How to Get Rid of Woodlice in the House: UK Guide

Here is how to get rid of woodlice in most homes. Sweep or vacuum up the ones you can see and put them outside. Find the damp they are using, and fix it. Close the gaps at floor level and around doors. Then move whatever is sheltering them away from the outside wall. Clackmannanshire Council gives the same order, and says that once condensation or dampness is fixed the woodlice should eventually disappear.

Woodlice are harmless, and we do not think most households should pay anyone to spray for them. They are a symptom. Spray a line of them and the next ones walk in over it a week later, because the damp shelter that drew them is still there. The useful question is not what kills woodlice. It is what they are telling you about the house.

Most of the time the message is minor: a heap of pots by the back door, or a worn seal under it. Sometimes it is worth acting on: a slow leak inside a kitchen unit, a blocked air brick, or soil built up against a wall. Use the table below to decide how much effort your situation deserves.

Woodlice come inside for two reasons: cold outside, or damp inside. Darlington Borough Council says they mostly enter in winter and early spring, while Clackmannanshire Council says cold autumn and winter weather drives them in. Both agree they are looking for shelter. Darlington adds that they are not coming in to breed, but that a colony close to an entrance makes indoor sightings more likely.

That last point explains most repeat cases. A woodlouse does not plan a route into your home. It walks at night, looking for somewhere dark and damp, and if the nearest such place is behind your skirting board, it ends up in your hallway in the morning. Clackmannanshire names vegetation piled up outside as an encouragement. Large numbers indoors, it adds, can also signal high moisture from condensation or dampness.

So think of two separate problems. The source is the colony outside, or the damp pocket that keeps them alive. The route is the gap that lets them through. You need to deal with both, and the source matters more, because no one can seal an older house perfectly. The drawing below shows how the two connect in a typical London terrace with a timber ground floor.

Woodlice are not insects. The Wildlife Trusts describe them as land crustaceans, closer to crabs and shrimps, and Clackmannanshire Council gives the same family tree. The Natural History Museum groups them as crustaceans in its classification teaching material, and describes giant ocean isopods as their relatives. That ancestry is the reason they behave as they do. Their bodies never fully adapted to dry air.

This matters for practical reasons. Darlington Borough Council says that in warm, dry rooms they lose too much water and die within about a day, although they can last for several days under kitchen and bathroom sinks if they have food. A 2018 study in ZooKeys shows how much species vary. At about 30% humidity for six hours, one species lost all its test animals while the pill woodlouse lost none, and the authors link survival to a thicker shell and a larger body. The test did not include every UK house visitor, but it suggests that the round, rolling kind copes best in a drier room.

As for food, the RHS calls woodlice detritivores that mainly eat damp, decomposing plant material. Darlington adds dead insects and fungi, and the Wildlife Trusts add dead animals, and mention pill woodlice climbing walls at night to find mildew and rotting plants. Indoors, that means they are not after your food cupboard. They are after mould, rotting timber and the dead leaves that have blown under a door. Bare, clean, dry surfaces give them nothing.

Britain has about 30 species according to the RHS and the Wildlife Trusts, and about 35 according to Clackmannanshire. The RHS names four common garden groups: Armadillidium, Oniscus, Philoscia and Porcellio. You do not need to tell them apart, because the advice is the same for all of them.

A woodlouse is grey or brown, oval and domed, with overlapping plates and seven pairs of legs. Sizes vary by source. The RHS says up to 1 cm, Clackmannanshire about 15 mm, and the Wildlife Trusts 1.1 to 1.8 cm for the pill woodlouse. Use the table to rule out the usual lookalikes, because several of them do need a different response.

Woodlice themselves are harmless. Iowa State University says they do not bite, sting or damage furnishings, and Darlington says they are harmless and do not damage wood, despite the name. No source we read links them with disease. The real health question is the damp. GOV.UK says damp and mould are a particular risk for people with asthma, COPD or other lung or heart conditions, those with weakened immune systems, children, older people and pregnant women. If someone at home is in one of those groups and there is mould alongside the woodlice, treat the damp as a priority, and speak to a GP about any symptoms.

If the table rules out a woodlouse, go to the guide that fits: silverfish, carpet beetles, bed bugs or cockroaches. Still unsure? Try our guide to small brown bugs in the house.

Where you find them is your best clue, so note the spot before you sweep. Write down the room, the wall and the time of day for a week. Look at night with a torch too, because they are active in the dark and hide by day. Then use the route map below, and start with the cheapest check first.

