When a major construction project occurs, particularly on greenfield sites it can frequently disturb rats that may already be present in that location or who habitually move through existing watercourses in that area.
Building on brownfield sites can also present problems. Disturbing flagstones and the demolition of existing old buildings (which may already harbour rodents) can displace the rat and mouse populations. As the construction site becomes more established portable site accommodation like site offices, canteen, toilet blocks etc… will be deployed offering rodents ideal harbourages. Another issue on sites can be the opportunities packaging and stored materials offer rodents. Rats burrow and make their nests under shelter such as timber stacks, piles of rubbish and untended vegetation. The increase in construction workers and other tradesman on site bringing food with them and creating litter will make the area even more attractive to rats and mice.
The potential health hazards to site workers, such as Weil’s disease presented by an infestation of rats or mice are well known. However rodents can also cause a large amount of structural damage. Rats in particular can undermine the fabric of buildings and can damage drains and sewers by burrowing between joints in the surrounding earth and behind brick sewers. Rodents kept their incisors in check by constant gnawing. Pipework is sometimes gnawed which can cause flooding, and gnawing of electrical wiring can be a potential fire hazard.
Pest factors should really be considered as early as the design stage of a building. For example, placing fine mesh over air bricks to prevent rats and mice entering a building, and addressing the issue of voids where there will be a ducted heating system (a multi-occupancy development for example), as these areas can provide rats and mice with access to the entire structure, making subsequent control very difficult. Drains and sewers could be specified with hinged plates, not only to help combat potential flooding issues, but also to stop rats entering properties via this route.
Minimising the impact of rodents during construction requires the developers and site managers to recognise the key signs of pest activity. This can be an issue on building sites, so following the rule ‘prevention is always better than cure’ involving a professional pest controller at the earliest stages of building development means that the site can be carefully monitored whilst construction occurs. It also allows any pest issues to be addressed swiftly before they can become major concerns.