Hearing Scratching in the Ceiling? What to Do About Rats and Mice This Winter

Hearing scratching in the ceiling during winter may be a sign that rats or mice have moved into the roof space, although birds, possums, insects and normal building movement can sometimes create similar sounds.

Rather than assuming the cause, look for other signs of rodent activity before deciding on the best course of action. During winter, roof spaces, wall cavities, garages and sheds can provide rats and mice with shelter and access to food, water and nesting material.

This guide explains what to look for, where to inspect safely, how to determine whether rats or mice may be present, and the different rodent-control options available for New Zealand homes and properties.

Why Rodents May Move Indoors During Winter

As temperatures drop, rats and mice may seek warmer, more sheltered places with access to food, water and nesting material.

Small gaps around rooflines, vents, pipes, foundations and subfloors may provide access to roof spaces and wall cavities. Garages, sheds and storage areas can also offer shelter, particularly where pet food, bird seed, grass seed, animal feed or other stored products are available.

Taking action early can help prevent a small rodent problem from becoming more established.

Common Signs of Rodent Activity

Scratching noises are one of the most common signs of rodents, particularly when the house is quiet at night. However, noise alone is not enough to confirm whether rats or mice are present.

Look for several signs together, including:

• Scratching, scurrying or gnawing sounds, especially after dark
• Droppings in roof spaces, cupboards, garages or sheds
• Chewed food packaging, boxes or stored items
• Gnaw marks on timber, plastic or electrical wiring
• Nesting material such as shredded insulation, cardboard, paper or fabric
• Greasy rub marks along walls or frequently used pathways
• Pets showing unusual interest in ceilings, cupboards or walls

If you notice several of these signs together, there is a greater likelihood that rodents are responsible.

Is It More Likely to Be a Rat or a Mouse?

Rats and mice can produce similar signs, but there are some general differences that may help you understand what you are dealing with.

Sign	Rats	Mice
Noise	Heavier movement, gnawing or thumping sounds	Lighter scratching and quicker movement
Droppings	Generally larger and thicker	Generally smaller and more slender
Damage	Larger gnaw marks and heavier damage	Smaller chewing marks and packaging damage
Common locations	Roof spaces, garages, sheds and subfloors	Cupboards, wall cavities, storage areas and kitchens

These are general indicators only. If you are unsure what is causing the activity, continue monitoring or seek advice from a pest-control professional.

Areas to Inspect Around Your Property

Roof Spaces and Ceiling Cavities

Roof spaces are one of the most common places for rodents to shelter during winter. Look for droppings, damaged insulation, nesting material and signs of movement around pipes, wiring and roof framing.

Only inspect roof spaces if it is safe to do so. Avoid standing on ceiling lining or unstable surfaces. If access is difficult or you are unsure, consider seeking professional assistance.

Wall Cavities

Scratching inside walls may indicate rodents travelling between rooms or nesting within insulation. Sound can travel through wall and ceiling cavities, so the source may not be directly above or beside where the noise is heard.

Garages

Detached garages are common around New Zealand homes and often contain grass seed, pet food, bird seed, tools and stored boxes that provide both food and shelter.

Sheds

Garden sheds and workshops may contain seed, compost additives, animal feed or stored materials that attract rodents during winter.

Around the Outside of the Home

Inspect vents, rooflines, drainpipes, doors, foundations and cladding for possible entry points. Trim overhanging trees and manage fallen fruit, compost, rubbish and other outdoor food sources that may encourage rodent activity.

What Should You Do If You Hear Scratching?

If you suspect rodents, avoid rushing into major repairs before confirming the source of the problem.

• Inspect for droppings, gnaw marks and nesting material
• Remove accessible food sources
• Store pet food, bird seed and animal feed in sealed containers
• Reduce clutter in garages and sheds
• Monitor for further activity

Avoid immediately sealing every suspected entry point if rodents are still active inside the building. Begin monitoring and control first, then complete proofing once there are no further signs of activity. If you are unsure, seek advice from a pest-control professional.

Choosing an Initial Rodent-Control Approach

Effective rodent management usually combines prevention with an appropriate control method. Pestrol’s range of rodent-control products includes electronic repellers, traps, bait stations and rodent bait for different situations.

Prevention

Reducing access to food, water and shelter remains the foundation of long-term rodent control.

• Seal accessible entry points once activity has stopped
• Store food securely
• Keep garages and sheds tidy
• Trim vegetation around buildings
• Regularly inspect roof spaces and storage areas

Electronic Rodent Repellers

Electronic rodent repellers may suit homeowners looking for an ongoing preventative measure in suitable indoor areas.

Products such as the Pestrol Rodent Free Max should always be installed and used according to the product instructions.

Repellers work best as part of a broader rodent-management plan rather than as a substitute for sanitation, proofing or other control methods where rodents are already active.

Rat and Mouse Traps

Rat traps and mouse traps provide a direct way to target confirmed rodent activity and can also help monitor whether rats or mice are still present.

Correct placement is important, particularly along walls or routes where droppings, gnawing or regular movement have been found.

Always follow the product instructions and position traps where children, pets and non-target animals cannot interfere with them.

Bait Stations and Rodent Bait

For some situations, bait stations and rodent bait may form part of a broader rodent-control programme.

Rodent bait should always be selected, positioned and maintained strictly in accordance with the product label. Where appropriate, use a suitable bait station and ensure bait cannot be accessed by children, pets, wildlife or other non-target animals.

Helping Prevent Rodents from Returning

Even after rodent activity has stopped, ongoing prevention is important.

• Inspect your home regularly for new entry points
• Store pet food, bird seed, grass seed and animal feed securely
• Keep garages, sheds and roof spaces organised
• Manage compost, rubbish and fallen fruit
• Trim plants and branches away from buildings
• Continue monitoring for fresh signs of rodent activity throughout winter

Removing one rat or mouse does not always confirm that the entire problem has been resolved, so continued monitoring is worthwhile.

When Should You Contact a Pest-Control Professional?

Professional assistance may be appropriate if:

• Rodent activity continues despite treatment
• You cannot safely inspect the affected area
• There are signs of a larger infestation
• Electrical wiring or building materials appear damaged
• The activity is in a food business, warehouse or other commercial premises
• You are unsure which control method is most appropriate

A pest-control professional can inspect the property, identify likely entry points and recommend a treatment plan for the specific situation.

Frequently Asked Questions

Why do I hear scratching in the ceiling mainly at night?

Rats and mice are generally most active at night when the home is quieter, making their movement easier to hear.

Can mice live in a roof space?

Yes. Mice can enter through small openings and may use roof spaces, insulation and wall cavities for shelter and nesting.

Should I seal holes as soon as I hear scratching?

Not always. Sealing entry points while rodents are still inside may trap them within the building. Begin monitoring and control first, then complete proofing once activity has stopped.

Are electronic rodent repellers enough on their own?

Electronic repellers may form part of an ongoing prevention strategy, but confirmed rodent activity may also require trapping, baiting, sanitation and proofing.

When should I contact a pest-control professional?

Professional advice is recommended if rodent activity continues, the affected area cannot be inspected safely, there are signs of significant damage, or the problem involves a food business or commercial premises.

Find the Right Rodent-Control Solution

Whether you are hearing scratching in the ceiling, noticing activity in the garage or trying to prevent rodents from entering your property this winter, Pestrol offers a range of practical rodent-control options for New Zealand homes and properties.

Browse Pestrol’s complete Rodent Control range to compare electronic repellers, rat and mouse traps, bait stations and rodent bait. Taking action early, removing food sources and continuing to monitor the area can help prevent a small problem from becoming more established.