The simple £1 test experts recommend to spot rat entry points this October

With the arrival of cooler temperatures in autumn, rats begin seeking warm, dry places to take shelter, often turning to homes as ideal hideouts. Pest control specialists advise that a straightforward test, taking just a few minutes, can help homeowners identify potential entry points for these rodents before a problem develops.

John Whiteley-Wilkson, Managing Director and pest expert at Acorn Environment Services, highlights the effectiveness of the ‘£1 coin test’ to spot vulnerable areas. “Most rat issues do not start because homeowners have done something wrong,” he explains. “Rodents are opportunistic and will always look for the easiest route indoors. Spending ten minutes performing the £1 coin test can highlight weak spots before they become a serious problem.”

Rats can squeeze through gaps approximately 15 to 20mm wide - about the diameter of a £1 coin. If a coin fits into any gap around your property, that space could be large enough for a rat to enter.

Mr Whiteley-Wilkson notes, “Many people are surprised at how small a space a rat can slip through. If a £1 coin fits into holes around external walls, air bricks, pipes, or door frames, these should be examined carefully and sealed where possible.”

Common areas to check include:

Around Pipes: Utility pipes penetrating the home often create gaps that may widen over time with the expansion and contraction of materials. These points are frequently overlooked, especially if concealed by bins, plants or outdoor storage.
Air Bricks and Vents: Damaged or uncovered air bricks and vents provide rodents easy access to wall cavities or underfloor spaces. While essential for ventilation, missing protective mesh or damage can make them vulnerable entry points.
Beneath Doors and Garage Entrances: Worn weather strips or ill-fitting garage doors can leave enough space for rats to squeeze underneath. Garage doors and side gates are recommended starting points for home inspections.
Sheds and Extensions: Rodents often establish themselves in outbuildings such as sheds and garages before moving on to the main house. Mr Whiteley-Wilkson points out that once rats are settled in these locations, they find moving into the property easier if openings exist.

In addition to sealing potential entry points, removing attractants is crucial. Reliable food sources such as fallen bird seed, overflowing bins, pet food left outside, and compost heaps can draw rodents near the home.

“Preventing entry is only part of the solution,” says Mr Whiteley-Wilkson. “If food is readily available outside, rats will keep returning and will eventually look for ways inside.”