GOV.UK sorts household damp into four kinds, and each leaves a different trail. Condensation forms on cold surfaces such as window frames, wall corners and behind furniture, and it is the most common. Penetrating damp comes in from outside through defects in walls, roofs, windows or floors. Rising damp comes up from the ground and is usually found in older properties, and GOV.UK warns that it is often misdiagnosed. Traumatic damp means leaks: burst or weeping pipes, overflowing baths and sinks.

A week of woodlice records plus a simple look at each of those four will usually tell you what you have. A cheap hygrometer helps if you suspect condensation, and our silverfish guide explains how to read one. If you are seeing silverfish in the same place, take that as a second vote for moisture.

Many older London houses have suspended timber floors, with a shallow space under the boards. An air brick is the small grid low on the outside wall that feeds that space. GOV.UK's guide to retrofitting these floors says outside air can and should flow beneath them, and that free-flowing air helps keep the floor construction healthy. If you see the same woodlice along the skirting of every ground-floor room, this space is the place to think about.

Check each air brick you can find, on every side of the house. That GOV.UK guide warns that later work such as new pavements, decking, soft landscaping or access ramps can obstruct them. It says raised soil should be carefully reduced to restore the flow, and that where that is not possible, a telescopic vent may solve it. Clear leaves, ivy and dirt from the grid with a stiff brush. Move anything stacked in front. Bath and North East Somerset Council gives the same advice to anyone insulating a floor: keep air bricks unobstructed.

Do not block an air brick to stop woodlice. It feels logical, and it is the one mistake in this guide that can cost real money, because still, damp air under a timber floor raises the risk of rot and decay. The same applies to expanding foam, tape and plastic covers. If you need a barrier against mice as well, the mesh must not choke the airflow, so read our mouse guide and ask for help with the detail.

Next, find the damp-proof course. Epping Forest District Council describes it as usually a black or grey line between the bottom brick courses. RICS says a path should sit at least two bricks, or 150mm, below it, and Cheshire East Council and Epping Forest give the same figure for ground levels. Soil, a raised bed or a patio above that line gives water a way round the barrier, and gives woodlice a damp ladder to the brickwork. RICS also points out that rain splashing off hard paving can wet the wall above the line, and that mortar over the course can bridge it.

That order of checks can save you a large bill. Epping Forest says failure of the damp-proof course itself is rare, and in RICS's bridged example the course has not failed and does not need replacing. So before anyone sells you injection treatment, lower the soil, clear the vents, and fix the gutter.

Once you know the source, this is a weekend job for most homes. Work through these steps in order. There is no point sealing a skirting until the leak behind it has been fixed, because sealing traps the wet in.

You cannot, and should not, clear woodlice from a garden. The RHS calls them a vital part of garden biodiversity, and says they recycle nutrients. Gardeners' World says there is no need to control them outside because they are not a pest. They also feed shrews, toads, centipedes, some spiders and ground beetles. What you can do is make the strip beside the house less attractive.

Think of it as a dry zone, roughly a metre wide, around the walls. That width is our suggestion, not a rule from any source. North Lanarkshire Council lists what to shift: leaves, grass clippings, mulch, wood, boards and stones near buildings. Move compost bins and log stores to the far end of the garden, where woodlice can do their job. Which? adds that sweeping where pots are kept, and removing old pots and seed trays, helps, and that clearing debris also reduces slugs and snails.

Timing helps. The drawing below shows why autumn is the moment to do this. Adults reach full size by late summer and then look for somewhere to spend the winter, which is exactly when leaf fall builds up against your wall. Clear the strip in October and you remove the shelter just before the indoor season begins. Our gardening team can clear back overgrown beds and borders if the job is too large to do yourself.

One warning on what you plant. Ground cover and climbers against a wall hold moisture and hide air bricks, so cut them back from the brickwork. Gardeners' World points out that removing habitat also removes ladybirds and ground beetles, so only clear the strip by the house and leave the rest of the garden alone.

Tip a pot and find woodlice underneath? That is normal. A pot gives them all they want: dark, damp, and bits of rotting leaf. Gardeners' World is clear that a large group under a container is not an infestation and does not mean the plant is being damaged. The RHS lists flower pots with logs and stones as a usual hiding place. For pots out in the garden, the best action is none at all.

Pots against the house are different, because they are also on the doorstep. Darlington Borough Council specifically mentions flower pots when it talks about removing shelter near the home. Move them a short distance from the wall and away from the back door, and stand them on pot feet or a slatted rack, so the base can dry. Sweep the spot where they stood. Empty saucers after rain, and throw out soggy old compost bags and stacked empty pots.

Indoor plants are a smaller version of the same thing. If you bring a pot in for winter, lift it first, and check under the rim and the drainage holes. Woodlice brought in on a tray will not last long in a warm room, but an overwatered plant on a damp saucer can keep a few alive. Water less over winter, empty the saucer and let the top of the compost dry out. If you find tiny pale jumping creatures in the compost, they are a different animal, and our guide to tiny black bugs in the house may help.

