nesting site on the building. Pigeons find it first, then starlings and sparrows.

The fix is a physical barrier around the edge of the array. Done properly, it goes on without a single hole in the panel frame or the roof.

What the birds actually do up there

A nesting pair is not the problem. The problem is what collects underneath them over a season: nesting material, feathers and a layer of droppings sitting directly on the roof sheet.

• Droppings are acidic. On Colorbond they eat through the coating and start the sheet rusting from the top down. On a tiled roof they break down the mortar in the ridge capping.
• Nesting material washes into valleys and gutters in heavy rain, blocks the outlet and backs water up under the tiles and into the eaves.
• Droppings baked onto the lower edge of a panel shade the cells behind them. A shaded cell works against the rest of the string and heats up, and that hot spot can take out the panel.
• Cabling, isolators and temperature sensors sit in the same cavity. Birds dislodge them and peck at the insulation.

None of this is visible from the ground, which is why most owners find it through the gutter or through the noise.

Mites, smell and sleep

Bird mites and lice live in the nest rather than on the bird, and they go looking for a host when the nest is abandoned. They travel through ceiling vents, downlight cutouts and the gap around the manhole. In warm weather the smell of an old nest comes through the same openings. The cooing and the scratching start before dawn and carry straight through a plasterboard ceiling.

Which birds you are allowed to move on

Feral pigeons, common starlings and house sparrows are introduced species and are not protected wildlife. Native birds are, under the Wildlife Act 1975, and they do occasionally use the same cavity. So the first job is to look at what is actually up there rather than assume.

Either way, nothing gets sealed in. Blocking a bird under a panel leaves you with a cruelty problem under the Prevention of Cruelty to Animals Act 1986, a smell you cannot reach, and mites with nowhere to go but inside. We check the cavity for live birds and dependent young before anything is closed off, and we use exclusion only: no poison, no traps.

How the mesh goes on

The barrier is steel mesh, galvanised or stainless, with an aperture small enough to keep pigeons and starlings out and open enough to let air move under the panels. It runs continuously around the perimeter of the array, including the corners, which is where a cheap job leaves a gap.

It is held on with purpose-made clips that grip the lip of the panel frame. That detail is the whole job:

• No drilling. A hole in the panel frame voids the manufacturer’s warranty, and it is not worth the twenty seconds it saves.
• No screws or fixings into the roof. Every penetration is a future leak, and on a tiled roof it cracks the tile.
• No adhesive. It lets go after a couple of Melbourne summers and takes the mesh with it.

Spikes are the other thing we get asked about. Under a panel they do not work: birds push past them, or drop enough nesting material on top to walk over the lot. Spikes belong on a ledge or a parapet, not on the edge of an array.

The order of work

Proofing a cavity that is already occupied, without clearing it first, is the most common mistake we are called back to fix. The sequence is:

• Inspect the cavity and identify what is nesting there.
• Move the birds on, then remove nests, droppings and debris, including whatever has washed into the gutters and valleys.
• Sanitise the area to deal with mites, lice and bacteria.
• Clean the panels themselves, since the droppings on the glass are what costs you output.
• Fit the mesh around the full perimeter and photograph it.

A single-storey house with a shallow pitch is a straightforward job. A two-storey townhouse, a steep gable or an apartment roof is not, and that is the point at which a ladder stops being an option.

Getting to the array

Where a ladder will not do it safely, we work off ropes from certified anchors or from an elevated work platform. Rope access gets us to the outer edges and the ridge without walking the roof, which matters on old terracotta where every step is a cracked tile.

Our crews have worked on ropes since 2013. Technicians are IRATA or ARAA certified and hold Working at Heights tickets. A Safe Work Method Statement is written for any fall risk over two metres, and we carry $20 million public liability. You get a written scope before the job and a photo report of the cleared cavity and the finished mesh after it.

What to ask before you accept a quote

Most of the difference between a job that lasts and one that fails in a year is in the detail, so ask:

• How is the mesh fixed - clips on the frame, or screws into the frame or the roof?
• Does the price include clearing and sanitising the cavity, or only fitting the mesh?
• Are the gutters and valleys cleared of what has washed down from the nest?
• How will the crew reach the far edge of the array, and what are they certified to do?
• Do I get photos of what was under there before it was closed up?

Send us the address and a few photos of the roof and we will tell you what the job involves.