Pest Control
Mice in the loft? How to spot them, and stop them
Light scratching overhead after dark, small droppings by the insulation. How to confirm it is mice, how they are getting in, and how to stop it for good.
Light scratching above the ceiling at night, and small dark droppings by the loft hatch, usually mean one thing. Mice in the loft are one of the most common calls we take from October onwards. Here is how to confirm it, how they get in, and how to stop it.
The short version
- Mice move into lofts as the weather cools, looking for warmth, shelter and somewhere quiet to nest.
- The usual signs are scratching after dark, droppings, chewed boxes and shredded insulation.
- Removing the mice is half the job. Finding and closing the way in is what stops them coming back.
Why do mice love lofts?
A loft gives a mouse everything it needs: warmth rising from the house, insulation to nest in, shelter from predators and, in most homes, very little disturbance. Mice do not hibernate, so as the temperature drops in autumn they look for exactly this kind of space, and a loft that nobody visits can hold mice for weeks before anyone notices.
They do come down into the house for food. Kitchens, under-stairs cupboards and the spaces behind built-in appliances are often part of the same problem.
Signs of mice in the loft
- Noise after dark. Light, quick scratching or scurrying, often in short bursts, above ceilings or inside walls.
- Droppings. Small, dark and rod-shaped with pointed ends, about 3 to 6mm long, scattered along joists, by the hatch and near insulation.
- Gnawing. Chewed cardboard boxes, stored fabric, insulation and the sheathing on cables.
- Nests. Balls of shredded paper, fabric or insulation tucked into a sheltered corner.
- Smell. A stale, musky smell in an enclosed space, which comes from mouse urine.
Heavier, slower movement and much larger droppings point to rats instead, which need a different approach. Our guide on telling rats from mice in a loft covers the differences.
Are mice in the loft dangerous?
- Hygiene. Mice urinate as they move and leave droppings wherever they go. Their droppings and urine can carry bacteria such as salmonella, and they contaminate anything stored in the loft.
- Wiring. Mice gnaw constantly to keep their teeth in check. Chewed cable insulation is a fire risk, and it is one of the main reasons not to leave mice in a loft.
- Damage. Insulation gets flattened and fouled, and boxed belongings are chewed and soiled.
- Numbers. House mice breed quickly, with several litters a year, so a few mice in October can be a lot of mice by the new year.
How do mice get in?
A house mouse can get through a gap of about 6mm, roughly the width of a pencil. Common entry points into a loft include:
- gaps under roof tiles and at the eaves
- damaged or loose soffits and fascias
- gaps where pipes and cables pass through walls
- air bricks without mesh, and gaps around boiler flues
- cavity walls, which mice climb inside to reach the roof space
New houses are not immune. Service entries and cavity closers are often left with gaps big enough for a mouse.
What you can do
- Act early. A small problem is far easier to clear than an established one.
- Use snap traps rather than poison. For one or two mice, well-placed snap traps along the edges of the loft, against walls and beside joists, are effective and let you see what you have caught. Poison laid in a loft often means mice dying out of reach in walls and ceilings, with the smell that follows.
- Remove food. Do not store bird seed, pet food or any food in the loft, and keep kitchen food in sealed containers.
- Handle droppings safely. Wear gloves, dampen droppings with disinfectant before wiping them up, and never sweep or vacuum them dry.
Prevention tips
Once the mice have gone, close the way in. Seal gaps around pipes and cables, fit fine mesh over air bricks and roof vents without blocking the ventilation, repair soffits and eaves, and check the loft every few weeks through autumn and winter. Seal the gaps after the mice are cleared, not before, or you can trap them inside the house.
When to call us
Call us if the activity carries on after a week or two of trapping, if you are hearing it in several places, if you cannot get into the loft safely, or if you are not sure whether it is mice or rats. We find out what you have, treat it, show you where it is getting in and proof it. Our mouse control page explains the process.
More pest guides
The British mice identification guide
Britain has several kinds of mouse, but only a couple cause trouble indoors. How to tell a house mouse from a wood mouse, and why it changes what you do next.
Read the guide →Smells like trouble: dealing with dead rodents
A sour, sickly smell that moves from room to room is often a dead rodent in a wall or under a floor. How long it lasts, and how to deal with it safely.
Read the guide →Not sure what you're looking at?
Send us a photo or describe it. We will tell you what it is, whether it needs treating at all, and what it would cost, before anyone comes out.