Solar Panel Bird Proofing

The gap nobody designs for

An on-roof array sits somewhere between eight and fifteen centimetres above the tiles. That gap exists for a good reason — it lets air move behind the panels and keeps them cooler, which keeps output up.

It also creates a long, dry, sheltered cavity with a warm ceiling, roughly the dimensions of a nesting box, running the full width of the array. Feral pigeons find it quickly. Once they are established, the array becomes a colony rather than a nest.

What it costs you

The mess is the visible part, and it is unpleasant. The rest is worse.

• Blocked airflow. Nesting material packed behind the panels stops the ventilation the gap was there to provide. Warmer cells produce less.
• Corrosion. Guano is acidic. Over time it attacks the anodising on frames and rails, the coating on fixings, the panel backsheet and the roof covering itself.
• Blocked gutters. Straw, twigs and droppings wash down and pack into the gutter below, which then overflows onto the wall.
• Cable damage. DC cable clipped under the array is at beak height. Pecked insulation leads to earth faults, a derating inverter, or an open string. This is a slow failure that usually presents years later as unexplained underperformance.
• Mites and smell. Nesting debris brings both, and in a bungalow or a dormer that is a problem inside the house as well as on it.

Clearing before proofing

Sealing a mesh around an array full of nesting material achieves nothing except trapping it in place. Clearance comes first.

The underside is cleared of nesting material, feathers, eggshell and droppings, which are bagged and disposed of properly rather than swept into the gutter. The area is disinfected. The gutters below are checked and cleared where debris has collected. While the perimeter is open we look at the cabling for peck damage and at the fixings for corrosion, and photograph anything that needs attention.

Nesting birds and the law

Wild birds and their nests are protected while in use or being built. That is not a technicality we work around; it means an array with an active nest is not proofed until the young have fledged.

We inspect before quoting, and we tell you what we find. Autumn and winter are the straightforward times for this work. If you call us in May and there are birds in there, the honest answer is that we will book you in for later, and clearing the gutter in the meantime is the practical interim step.

The mesh

The material is galvanised steel mesh with a PVC coating, with an aperture small enough to exclude a pigeon and to stop it getting a foothold. Uncoated wire corrodes at the cut ends; plastic-only mesh becomes brittle in UV and fails within a few years.

It is fixed with stainless steel clips that grip the panel frame and hold the mesh down against the tile line. Nothing is drilled — not the roof, and certainly not the panel frame, where a hole can breach the module seal and invalidate its warranty.

The perimeter is closed on every side that can be reached. Where an array runs to a ridge or into a valley, some sides may be inaccessible or already closed by the geometry, and we will tell you which those are rather than implying a complete seal that has not been achieved.

Fitted at the same time as a new installation, proofing costs considerably less than it does as a separate visit later, because the access is already there.