How likely are bed bugs to spread between flats?

If you’ve ever wondered how likely it is for bed bugs to spread between flats, there’s only one answer – very likely. A study published in September 2015 described in detail the experiments conducted in 6 apartments in 3 New Jersey housing buildings. The researchers used a mark-release-recapture method to track the movement and dispersal of bed bugs within the buildings, which led to some disturbing findings.

First, the experiments have proven that bed bugs can easily spread between neighbouring flats even without a human carrier, and second, that these pests migrate even to vacant units and survive for months without a blood meal. The experiment also showed various ways bed bugs spread in blocks of flats.

Today, we are going to share with you what increases the risk of a bed bug infestation spreading through the building and how to prevent it.

People can unknowingly carry bed bugs from one place to another on clothes, furniture, bags, and other personal belongings. But friendly visits between neighbours are not the only way bed bugs travel between flats. Communal areas like lifts, hallways, and utility rooms in older properties, or gyms in modern high-rise buildings, play a significant role in the spread of bed bugs through personal belongings. However, these pests are tiny and get through the smallest openings with ease, allowing them to move between flats even without human involvement. Here are a few of the pathways they use to spread through a building:

• Cracks and gaps in the walls – The partition voids in old Victorian and Edwardian properties converted into residential buildings with flats provide bed bugs with an excellent pathway to neighbouring units. Even the tiniest cracks in the wall or the spaces behind skirting boards allow the tiny bed bugs to pass through.
• Electrical installations – all the cable voids in the buildings, the spaces around electrical boxes, even behind light switches and outlets, provide bed bugs with convenient pathways between flats.
• Plumbing installations – although bed bugs actively avoid wet surfaces, when there are severe infestations or a large population in an empty unit, these pests may use utility voids, pipe chases, pipe shafts, and boxes to search for a new host.
• Air ducts – bed bugs are excellent climbers, so they can travel even through high-placed voids like extractor fans or air bricks.
• Gaps under doors – Bed bugs can and do travel between units by slipping under the entrance doors and through hallways.

As you can see, bed bugs can enter any flat through various places. However, there are a few things that dramatically increase the risk of spreading:

Adjacent Walls, Floors, and Ceilings

Bed bugs are more likely to disperse to adjacent units than to a random flat of the building. During an infestation, all neighbouring flats, as well as those above and below, should be closely monitored. Our experience shows that bed bugs can cross between terraced and semi-detached houses, too. Bed bugs can spread to any adjacent space, not just in residential properties but also in commercial buildings.

Severe Infestations

The spread of bed bugs between flats depends on the severity of the original infestation. With light infestations, the risk of pest dispersal in the building is relatively low, but with moderate and severe infestations, dispersal becomes increasingly likely. When most people hear about a home with a large, untreated infestation, they often imagine it occurred due to a lack of hygiene or carelessness. However, as we explained in our previous post, “Can I Get Bed Bugs From My Neighbours?“, this isn’t necessarily the case. The truth is, quite a large percentage of people don’t react to bed bug bites – no itchiness, swelling, or any other visible symptom. The lack of bites and discomfort often allows the population to grow unnoticed for quite a long time before other signs of the infestation become obvious, and people react.

Infestations in Empty Units

When residents of an infested unit suddenly move out of their flat, bed bugs don’t just die. They are very resilient and can survive for months between bloodmeals, waiting patiently for the next occupant. The lack of food doesn’t stop the bed bug life cycle – they continue mating, although it can lower the amount of eggs they lay. However, some of the surviving pests find a simpler solution to this problem – moving in next door.

Disrupting Bed Bugs’ Habits

Anything that disrupts household routine can push bed bugs into neighbouring units. Moving furniture can make them feel exposed and unsafe, leading them to search for another hiding spot, which is not necessarily in the same flat. If you suddenly start sleeping in another room, or if your new job requires regular business trips out of town, some pests in the unit may move into adjacent areas and flats.