If you want to know how many you have, lay a damp piece of cardboard or an upturned pot by the wall overnight, then lift it in the morning. Empty what you find at the far end of the garden. We found no trial showing that this reduces numbers, so treat it as a survey more than a cure.

Rarely. The RHS says they seldom harm healthy plants, occasionally taking very soft tissue such as seedlings and sometimes strawberry fruits, and that they often get the blame for damage done by slugs, caterpillars or plain rot. Holes in tougher leaves are not theirs. Gardeners' World says they are far more likely to be on rotting fruit such as windfall apples.

Which? Gardening goes somewhat further. It lists seedlings, bedding plants, peas, beans, carrots, cucumbers, strawberries and tomatoes as things they can harm, and says that problems are more likely in greenhouses, which is where sources differ. The RHS treats them as abundant and largely beneficial in healthy greenhouses. Both can be right. An established tomato plant will not notice them. A tray of newly germinated seedlings on a damp greenhouse floor might.

Which? adds a useful test. They usually enlarge wounds made by slugs or wireworms in potatoes and bulbs, and cannot break into undamaged ones. If you find woodlice inside a hollow, something else got there first. Look for slime trails, which mean slugs or snails, and for damage to firm, older tissue, which points to other pests. If slugs are the real problem at scale, see our slug control page.

To protect seedlings, raise trays off the floor on staging, keep the greenhouse floor swept and clear of old pots and dead leaves, ventilate on mild days, and water in the morning so surfaces dry by night. Our recommendation is not to spray. Young plants can be protected by routine, and the woodlice in the compost below are helping you.

The internet recommends a long list of natural deterrents. We looked for evidence on each, and the honest summary is that very little has been tested on woodlice. The best natural method is the dull one: remove the moisture, because woodlice dry out and die without help from you.

The nearest thing to a real test is a 2025 paper in Biosystems Diversity. It put a woodlouse, Porcellio laevis, into a small T-shaped chamber for three minutes with 20 aromatic plant materials. Peppermint and tea tree oils acted as repellents. Coffee gave mixed results, both attracting and deterring. That is useful science, but three minutes in a lab tells you nothing about a wet wall over a winter. A student project at McCook Community College in the US found that the amounts of diatomaceous earth tested did not significantly cut pillbug damage to soybean sprouts, and the author stressed how small the study was.

If you still want to try a home remedy outside, note what HSE says. Some home-made remedies, such as coffee grounds, generally fall outside pesticide rules when used in your own garden, but that does not make them automatically safe or legal in every case. Do not mix your own insecticide. And keep in mind that a remedy which appears to work may just be coinciding with a dry week.

Almost never in a house. Iowa State University says insecticides are optional and not always needed. Clackmannanshire Council calls a residual dust or spray barrier a last resort. Darlington Borough Council limits it to cracks where woodlice hide, and to damp areas that cannot be properly dried. That last phrase is the only case we think makes sense: a cellar or sub-floor area that will stay damp however well you maintain it, with woodlice regularly coming up from it.

If you do use one, buy a product labelled for crawling insects and sold for general public use. HSE says everyone who uses a biocide is responsible for using it correctly, that you should first consider non-chemical options such as sealing entry points and keeping the area clean and dry, and that the label decides where, how much and who may use it. Keep it away from children, pets, food surfaces and fish tanks. Never pour the leftovers down a sink or drain.

Do not spray across the whole floor, and do not use products on plants or in pots unless the label says that you can. A garden barrier can also kill the ground beetles and spiders that are eating your woodlice, and will not stop new arrivals for long. Fix the damp, and you will not need any of this. For the wider picture on what treatments can and cannot do, see our pest control services.

Most of the checks above are safe to do yourself. Stop and get someone qualified when the problem is beyond a clean, a seal or a clear-out. Who you need depends on what you found, and in most of these cases that person is not a pest controller.

If you are told you have rising damp, ask how that was established. GOV.UK says it is often misdiagnosed and that chemical testing is the best way to confirm it. An independent surveyor who is not selling the repair can be worth paying for, particularly in a listed or period home. RICS publishes consumer guides on damp, which are a useful place to start.

Mould needs care too. Treat what caused it, and do not simply paint over it. Keep a dated photo before you clean. Our cleaning services can help with a general clean after repairs, but a clean does not fix the cause.

If you rent, do not spend money on damp repairs before you have told your landlord. Woodlice on their own can be left to the tenant. Waverley Borough Council, for example, tells its own council tenants that they must deal with woodlice in the home themselves, so read your tenancy agreement. But damp is a repair and safety issue, and if woodlice are a symptom of it, report the damp.

