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Pest control in offices

Pests in offices can present a serious health threat to people working there so it is vital to ensure that the office does not become a breeding ground.

Any potential points of access and sites for pests to make their homes need to be identified, monitored and protected to prevent a pest infestation in the office environment.

Rentokil has decades of experience in protecting offices from pests. Our integrated pest management approach incorporates both preventative and responsive strategies to provide the most efficient and consistent pest control using industry-leading technology.

Contact Rentokil for all your office pest control requirements

Impact of a pest infestation

A pest infestation can have a major impact on office management, including.

  • Repair costs
  • Damaged reputation
  • Business disruption
  • Complaints leading to rent reductions and compensation claims
  • Impact on staff morale
  • Rental contract termination
  • Revenue loss from unrented space

A study on the business impact of pests commissioned by Rentokil Initial of 1000 non-food businesses across five countries (including offices) found that staff morale was the most commonly cited impact on business costs following an infestation.

Almost half of businesses reported that it took more than two weeks for the disruptive period to be over and 15% of businesses said they suffered a drop in revenue and reputational damage. Increased maintenance and repair costs and damage to goods was also a common impact of an infestation.

Top pests found in offices

Rodents, a wide variety of insects and birds can exploit many opportunities to find shelter, food and water in office buildings. Each pest has unique characteristics that allow it to exploit weak points in buildings, but which also give away its presence when infesting a building. These are described below for the most common pests:

  • Rats and mice
  • Flies
  • Cockroaches
  • Ants
  • Bed bugs
  • Fleas
  • Birds
  • Stored product insects

Rats and mice

Mice and rats are the most common pests found in offices. Their inquisitiveness and agility enable them to exploit many types of weakness in in buildings to find a way in. They can climb rough vertical surfaces and walk along thin cables, wires, pipes and branches of trees and bushes growing close to buildings. They can squeeze through tiny gaps or gnaw around them to make a bigger hole to gain access to a building — in wood, plastic or soft masonry.

There are multiple hazards from rodents including:

  • Contamination along their trails and anywhere they visit with urine, droppings, and filth picked up from the environment
  • Contamination of food and surfaces with pathogens causing a number of serious diseases, including salmonellosis, leptospirosis, toxoplasmosis, Lyme disease, rat-bite fever
  • Damage to buildings and fixtures, especially to wiring and electrical equipment. Brown rats can also cause extensive damage to sewer systems by burrowing
  • Damage to food, containers, packaging
  • Rodents carry parasites, including ticks, fleas, lice and mites that can infest buildings and are also vectors for many diseases

Signs of rodents

Rats and mice provide a range of clues that indicate their presence:

  • Smudge marks along runs caused by their oily fur: such as along walls, pipes and cables, around holes
  • Droppings: rat droppings are 10-20mm and mice droppings 1-2 mm, the size of rice grains
  • Sightings of live or dead animals
  • Holes in the ground next to buildings. Brown rats dig burrows in the ground for shelter, food storage and nesting
  • Noises: squeaks, gnawing sounds or scurrying sounds in ceiling and floor spaces or other hidden spaces such as partition walls
  • Gnaw marks on wiring, food, packaging, around holes
  • Shredded materials such as cardboard boxes, paper, roof insulation, which rodents use to line their nests
  • Smell: rats and mice urinate frequently as they move around and this creates an ammonia smell
  • Nests: in hidden spaces such as roof areas, attics, suspended ceilings, cable ways under floors
  • Rodent runs on floors can be picked up with UV light that highlights urine stains that they deposit as they move and their footprints can be highlighted by laying down powder


A number of fly species can become pests around offices. They are attracted by food smells from kitchens, stored food and waste food, whether in garbage bins inside or outside the building. Flies can also be a pest if there are businesses nearby that provide breeding grounds, such as poultry and pig farms or food businesses with garbage containers that are not managed properly.

