How to Get Rid of Mice Under Floorboards (and in Lofts) – The Complete UK Guide

Hearing scratching beneath your feet at night can be unsettling. For many UK homeowners, discovering mice under floorboards or even in the loft is a common problem, especially in older houses with timber floors. Left untreated, these small intruders can cause damage to wiring, insulation, and food storage, not to mention the hygiene risks they pose.

This guide explains how to spot the signs of mice under floorboards, why they get there in the first place, how to remove them safely, and the best ways to keep them out for good.

Signs of Mice Under Floorboards or in Your Loft

Mice are elusive creatures, often nesting in hidden spaces like lofts, cavity walls, and floor voids. Because they prefer the dark, you may not see them directly, but there are clear signs you can look for.

Noises at Night

Scratching, scurrying, or squeaking sounds coming from beneath floorboards or overhead in the loft usually occur after dark, when mice are most active.

Droppings and Smells

Mouse droppings look like small black grains, around 3–6 mm long, and are often scattered along skirting boards or under cupboards. A strong, musky odour – similar to ammonia – can also indicate a hidden infestation.

Chewing and Damage

Mice gnaw constantly to keep their teeth short. Look for chewed skirting boards, frayed carpet edges, or even damage to electrical cables and insulation.

Nesting Materials

Shredded paper, fabric, or loft insulation clumped together are strong signs of a nearby nest.

How Do Mice Get Under Floorboards and Into Lofts?

Mice are flexible and determined animals. They can squeeze through gaps as small as 6 mm, which makes floorboards and lofts ideal hiding places.

Common Entry Points

• Gaps between floorboards or at the edges of skirting
• Openings around pipes or cables
• Ventilation grilles or poorly sealed air bricks
• Small cracks in walls, foundations, or door frames

Why Lofts Are Attractive

Lofts provide warmth, insulation for nesting, and often easy access to the rest of the house through pipework or voids in the walls. If you notice movement in the loft, it’s common for the same mice to move under the floors too.

Older Homes Are at Risk

Traditional timber-floor houses and period properties often have more gaps, making them particularly vulnerable to infestations.

The Risks of Ignoring a Mouse Infestation

Some homeowners hope mice will disappear on their own, but this rarely happens. In fact, the problem usually grows worse.

Health Risks

Mice spread bacteria and can contaminate food preparation areas with droppings and urine. Their presence can aggravate asthma and allergies.

Property Damage

Gnawed wiring creates a fire risk. Insulation can be shredded and ruined. Even floor timbers can be damaged over time.

Stress and Disruption

Noises at night and unpleasant smells can quickly become distressing. A small problem can escalate, costing far more to resolve later.

How to Get Rid of Mice Under Floorboards: DIY Methods

If you’ve identified signs of mice, it’s essential to act quickly. Here are proven steps homeowners can take.

Seal Entry Points

• Fill small gaps with wire wool packed tightly into place.
• Use a strong sealant or caulk around pipes and cables.
• For larger holes, consider metal mesh or expanding foam.

Blocking entry points is one of the most effective long-term solutions.

Use Traps

Snap traps remain one of the quickest ways to deal with a mouse. Bait them with peanut butter, chocolate, or seeds. Place traps near suspected entry points, close to walls, and in dark corners.

Humane traps can also be used if you prefer to release the mouse outdoors, though it’s important to relocate them far from your property.

Consider Baits and Poisons

Rodenticides can be effective but must be used with care. Always follow safety instructions and keep them away from pets and children. Because poisoned mice may die under floorboards and cause odours, this option requires caution.

Targeting the Loft

If mice are active in your loft:

• Seal gaps around the roofline and attic hatch.
• Store loft items in sealed containers rather than cardboard boxes.
• Place traps along common runways near insulation or beams.

When to Call in Professional Help

DIY methods can work for small infestations, but there are times when professional pest control is the safer option.

Signs You Need a Professional

• Persistent noise or droppings despite using traps
• Infestation in hard-to-reach places under floors or within walls
• Concerns about wiring damage or hygiene risks

What to Expect

Professionals will carry out a survey, identify entry points, and apply targeted treatments. Many companies also provide proofing services to prevent a repeat problem.

Costs

In the UK, treatment for a mouse infestation typically ranges from £150 to £300 depending on the size of the property and the extent of the problem.

Preventing Mice From Returning

Once you’ve removed mice from under your floorboards, prevention is the key to long-term peace of mind.

• Seal gaps – check skirting boards, pipes, vents, and door frames regularly.
• Store food properly – use sealed containers and avoid leaving crumbs or pet food out overnight.
• Manage bins – keep lids secure and move outdoor bins away from doors and vents.
• Reduce clutter – piles of cardboard or stored items in lofts attract nesting.
• Seasonal checks – autumn and winter are peak times for mice moving indoors, so inspect your home carefully during these months.

Frequently Asked Questions

Conclusion

Discovering mice under floorboards or in the loft can feel overwhelming, but the problem is manageable if dealt with early. By recognising the signs, sealing entry points, using traps or baits effectively, and taking steps to prevent re-entry, you can protect your home and your peace of mind.

If you suspect a larger infestation or ongoing damage, don’t hesitate to call a professional for support. Acting quickly saves money, prevents stress, and ensures your home stays mouse-free.