In August 2011 the Court of Appeal decided the case of Hirose Electrical UK Limited v Peak Ingredients Limited  EWCA Civ 987, and considered whether disrepair to a party wall could constitute a nuisance.
Units 20 and 22 on the Crownhill Industrial Estate, Milton Keynes, were occupied by Peak Ingredients and Hirose Electrical respectively. They were separated by a party wall constructed in breeze block. That party wall was described as “porous”; in short, there were insufficiently sealed gaps in the wall.
Hirose moved into Unit 22 in 1993. They manufactured parts for mobile phones. Unit 22 was split into light manufacturing and office uses. Peak moved into Unit 20 in February 2002. They manufactured food additives and coatings.
From the beginning of Peak’s occupation of Unit 20 Hirose’s employees made “frequent and vehement” complaints about the smell emanating from Unit 20. It was described as “spicy, peppery, or like curry or garlic”. The employees’ complaints included breathing difficulties by asthmatics, sinus problems and severe headaches, feelings of sickness and nausea, and dry throats. There were occasions when members of Hirose’s staff felt so nauseous they were sent home.
In October 2007 Hirose decided that could no longer abide the smells from Unit 20; they would have move. It vacated Unit 22 on 16 May 2008, and issued proceedings against Peak on 27 March 2009. They alleged that Peak had committed the tort of private nuisance. Hirose sought recover financial losses it alleged it suffered as the result of the nuisance, including the costs of moving premises.
The High Court
The High Court dismissed Hirose’s claim. Following Southwark v. Mills  1 AC 1, the ordinary, normal and reasonable use of premises by its occupier was not in itself a nuisance. There had to be more; an activity that took their behaviour outside the normal and reasonable use. On the facts of this case Peak’s use was within the ordinary, normal and reasonable use of a unit in a light industrial estate.
The Court of appeal
Hirose appealed the Court of Appeal. One of Hirose’ four ground of appeal was that the judge had failed to consider whether, having regard to the porous nature of the party wall, Peak’s activities could be reasonably or conveniently done within Unit 20 at all.
The Court of Appeal dismissed the appeal on other grounds, but did consider and reject this argument. Although the porous nature of the party wall was relevant to the penetration of the smell into Unit 20 and as a subject of remedial work, no blame on that point could be allocated to the parties or to the landlord. In short, the want of repair to the party wall would not transform Peak’s reasonable use into an unreasonable use.
This appears at odds with the decisions in cases such as Bradburn v Lindsay  2 All ER 408 and Brace v South East Regional Housing Association Ltd (1984) 270 Estates Gazette 1286, in which it was held that disrepair to a party wall could give rise to a claim for damages in nuisance.
It should be noted that the cases of Bradburn and Brace do not appear have been brought to the attention of the Court of Appeal in this case. Had the Court been aware of these earlier authorities the Court’s decision might have been different.
However, assuming that the Court’s decision would have been the same, these apparently conflicting decisions may be resolved by looking to the effect of the disrepair. In both Bradburn and Brace the effect of the disrepair was a withdrawal of support in breach of the easement of support under s. 38(1) of the Law of Property Act 1925.
It therefore seems that a defendant must be in breach of a positive obligation to repair the wall, such as that imposed by the easement of support, before they can be liable in nuisance for the effect of the disrepair. This would be consistent with the Court’s reasoning in Hirose, as the Court specifically noted that Peak was under no obligation to repair the wall.
The Court also noted (and not for the first time) that the costs of the litigation, which had not achieved anything, far exceeded the cost of a constructive solution by insulating the party wall against the smells.
In conclusion, it seems that disrepair to a party wall will only give rise to liability in nuisance if the disrepair is in breach of a positive obligation to repair, for example in a repairing covenant in a lease, or the easement of support.