A fly problem is easily identified by an unusually large number of adult flies seen in and around an office. The most common fly pests in offices are:

  • House flies: house flies and other filth flies can carry a wide range of disease-causing microorganisms such as Salmonella, E. coli, Camplyobacter. They feed on any food material, including rotting meat, fruit and vegetables and faecal matter, picking up pathogens and carrying them to food and surfaces in office kitchens and desks where food is stored and eaten.
  • Fruit flies: they are attracted by sweet, especially fermenting, liquids in fruit, vegetables and drinks. They only require small quantities to feed on and breed in. They can be found around:
    • garbage containers with rotting food — inside or outside offices
    • over-ripe fruit, and some vegetables
    • old drink bottles or other containers with sugary liquids
    • in spills of sugary liquids that are not cleaned up, especially in cracks in wet floors
    • drains with food waste
  • Drain flies: these breed in biofilms that can build up in drains or other places in and around buildings that collect moist organic matter. They are regarded as harmless but can be a nuisance in large numbers
  • Sciarid flies (fungus gnats): Sciarid flies can become a nuisance if there are plants in an office. Their larvae feed on the root hairs of young plants and the adults on algae and decaying plant matter. An infestation is encouraged by over watering plants, giving them suitable conditions for breeding. The adults are around 5mm long with long antennae and will fly around people sat at desks, but they do not bite.
Discover how Rentokil is leading the way in fly control


Cockroaches are attracted by food, moisture, suitable temperature and harbourage. They are more of a problem in warmer countries, but can be a particular problem in buildings because of their ability to hide in small, difficult-to-reach places.

Cockroaches feed on decaying matter, mould, faecal matter and can carry a large number of diseases and parasites into the office environment and contaminate food, surfaces, cupboards, and packaging. They can eat any type of food and even cardboard, but only need small residues or spills of food or liquid to survive on.

Cockroaches are generally nocturnal so are unlikely to be seen during office hours unless disturbed. They can shelter in cracks and crevices in walls and floors, around pipes and wiring, inside equipment and machinery and hidden spaces that provide the right temperature and humidity. They can also inhabit drains and sewers and access buildings through the pipework.

Signs of cockroaches are:

  • Droppings and bodily secretions stain surfaces and leave a foul odour around infested areas, in food and packaging
  • Egg cases
  • Shed skins
  • Live or dead insects

These may be in hidden areas under, behind or inside cupboards and desks or other office furniture, or even items such as toasters that accumulate food debris inside.


Ants can easily get into a building through any small gap in doors, windows, air vents, etc to forage for food and the odd one is unlikely to be a problem. However, if they are near where food is stored you don’t want it to escalate into an infestation. Signs of an infestation are:

  • Large numbers of ants in a kitchen or food storage area
  • Ant trails leading to areas with food. These will lead to a nest in the opposite direction, usually outside
  • Ant nests next to the building or in the structure. Some ant species such as the invasive pharaoh ant are so small (1-2mm) that they can make a nest in any tiny space and can access food through the tiniest gaps in containers, cracks in walls, gaps round windows and doors, air vents, etc. They can also eat their way into packaging and make their nest inside it

Bed bugs

Bed bugs can be brought into any building where there are large numbers of people visiting, including employees, visitors, contractors. They can also be carried into a building in furniture or other items such as electrical equipment.

Once inside a building, bed bugs will find shelter in small hidden places, especially in furniture where they are most likely to encounter a human for a blood meal. They are most likely to be found in storage areas, offices or lounges with upholstered furniture, or areas where people may rest. They are mainly nocturnal feeders but will feed at any time if hungry.

The signs of bed bugs are:

  • Small dark spots on furnishings, caused by bed bug faeces
  • Unpleasant sweet musty odour
  • Shed whole skins of different sizes from different larval stages found in clusters along furniture seams
  • Bed bug eggs in cracks and crevices of furniture or fittings such as skirting boards
  • Live insects
  • Insect bites


Fleas are brought into a building by people, pets and pests. There are several types, which are specific to their favoured animal: cat, dog, bird, human and rat fleas. Each type of flea prefers its normal host but will attempt to bite other animals, including humans before dropping off.

