Squirrel Infestation Signs

Scratching noises around dawn, damaged insulation, and holes around the roofline are some of the clearest squirrel infestation signs. Find out what these indicators can mean, the type of damage squirrels may cause, and what steps to take when you suspect an infestation.

Grey squirrels are a common source of unexplained loft noises in UK properties located near woodland, parks, and gardens containing mature trees. This guide explains the main signs associated with a grey squirrel infestation, including the noises they can create inside roof spaces and the physical evidence they may leave behind. It also looks at how squirrel activity can be distinguished from rats or mice when the cause of the disturbance is unclear.

For many property owners, sound is the first indication that squirrels may have entered a building. Their movement across timber ceilings can create a recognisable noise, particularly during the early morning or late afternoon. However, by the point when these sounds become noticeable enough to investigate, squirrels may already have occupied the loft for several weeks. During this time, they can damage insulation, cables, and other parts of the building. Knowing which additional signs to look for, whether during a roof inspection or when accessing the loft for another reason, can help identify squirrel activity sooner and potentially reduce repair costs.

Sounds: What Squirrels Sound Like in a Loft

Grey squirrels can produce a recognisable range of noises when they are active inside roof voids. One of the most noticeable sounds is the rapid movement of an animal travelling across ceiling joists. Compared with a mouse, the movement is heavier and more forceful, often creating a repeated thudding sound as the squirrel moves from one joist to another. Activity is generally most noticeable during the two main periods of the day, around two to three hours after dawn, commonly between 6am and 9am, and approximately two to three hours before dusk.

Chewing noises can also indicate squirrel activity. Their gnawing tends to be continuous and rhythmic when they are working on a hard surface. Grey squirrel chewing is usually deeper and more powerful than mouse gnawing. Unlike mice, which are often active and gnaw during the night, squirrels are primarily active during daylight hours. Scratching concentrated in one particular location may also be significant, especially when it occurs near an access point or an area where a drey is being built.

Occasionally, vocal sounds may also be heard from within a property. Grey squirrels can make sharp, repetitive barking or alarm calls. This sound is more commonly heard outside, although it can sometimes be audible indoors when squirrels are involved in territorial activity around the roof. A single squirrel may create relatively little noise compared with a breeding female caring for young, as the latter may travel regularly between the drey and outdoor feeding areas.

Grey squirrels are mainly active during daylight, so persistent loft noises that occur predominantly at night are more likely to involve rats or mice. Squirrel movement generally sounds heavier than the quick, light movements of mice and tends to be more rapid and bounding than the slower movements associated with rats. The time of day when the noise occurs can therefore be a useful initial clue when trying to determine which animal is responsible.

Physical Evidence in the Loft

Grey squirrel droppings are generally cylindrical with slightly tapered ends. They are usually around 8 to 12 millimetres long and approximately 4 to 5 millimetres in diameter. Fresh droppings tend to be medium to dark brown, while older droppings become paler and more crumbly as they dry. They can easily be mistaken for rat droppings because the two are similar in size and shape. However, squirrel droppings are generally lighter in colour and have a less noticeable odour. Mouse droppings are much smaller, usually measuring around 3 to 5 millimetres, and tend to have more pointed ends.

A grey squirrel drey inside a loft can be quite distinctive. It may consist of a substantial, roughly rounded mass of damaged loft insulation, including glass fibre or mineral wool pulled apart into loose strands. Squirrels may also incorporate bark, leaves, cardboard, fabric, paper, and other soft materials available within the loft. Dreys are commonly constructed in corners or against walls and may measure approximately 20 to 60 centimetres across. A drey being used by a female with young may be noticeably larger and more compact.

A grey squirrel drey in a loft space can destroy an area of glass fibre insulation equivalent to several square metres within a single breeding season, as the animal gathers and compacts material for the nest.

— British Pest Control Association (BPCA) Technical Guidance, 2021

Gnaw Damage and Entry Point Evidence

Grey squirrel gnawing can leave marks that are larger and deeper than those produced by mice. Their tooth marks may also have a rougher, more chiselled appearance compared with the finer marks typically associated with rats. In lofts, squirrels may chew timber roof structures, particularly around areas where cables are positioned. They may also damage PVC coverings around electrical cables, which can present a particularly serious concern. Other potential targets include insulation around plastic water pipes and hard materials that squirrels repeatedly gnaw at to keep their incisors at an appropriate length.

