Japanese Knotweed – Court Rules That Owners Are Entitled To Damages Due To A Reduction In Property Value

The Court of Appeal has recently ruled that the reduction in the value of a property due to the encroachment of Japanese knotweed from neighbouring land was a recoverable loss for the property owner impacted.

Davies v Bridgend County Borough Council [2023] EWCA Civ 80

Case summary

The Claimant in this case (Mr Davies) purchased a property in 2004 which bordered land that was owned by Bridgend County Borough Council (the Defendant). Unbeknown to the Claimant, the property he brought was infested with Japanese knotweed which had spread from the Defendant’s land.

In 2012, the Royal Institution of Chartered Surveyors (RICS) released a report outlining the problems that Japanese knotweed could cause. However, despite this report, the Defendant didn’t take any action to treat and remove the knotweed until 2018.

The Claimant became aware of the presence of Japanese knotweed on his property in 2019. He then raised his concerns with the Defendant, which then led to Court proceedings being issued.

Damages amounting to £4,900 for the residual reduction in the value of the property after 2018 was sought by Mr Davies.

What is Japanese knotweed? How can it cause structural damage to a property?

Japanese knotweed is an invasive pernicious plant that was first introduced to the UK as an ornamental plant in the 19th century. The weed can severely damage and impact hard surfaces, including tarmac, brickwork, and concrete.

Japanese knotweed, which generally grows rapidly (up to 10cm per day) and spreads via its underground roots or rhizomes (which can go down as deep as three metres), and impact and damage a property’s structural integrity and substructures by affecting weak spots, such as cracks in masonry.

The impact of Japanese knotweed could potentially mean:

It is known to be very expensive to treat and remove the knotweed, and if the weed is not fully removed from its source, then it is likely that it will return.

Japanese knotweed case law – Network Rail v Williams

In 2018, in the landmark case of Network Rail v Williams, the Court of Appeal ruled that two property owners, whose homes had been affected by Japanese knotweed, should be entitled to damages due to the structural damage caused to their properties.

The owners of the properties, which were two adjoining bungalows in South Wales, sought compensation from Network Rail, which owned the land behind the bungalows.

The residents of Llwydarth Road, Maesteg, first complained to Network Rail about the Japanese knotweed back in 2013. However, it had been present on Network Rail’s land for at least 50 years.

Following various Court decisions, the owners of the two properties won their claim for compensation due to the damage caused by the Japanese knotweed. The diminution in value claim brought by the Claimants was ultimately dismissed by the Court of Appeal, due to it not being recognised as a head of loss in the tort of nuisance. However, compensation was awarded to the property owners for their loss of quiet enjoyment and amenity.

Davis v Bridgend County Borough Council – Court proceedings

Back to the case of Davis v Bridgend County Borough Council, in the first instance decision, it was ruled that the Defendant was in breach of its duty in nuisance between 2013 and 2018 and this was accepted by the Court. The question of significance was if this duty continued after 2018 after the Council had treated the Japanese knotweed on its land. This is what Mr Davis sought damages for.

This claim was dismissed at first instance with the District Judge relying on the Court of Appeal decision in Network Rail Infrastructure Ltd v Williams, due to the Court of Appeal deciding that it was wrong to find that the reduction in the value of a property directly because of Japanese knotweed was an actionable nuisance due to it being a purely economic loss – there wasn’t any physical damage or interference. The District Judge further stated that the objective of the tort of nuisance isn’t to protect the value of the property as a financial asset.

The case then proceeded to the Court of Appeal, which noted that in cases, such as this, where the aspects of nuisance are met, it doesn’t mean that a Claimant is unable to recover compensation due to a financial loss.

With regards to Network Rail v Williams, the Court of Appeal found that the Japanese knotweed found on Network Rail’s land, despite being near the boundary, caused a diminution in the market value of Mr Williams’ land but that diminution didn’t come about as a result of physical damage or interference, which meant that it didn’t amount to a nuisance. That said, the Court of Appeal did recognise that if the property value diminished due to interference with quiet enjoyment or amenity as a consequence of Japanese knotweed, damages including the reduction in the property value can be awarded to claimants.

Mr Davis was awarded £4,900 in damages.

Comment

This case highlights the importance of treating Japanese knotweed as soon as it is identified as the consequences of not treating it can be costly, specifically to property owners. The judgement, in this case, could also potentially lead to further claims where knotweed treatment began too late, e.g., it has already spread to neighbouring land.