Incomplete Treatment

Treating a bed bug infestation in a flat or a terraced house requires a different approach than treating a detached house. You have to put in extra effort to ensure the entire population is eradicated successfully, rather than being dispersed between units. Here are a few examples of incomplete treatment that can push bed bugs to scatter through a building:

Inefficient Pest Control Measures

The worst spreads, however, often come from DIY treatment attempts. Often, when people try to get rid of bed bugs on their own, they focus solely on pesticides, completely ignoring non-chemical methods like steaming, hoovering, heat treatments, or physical control measures like encasing their mattresses. Bed bugs are resistant to most over-the-counter sprays, and most insecticides kill them only on contact. Also, store-bought products can’t kill the eggs, even if you manage to find all of them. The lack of an Integrated Pest Management approach pushes bed bugs out of the flat, spreading the infestation through the building.

Falling to Monitor Adjacent Units

When treating an infestation in a flat, it is crucial to examine all adjacent areas for signs of bed bugs. As these pests travel through the tiniest cracks, all neighbouring units, including the empty ones, need to be observed post-treatment to ensure they are not migrating there.

Ignoring Possible Hidden Harborages

Reliable pest control companies always check for bed bug hiding spots not only inside the flat they are called to treat, but also in the surrounding areas. Skirting boards and cracks in hallways often become escape routes for bed bugs scattering from a treated flat.

Poor Preparation Before Treatment

Decluttering and thorough hoovering of all infested areas allows pesticides to reach the smallest cracks and crevices that harbour bed bugs and kill them. However, when there is a bed bug problem, thorough cleaning should not be limited to the affected flat; it should also cover the surrounding hallways and stairwells. Any stored items left in these areas can serve as temporary hiding spots for bed bugs, allowing them to move unnoticed between flats.

Nobody’s immune to unknowingly bringing bed bugs into their home, so there’s no need to feel shame or point fingers. However, if there are bed bugs even in just one flat, the main goal is to treat the infestation as soon as possible to prevent the pests’ dispersal. Here’s what to do:

• Call pest control professionals – we cannot stress this enough – call an exterminator as soon as you notice any signs of bed bug infestation, even if they seem insignificant – a suspicious bite, a single unidentified crawler near your bed. Even if it turns out that your suspicions were groundless, it is better to be safe than sorry. A few randomly introduced bed bugs can turn into a severe infestation in just 2 months.
• Notify the estate management – fighting a bed bug infestation in a block of flats is a shared effort. You don’t need to go knocking on doors from door to door, informing your neighbours; this is your building manager’s job. All you need to do is inform them as soon as the infestation is confirmed.
• Prepare the flat for treatment – experienced exterminators usually provide a list of instructions on how to prepare the flat for treatment. It usually includes tasks like decluttering, thorough hoovering, and washing clothes and bedding at high temperatures. Follow all the instructions to the letter to ensure efficient treatment. And whatever you do, never move any personal belongings or furniture to another area or the hallway, even for a while. If you have to discard any item, put it directly in the bins outside; you might unknowingly help spread bed bugs between flats.

What to Do If You Are Renting

A bed bug infestation, even in a single flat, is a problem that shouldn’t be taken lightly. Here’s what to do to prevent bed bugs from spreading in the building if you rent or lend a rental property.

If you are a Tenant

Although the flat you are renting isn’t your property, it is your responsibility to act fast, so you need to:

• Inspect the place for signs of bed bugs. Look for dark spots on mattresses and bedding, live bed bugs, shed skins, or an unusual musty smell.
• Take pictures of any visible signs you can find and send them to your landlord.
• Report the issue to the building manager, so they can take the necessary actions.
• Prepare your flat for treatment. Declutter the area and remove as many items from furniture and floors as possible to ensure the exterminators can easily access all areas.

If you are a landlord

It is in your best interest to take all reports of bed bugs seriously to prevent widespread bed bug infestations in the building. As soon as a tenant reports an issue, arrange for a professional inspection. It is important to hire a reliable pest control company. Only experienced, certified exterminators can determine the full extent of the problem, implement an efficient treatment, and lay out Integrated Pest Management protocols to help prevent future infestations.

If you suspect bed bugs in your flat, don’t wait. We can help you tackle the problem quickly and discreetly. Visit our domestic bed bug services page to get a quote and arrange an inspection.