The main signs of a flea infestation are:

  • People reporting bites, especially near the ankles
  • Live insects
  • Flea droppings, which look like ground black pepper in carpets and on seating
  • Flea eggs in carpets and on seating. They are about 0.5 mm long, oval and white, which makes them difficult to see


Birds can become pests on the roofs and ledges of office buildings and also roof spaces where there is access from outside, such as through vents or broken tiles. The main bird pests are pigeons, seagulls and sparrows. The problems caused by birds include:

  • Bird droppings deface and corrode buildings, paved areas and vehicles
  • Bird droppings carry numerous diseases and parasites such as Salmonella, E. coli, bird flu
  • Parasites carried by birds include mites, fleas, ticks and beetles that infest their nesting and roosting sites and can move into buildings when their hosts have moved away
  • Bird nesting materials can block roof drains and guttering causing flooding into the building
  • Physical damage such as lifting roof tiles
  • Gulls can attack people in the breeding season

Stored product insects

Stored product insects (SPIs) can become a pest where dried foods are stored for long periods, including: cereal products, nuts, dried fruit, powdered milk, tea, preserved meats. In an office this could be in the canteen, staff kitchen facilities or in desks where people store their snacks.

SPIs cover a wide range of pests, including beetles, weevils, moths (larvae) and mites. They are more likely to infest products in packaging that has been opened, but some can chew their way through packaging made of paper, cardboard, plastic and foil.

Signs of stored product insects include:

  • Live or dead insects, larvae or pupae in food and packaging
  • Holes in packaging
  • Larvae, pupae or silken webbing in the area where food is stored, such as on shelves, window sills, cracks and crevices
  • Damage to stored products, such as holes in nuts or grain

Office pest control measures

The main strategy is to prevent a pest infestation in offices by denying pests access into the building and any food, water and shelter.

Rentokil can advise customers how to protect offices against pests and comply with specific legislation. We can offer state-of-the-art pest control solutions and world class services to deal with pest infestations and prevent them recurring.

These are some of the steps that businesses can take to prevent pest infestations in offices:

  • Clean kitchen areas frequently and clean up spills and leftover food around the office
  • Remove food waste from the building frequently
  • Clean throughout the offices regularly
  • Store garbage outside in pest proof containers, dispose of regularly and keep the area clean and free of debris
  • Train cleaning and maintenance staff to identify the signs of pests and potential entry points
  • Maintain the office building to prevent holes and gaps appearing in the structure that could be exploited by pests, including around door and window frames, pipes, cables and air vents, potential pest harbourage places are eliminated
  • Keep doors shut when not in use
  • Identify any leaks in kitchens and washrooms and repair them as soon as possible
  • Periodical quality assure the cleaning regimes for your office premises, including kitchens, washrooms, store cupboards, floors, carpets, curtains, etc
  • Check office plants for pest insects periodically to stop them from spreading throughout the office
  • Implement a clear desk policy to deny small pests food and shelter
  • Encourage colleagues to report any pest sightings and advise them not to try and handle the situation themselves for their own and others’ health and safety
  • Issue regular communications (eg emails, notices, posters) to all colleagues about keeping the spaces they use clean and the procedure to report any pest sightings or other incidents that could pose as health risks
Contact Rentokil for comprehensive industry-leading pest control

Proper use of pesticides

Staff in offices should not apply pesticides themselves because of the risk of ineffective and inappropriate use. This can result in contamination with poisonous chemicals due to drip, drain, fog, splash or spray on food, materials and equipment.

Contacting a pest control professional is the most appropriate course of action in an office environment. Rentokil technicians are highly trained and will ensure that if it is necessary to use pesticides, the most suitable pesticides are used, they will be applied only where necessary and in an approved way that prevents hazards to employees, other persons and the environment.

Office fumigation

When an entire commercial building is affected by a pest infestation and alternative pest eradication measures are not sufficient, a fumigation treatment may be required.

Depending on its construction, the building may be covered in a tent or all entry and exit points are sealed to contain the fumigation gases.

The fumigation gas is introduced for the required time, so that it penetrates all parts of the building that the pest has infested. The gas is then ventilated from the tent to enable the building to be reoccupied.

The severe pest infestations that may require fumigation treatments include:

Contact Rentokil to find out more about office fumigation



UK pest control: 0808 168 9678
US pest control: (855) 234-5148