Identification of the presence and impact of Japanese knotweed on development sites

Abstract

Japanese knotweed is an alien species, which is spreading rapidly through the UK. Its root growth can penetrate many building materials, causing damage to infrastructure and buildings. This means that its discovery heralds potential property damage, increased costs and project delays. Its spread across property boundaries is actionable under law of tort, and its control is difficult, expensive and closely controlled by statute. These control methods, plus some innovative ones, and their limitations are outlined, as is the legal framework which protects the environment from further spread of Japanese knotweed. These particularly affect transport of material containing Japanese knotweed and treatment with hazardous chemicals. The duty of a competent surveyor to discover knotweed during a building, site or similar survey is established, and the consequences of failure to do so outlined. The paper concludes by recommending the Japanese knotweed code of practice as the basis of any advice offered in respect of treating Japanese knotweed.