So the British Pest Control Association (BPCA) is urging people to take preventative measures and has issued an online guide and video with advice on what to do.
Pest controllers get thousands of call-outs every year due to the damage squirrels can cause and the noises they make at night.
Figures from BPCA suggest people have more problems with squirrels during the autumn when they are looking for food and shelter.
Dee Ward-Thompson, BPCA technical manager, said: “Squirrels can be an incredibly destructive and distressing pest to have in your home or workplace.
“Grey squirrels can cause damage when they enter roof spaces of houses and buildings. They gnaw on woodwork and ceilings, strip insulation from electrical wires, tear up fibreglass insulation and can contaminate cold water tanks and attic space with urine and droppings.
“People also report sleep issues due to the loud noises they make at night while they’re scuttling around the attic.”
The BPCA recommends squirrel-proofing your home or business, rather than trying to deal with an infestation.
Dee added: “Prevention is always better than cure.
“Block the gaps and entrance holes with tightly wedged mesh or metal plates, wherever possible. A pest control professional should be able to help you with this.
“You can trim tree branches that overhang your roof, remove items stacked against the side of the building and seal all entry points.”
For more advice about proofing your home or business against grey squirrels, visit bpca.org.uk/squirrels
And to find a BPCA member in your local area visit bpca.org.uk/find.