Signs around external access points can include fresh gnaw marks on fascia boards and soffits near the roofline. Damaged or displaced roof tiles may leave gaps large enough for squirrels to enter, while compressed dirt or traces of fur around the edges of openings can indicate repeated use. Scratching may also be visible on nearby paintwork or render below an entry point. Frequently used squirrel access points can develop a darker, worn appearance around the edges as oils from the animal's body accumulate through repeated entry and exit.

External and Garden Signs

Signs of squirrel activity in the garden may occur alongside evidence of an infestation within the building. These can include sections of tree bark stripped away in a spiral pattern around trunks or branches, particularly on smooth-barked species such as beech and sycamore. Other indicators can include shallow holes in lawns or flower beds where squirrels have buried or recovered nuts, damaged bird feeders, and squirrels seen travelling along roofs or disappearing beneath the eaves.

Regular sightings of squirrels running along the roof or gutters may suggest that they are investigating or using an opening in the roof structure. When a squirrel disappears beneath the eaves and does not quickly return, this can indicate that it has found an established route into the building and may be accessing the loft rather than simply moving across the roof surface.

Confirming the Species and Getting Professional Assessment

The combination of daytime noise, a substantial drey, cylindrical droppings of 8 to 12 millimetres, and external entry evidence strongly indicates grey squirrel rather than rat or mouse activity. However, mixed infestations — grey squirrels and rats simultaneously using the same roof void — are not uncommon in properties with multiple access points, and both species may be present without either being immediately obvious.

Professional pest controllers in Sheffield and South Yorkshire carry out systematic loft inspections that identify all species present, locate all entry points, assess the extent of damage, and determine the appropriate control programme. Early professional assessment means control work can begin before a single pair of squirrels becomes an established breeding colony — significantly reducing both the cost of the programme and the extent of repair work required afterwards.

Frequently Asked Questions

What do grey squirrels sound like in a loft?

Grey squirrels in a loft produce a heavy, rapid bounding movement across ceiling joists — a characteristic thud-thud pattern that is heavier than mice and faster than rats. Activity is concentrated at dawn and late afternoon. Persistent daytime gnawing on timber or cables is also common. If loft noise occurs primarily at night, rats or mice are more likely than squirrels, which are diurnal animals.

What do grey squirrel droppings look like?

Grey squirrel droppings are cylindrical, slightly tapered at both ends, 8 to 12 millimetres long, and 4 to 5 millimetres in diameter. Fresh droppings are medium to dark brown; dried droppings become lighter and more crumbly. They are similar in size to rat droppings but typically lighter in colour and less pungent. Mouse droppings are much smaller (3–5mm) with more sharply pointed ends.

How do I tell if squirrels or rats are in my loft?

The key differences are timing and movement patterns. Squirrels are active during daylight hours — noise from squirrels is concentrated around dawn and late afternoon. Rats are primarily nocturnal, with most activity after dark. Squirrel movement is fast and bounding; rat movement tends to be slower and more cautious. Squirrel droppings are lighter in colour than rat droppings and have less odour. A pest controller can confirm the species from inspection.

What does a squirrel nest look like in a loft?

A grey squirrel drey in a loft is a substantial, roughly spherical pile of torn loft insulation, bark strips, leaves, and soft materials collected from storage. It is typically 20 to 60 centimetres in diameter and is positioned in a corner or against a wall. A breeding drey used by a nursing female will be larger and more densely packed. It is much larger than a mouse's nest and more structured than a rat's nest.

What are the signs of squirrels getting into a roof?

External signs of roof entry include: fresh gnaw marks on timber fascia or soffit boards at the roofline; gaps under displaced or broken roof tiles; dark worn patches at gap edges where the squirrel has repeatedly passed through; and squirrels observed running along the roofline and disappearing under the eaves. Internally, a combination of loft noise, droppings, nesting material, and cable or insulation damage confirms entry.

What damage do squirrels cause to electrical cables?

Grey squirrels gnaw on PVC electrical cable insulation — not because they eat it, but because gnawing is a constant biological need driven by continuously growing incisor teeth. Gnawing strips the insulation from cables, exposing the live conductor underneath. Damaged cables in a loft space represent a genuine fire risk. Any electrical cables running through a loft space with confirmed squirrel activity should be assessed by a qualified electrician before the space is re-insulated.

How quickly should I act if I suspect squirrels in my loft?

Act as soon as you suspect activity. Grey squirrels breed twice a year, and a single pair that gains access in late summer can establish a breeding colony by the following spring. Early action — professional inspection, trapping, and proofing — costs significantly less than resolving a multi-animal infestation with an established drey and extensive cable or insulation damage.

Contact a pest controller for a survey when you first notice the signs rather than waiting to confirm the problem with certainty.