Citizens Advice, which covers England, says your landlord will probably be responsible if the tenancy agreement says so, if the problem stems from a repair they have not made, or if it makes your home unsafe. They are usually only responsible once they know. So tell them now, in writing, with dated photos and your notes of when and where you saw the woodlice. Separately, the Homes (Fitness for Human Habitation) Act 2018 requires homes in England to be fit to live in, and the GOV.UK tenant guide lists damp and mould among the hazards. It does not cover licences to occupy, such as many lodgers. It sets out the steps, from a written report and reasonable time for repair to a county court claim.

Awaab's Law applies to social housing. GOV.UK guidance says council and housing association landlords must investigate a significant damp or mould hazard within 10 working days, send a written summary within 3 working days of finishing, and make the home safe within 5 working days of finishing. Further work must start or be planned within 5 working days, and begin within 12 weeks at most. Emergency hazards must be investigated and made safe within 24 hours. If the landlord does not comply, use its complaints process, then go to the Housing Ombudsman. The guidance does not mention woodlice, so report the damp as the hazard and mention the woodlice as a sign.

Private tenants do not have those deadlines yet. The Renters' Rights Act 2025 gives the power to extend Awaab's Law, but the government's consultation runs until 18 December 2026, and regulations are still needed. Today private landlords must act within a reasonable time. Your council can inspect, often through environmental health, at no cost to you, and it must act on the most serious category 1 hazards. That consultation also says councils can now penalise landlords up to £7,000 for failing to address them. The GOV.UK guide adds that council enforcement can help protect you from retaliatory eviction.

GOV.UK also calls it totally unreasonable to blame damp and mould on lifestyle choices, and says that the root causes are building defects, poor ventilation, inadequate heating and poor energy efficiency. So if you are told only to open a window, keep your records and ask what has been done about the cause.

Landlords should see a tenant's report of woodlice as a free early warning. Clearing an air brick costs nothing, and a blocked one under a timber floor can end in a repair bill. Keep the repair records, and our Ilford pest control page covers the local points for landlords. If you are moving out, the end of tenancy cleaning checklist helps with the rest.

We would rather tell you when not to book. If you have found the leak, cleared the air brick or moved the pots, and numbers are dropping, you are finished. A few woodlice in winter do not need a visit, and no treatment can stop new ones walking in from the garden.

A visit is worth the money in a few cases. If live woodlice keep turning up after you have done the checks, a second pair of eyes on the routes and the outside walls can save you weeks of guessing. If you are not sure what the creature is, an identification can settle whether you need treatment at all, which matters if it turns out to be a pest with a real cost. If you are a landlord, or you are buying a property, a written record of what was seen and where can be useful. And if there is a true large-scale problem, such as a commercial basement or a damp void that cannot be fixed, targeted control can make sense alongside the building work.

Be wary of anyone who wants to spray before they have looked for moisture, sells a long contract for woodlice, or says that they are dangerous. They are not. If you have mixed signs, such as droppings or gnaw marks as well as woodlice, an inspection becomes better value. Our guides to mouse droppings and rat droppings can help you tell what you are looking at. See also how we compare prices across pests before you book anything.

Start with a message, because it may save you a visit. Tell us the rooms, the time of year and what you have checked, and send a photo beside a ruler if you can. If it looks like a simple seal-and-sweep job, we will say so. Our pest inspection has a starting rate of £60 and covers signs and entry routes. The final price depends on property size, the areas to inspect and access to voids or outside spaces, and it is confirmed in writing before booking. Any follow-on work is discussed before it is booked.

Woodlice control is priced for each property, as it depends on how far the activity has spread, the rooms affected, the likely entry points, and the ventilation and moisture work needed alongside it. We will not quote a fixed figure until we know those. Where sealing is the answer, our price list shows entry-point mesh proofing at £45 to £85, and a follow-up proofing and sealing package at £60, confirmed in writing for your property. You get a safety report, and if the job needs a plumber, a builder or your landlord first, we will tell you.

If more than one visit is agreed, our packages by property size come with written guarantees of 1 month on two visits and 3 months on three visits, plus follow-up and proofing advice. Most woodlice cases should never need one. If the creature turns out to be something else, the prices change, and the table below shows the common ones.

Council help is limited. Clackmannanshire Council does not treat woodlice and points people to private firms. Redbridge Council's pest control page, for our home borough, does not list woodlice among the pests it treats or those it refuses, so ask before you rely on it. We are based on Clements Road in Ilford and cover London, with public liability insurance. Our phone lines are open Monday to Saturday, 8am to 8pm. You can contact us with a photo at any time, and our prices page has the full list.