Rats under decking: signs, control and prevention

Signs that rats may be using the space

Look for droppings on nearby sheltered edges, worn routes, gnawed material and burrow entrances beside the deck. Repeated footage of rats entering the same gap is stronger evidence than one unexplained rustle. A smell alone is not enough to identify the animal or locate a nest.

Photograph from above or outside the structure without pushing a camera, hand or tool into an unknown space. Keep children and pets away from entrances. Note whether activity leads towards bins, a shed or the house. If you cannot see below the boards safely, that is a reason to arrange an inspection, not to crawl underneath or start dismantling a deck without checking its condition.

Why decking can attract rats

The covered void offers shelter from disturbance, especially when the edges are partly enclosed and the space is difficult to inspect. Nearby food can make that shelter more useful. Spilled seed, pet food, poorly closed bins and edible waste in a compost area all deserve attention.

Decking itself is not necessarily the original cause. Rodents may be travelling from an adjacent garden, a shared waste area or a defect elsewhere on the property. Treat the deck as one part of the site. Clearing your own food sources and sharing factual observations with neighbours can be more effective than repeatedly disturbing the same entrance while leaving the reason for the visits unchanged.

Remove food without creating another feeding point

Start with the area around the deck and work outwards. Clear food after outdoor meals, clean greasy barbecue residue when safe and collect fallen fruit where practical. Check that bin lids close properly and that waste is not sitting in split bags beside them.

• Store bird seed and pet food in robust, tightly closed containers.
• Clear spilled seed below feeders and review feeding if rats keep returning.
• Bring pet bowls in after meals.
• Avoid leaving edible scraps in open compost.
• Report overflowing communal bins to the responsible organisation.

Do not move a feeding station just a short distance away and assume the problem is solved. If rats have a reliable food supply elsewhere, coordinate changes with the people responsible for that area.

Inspect the deck without disturbing wildlife

Other animals may shelter under a deck. Do not assume an entrance belongs to rats, and do not block it simply because you dislike having wildlife close to the house. A competent inspection should consider the likely species, signs of nesting and the safest way to proceed.

Avoid smoke, flooding, fuel, strong chemicals or attempts to flush animals out with a hose. These methods can cause harm and damage without resolving access. Keep dogs from digging at the edges. If boards need lifting, use someone who can assess the structure and access safely. Tell the controller about pets, ponds, visiting wildlife and any earlier treatment so the plan accounts for the whole garden.

Why sealing the edges comes later

Mesh and edging can help exclude rodents when properly specified and fitted, but closing an occupied void can leave animals trapped. An incomplete barrier may simply divert them to another opening or towards the house. Agree the sequence of control, checking and final exclusion before ordering repairs.

The right detail depends on the deck, ground levels and nearby structures. A contractor should consider gnaw-resistant materials, secure fixings and vulnerable junctions rather than attaching flimsy mesh to one visible side. Ventilation, drainage and future inspection access still matter. Ask how the work will cope with movement, soil settlement and maintenance; a hidden gap behind a step can undermine otherwise careful edging.

Check whether activity extends towards the house

Inspect accessible air-brick surrounds, door thresholds and pipe entries near the deck without covering essential openings. Look indoors for fresh droppings or damage near the corresponding wall. If activity is suspected inside, tell the pest controller immediately so the garden and building can be assessed together.

Do not cover air bricks with solid panels or fill every cavity with foam. Ventilation protects the building, and inappropriate repairs can cause separate problems. Ask for purpose-designed, properly fitted protection where suitable. A suspected drainage defect also needs the right investigation rather than a guessed repair. If you rent or live in a managed development, notify the responsible party and provide photographs before structural work is arranged.

Cleaning around decking and contaminated items

Avoid brushing dry droppings through the gaps or using a pressure washer as your first response to contamination. These actions can spread dirty material and make it harder to control where it goes. Keep the area out of use while you decide what can be cleaned safely.

For a small accessible patch, wear gloves and use a suitable disinfectant according to its instructions before careful removal. Check surface compatibility, particularly on treated wood and near plants, drains or ponds. Extensive contamination beneath boards may need professional cleaning advice. Protect broken skin and wash hands afterwards. If you become unwell after possible contact with rat urine or contaminated water, seek medical advice and explain the exposure; the NHS has guidance on leptospirosis.

Where MintGuard helps, and where it does not

MintGuard is a repellent made from pressed peppermint, clove and castor oil balls. It does not clear an established infestation beneath decking. Open, wet and inaccessible spaces are poor places for loose scent products: you need a suitable dry position where the product can be checked, retrieved and kept away from children and animals.

One pack of 12 balls is £39, with bundles at £69 for two, £89 for three and £109 for four. Each ball lasts 30–60 days. MintGuard is sold only on mintguard.co.uk with a 90-day money-back guarantee. Consider it only as a supporting deterrent in suitable locations after the main problem is addressed. Do not throw balls through decking gaps or treat scent as a substitute for food control and exclusion.

When to call the council or a pest controller

Get professional help for repeated rat activity, a suspected nest, burrows you cannot assess or signs extending indoors. Ask for an inspection-led plan that includes food sources, treatment if needed, follow-up and a clear point when exclusion can be completed. Find out whether decking access or repairs require a separate contractor.

Your council may offer pest services or advice, and GOV.UK directs you to local reporting arrangements. Charges and availability vary. Shared waste or drainage issues may need a different team. Glue traps have been illegal for the public to use on rodents in England since 31 July 2024; restricted professional licences do not authorise household use. For other UK nations, check the applicable rules rather than assuming English licensing applies everywhere.

Common questions

Sources

• GOV.UK – Report a pest problem
• NHS – Leptospirosis
• GOV.UK – Glue trap licences