Grey squirrels cause four kinds of damage, and they get more expensive in roughly that order. They gnaw electrical cable, which is the serious one because it is a fire risk. They gnaw structural and decorative timber, so soffits, fascias, barge boards, window frames and roof timbers, turning small gaps into permanent entrances. They tear up and compact loft insulation and foul it, along with cold water tanks, with urine and droppings. And outside they strip bark from trees, which can weaken and eventually kill established beech, oak and chestnut.
The reason squirrel damage is worth acting on earlier than most pest problems is that it does not level off. A rat or mouse population is limited by the food available to it. A squirrel in a roof void gnaws because its incisors grow continuously and have to be worn down, so the damage carries on at the same rate whether or not the animal is finding anything to eat, and it accumulates for as long as it has access. A loft that has had squirrels for two seasons looks nothing like one that has had them for a fortnight.
Cable damage is the one that matters most
Cable insulation happens to be close to ideal for a gnawing animal, being soft enough to work and firm enough to be satisfying, and squirrels strip it readily. Once the conductors are exposed you have the conditions for arcing, and arcing in a roof void surrounded by dry timber, dust and loose insulation is how this stops being a pest problem.
The warning signs are worth knowing because they rarely look electrical at first. Lighting circuits that trip intermittently, a residual current device that keeps going for no obvious reason, or a smell of hot plastic in an upstairs room are all worth investigating properly if there is any daytime activity overhead. We've found that homeowners tend to report the noise and the electrical fault as two separate problems weeks apart, and it is only when someone puts them together that the urgency becomes clear.
Timber and the building fabric
Squirrels do not so much find a way in as make one. A gap at a soffit joint, a lifted tile or a rotten section of fascia gets enlarged until it is comfortable, and the same animal will keep working at it. They gnaw soffits, fascias, barge boards, external window frames and door frames, and inside the void they will gnaw rafters, joists and any exposed timber they take an interest in. They also gnaw uPVC, so a plastic soffit is no defence.
The British Pest Control Association's guidance on grey squirrels makes the same point about damage to window frames, woodwork, doors and soffits, and it is consistent with what we see. Where it gets expensive is on the converted and period buildings, because the timber being chewed is original and the repair is a joinery job rather than a length of replacement board.
Insulation, water tanks and stored belongings
Loft insulation gets pulled about, compacted into runs and nesting material, and fouled with urine and droppings. Compacted insulation stops doing its job, so there is a running heating cost sitting underneath the more obvious damage, and fouled insulation has to be removed and replaced rather than cleaned.
Open cold water and header tanks are the part people find most unpleasant. The BPCA guidance notes contamination of cold water tanks with urine and droppings, and a squirrel that falls into a tank and cannot get out creates an immediate and serious problem with the water supply. A lid on the tank is a cheap piece of insurance in any loft that has ever had an animal in it. Anything stored up there in cardboard is fair game too, both as nesting material and as something to chew through.
Outside, the damage is to trees
Bark stripping is the damage most people miss because it does not happen where they are looking. Squirrels strip bark from beech, oak, chestnut and sycamore, particularly on younger, smoother stems, and a ring of stripped bark interrupts the tree's ability to move water and nutrients. A badly stripped tree may survive in a weakened state for years, or die back from the top down. They will also take bulbs, fruit and buds, empty a bird feeder daily, and gnaw at sheds, summerhouses and garden furniture.
Why it escalates rather than settles down
Grey squirrels breed twice in most years, broadly in late winter and again in summer, so a roof void that suits one animal tends to be occupied by more over time. They are also strongly site faithful, returning to a place that has worked before, which is why a loft that has been cleared but not proofed is usually reoccupied by the following season rather than left alone.
The seasonal pattern here is a push towards buildings as the weather turns in autumn, and the properties that see it most are the oast houses, barn conversions and period farm buildings around Tenterden, Canterbury and the Ashford villages. Those roofs have large open voids, a great deal of original timber and dozens of small irregular gaps, and the mature trees in those gardens usually provide the approach as well. From working with clients on that kind of building, the access point is very often a tree limb overhanging the roof rather than anything wrong with the building at all.
The law, and why you cannot simply move one on
Grey squirrels are an invasive non native species, and the legal position surprises people. Under the Wildlife and Countryside Act 1981 and the Invasive Alien Species (Enforcement and Permitting) Order 2019 it is an offence to release a grey squirrel once it has been caught, so anyone who traps one alive is legally obliged to dispatch it humanely. Defra's grey squirrel policy statement sets out the position and the reasoning, which is largely about protecting the remaining red squirrel population from squirrelpox.
The practical consequence is that catching one in a live trap and driving it to a wood is not a kind solution, it is an offence. That, plus the fact that the work happens at height, is why most people hand this one over.
Repairing the damage without closing the route is wasted money
The single most common thing we are called back to is a roof where someone has found the hole, patched it neatly, and been reoccupied within weeks.
In our experience, proofing the whole roofline in one visit works better than sealing the single hole they came in through because a squirrel that has already used a roof will work every other weak point along the same elevation within days of finding its usual way blocked. A one hole repair typically reopens a metre or so along inside a fortnight, and the second repair costs as much as doing it properly would have.
Sealing also has to happen at the right moment. Closing a void with an animal still inside is inhumane, and a trapped squirrel does a great deal of damage trying to get out, so removal and proofing are sequenced rather than done in one go. The same roofline logic that applies to protecting a loft from pests generally applies here, with the difference that squirrels need heavier gauge material than rodents and will test it.
When to call someone
Call if you hear heavy, purposeful movement overhead during daylight, which distinguishes squirrels from rats and mice straight away, or if you find gnawed cable, gnawed timber, disturbed insulation or droppings in the loft. Call sooner rather than later if there is any electrical symptom at all. Much of the groundwork for keeping rodents out in the first place also keeps squirrels out, with cutting back overhanging branches doing more than anything else.
We have been dealing with squirrels in roofs across Romney Marsh, Ashford, Tenterden, Canterbury, Folkestone, Hythe and the surrounding villages since 2008, with more than twenty years in the trade behind that. Squirrel work sits within our rodent control service, and we cover domestic, commercial and industrial property. If you have something moving about above the ceiling in the daytime, get in touch and we will take a look.
Cinque Ports Pest Control Ltd is a family run business based in Dymchurch, Romney Marsh. We are BPCA members, Kent County Council Trading Standards approved, TrustMark registered, SafeContractor approved and CRRU supporters.
