Why London buildings suit cockroaches
Cockroaches want warmth, moisture and tight crevices, and a great deal of London supplies all three all year. Estates and older blocks carry hot water and heating pipes through shared ducts from floor to floor. Victorian basements sit close to damp drains. Shops, takeaways and restaurants with flats above share walls, pipework and bin areas with the homes over them, and commercial kitchens stay warm through the night. Cockroaches in any of these can travel well beyond the spot where they were first noticed.
Identify the species first
The German cockroach is small and light brown, with two dark stripes just behind the head. It stays close to heat and food, around fridges, cookers and dishwashers, and breeds quickly. The Oriental cockroach is bigger, dark brown to nearly black and glossy, prefers cooler damp places such as basements, drains and under floors, and struggles to climb smooth surfaces. German and Oriental cockroaches compares them properly. A clear photo, or one insect in a sealed jar, is useful when you book.
Signs and a night-time check
Because cockroaches hide by day, the evidence normally turns up first: tiny dark droppings, smear marks along edges, egg cases, shed skins and a stale, musty smell. The most telling check is to walk into the kitchen quietly an hour or two after the lights go out, switch on a torch, and look under the sink and behind the appliances. The signs of a cockroach infestation and why cockroaches appear at night explain what you are seeing.
Why sprays can scatter them
Reaching for a can of insect spray is a natural reaction. The difficulty is that many household sprays repel cockroaches as well as killing the ones they hit. The survivors retreat deeper into wall voids, electrical fittings and the flat next door, and the egg cases, which a spray does not reach, hatch regardless. In a block, that can turn one kitchen's problem into several. Spraying can also blur the picture of where activity is concentrated, which matters when the property is treated. If you have already sprayed, stop, and mention it when you book.
What you can safely do in the meantime
- Fix dripping taps and small leaks, and dry the sink and draining board last thing at night
- Keep food in sealed containers and clean grease and crumbs from behind the cooker and toaster
- Empty the kitchen bin every evening and keep the lid shut
- Put pet food away overnight
- Get cardboard boxes and paper bags out of the kitchen, since cockroaches shelter and lay eggs in them
- Note where and when you see them so a pattern emerges
Sticky insect monitors from a hardware shop are a safe way to see how many cockroaches there are and where they travel. Lay them flat against the wall under the sink, behind the fridge and beside the cooker, check them every few days, and keep them to show whoever comes to treat the property.
Kitchens: where they gather
A kitchen infestation usually centres on a handful of places: the warm motor area behind the fridge, the space beneath the oven, the back of the dishwasher and washing machine, the pipes under the sink and the hollow plinth below the units. Checking these with a torch shows how far the problem has spread. Where cockroaches hide in kitchens takes you through them one at a time.
Flats and estates
In a block, cockroaches follow risers, ducts and pipe runs between homes, so one flat dealt with in isolation may be reinfested from next door. Report it to your landlord, housing officer or managing agent, and ask neighbours whether they have seen any. Where several homes are affected, treating them together gives the best chance of a lasting result. Cockroaches spreading between flats covers the routes and who to tell. Finding them is no judgement on your housekeeping; see do cockroaches mean a property is dirty.
Restaurants, shops and other businesses
Food businesses have a legal duty to keep pests out of areas where food is prepared, stored or sold, and an infestation can lead to enforcement by environmental health officers. Act at the first sighting, keep a written record of what you find and what you do about it, and check deliveries and cardboard before they come inside. How cockroaches get into properties covers deliveries and second-hand equipment. Commercial premises are quoted per site, because every kitchen and building is different.
After treatment
Some sightings for a while after a visit are common, particularly as eggs hatch and disturbed cockroaches come into the open. What matters is that the numbers fall over time. Seeing cockroaches after treatment explains what is normal, and preventing cockroaches returning sets out the habits that stop the next ones settling in.
Booking
Cockroach control in London is £190 for a flat and £240 for a house; business premises are quoted per site. When you book, tell us the size and colour of the cockroaches, where you have seen them, whether anything has been sprayed and whether neighbours are affected. If what you have is a line of tiny insects rather than cockroaches, read getting rid of ants.
