A flaw in the design of a building is sometimes discovered by the owner who procured the project in the first place. More often, however, it is the ultimate occupier, who has no contract with the design team, who discovers their building is dodgy only after they have been in it for a while.
The landmark decision in Murphy v Brentwood (1991) held, and I paraphrase here, 'no contract - no claim'. In its wake, claims against design professionals by ultimate occupiers in respect of latent defects became rare.
But to every legal rule there is an exception, and not even the seven Law Lords who decided the Murphy case sought to let the designers off the hook if the defect in their design was likely to injure someone or damage property other than the building itself.
The point was illustrated admirably in the case of Morse v Barratt (Leeds) Ltd (1992) in which residents of a new housing estate complained that by increasing the level of fill behind a retaining wall at the rear of the development, Barratt had made the wall liable to collapse.
When the residents were served with a local authority dangerous structures notice, they were obliged to rebuild the wall. The court had no difficulty, however, in holding Barratt liable for the costs incurred.
In Blaxall Securities Ltd v Sheard Walshaw Partnership (judgment 22.1.02) the defendant architect Sheard Walshaw Partnership (SWP) admitted that its design of the roof of the claimants' industrial unit was defective and the gutter was unable to cope with heavy rainfall.
The Court of Appeal has recently exonerated SWP from any liability for subsequent flood damage.How so?
The building, described as a large shed, had twin-pitched roofs running lengthwise, separated by a valley gutter with a flat base and vertical sides. In the base of the gutter were outlets leading to drain pipes.
There was, however, no seal between the lip of the gutter and the underside of the metal roof. If the gutter overfilled, water would pour into the building. And this is precisely what happened on two occasions in 1995, damaging the contents of the building.
The experts agreed that some sort of overflow was needed to ensure that if, for whatever reason, the gutter overfilled, the overflows would take the excess water away.
It was accepted that SWP was at fault but it argued that when the claimant bought the building it had an opportunity to inspect it and that its own surveyor ought to have spotted the problem with the roof.
SWP went further and pointed out there had been signs of flood damage from the outset, which was wrongly attributed to blocked outlets and debris in the gutter.
In short, it said that the roof may have been faulty, but it was obviously so. The defects were not latent, but patent - and you can have no claim in tort for patent defects.
Unattractive though such an argument may sound at first, the Court of Appeal agreed with it. It said that the concept of a latent defect is not a difficult one. It simply means a concealed flaw that would not be discovered during the sort of inspection one might expect the object to be subjected to.
Harking back to the days of Donoghue v Stevenson (1932), and the decomposing snail in the bottle of ginger beer, the court recognised that the consumer of a fizzy drink will not, in the ordinary course of things, bring in an expert to inspect the goods they purchased. In contrast, however, the buyer of a building almost invariably would.
The court found that the first flood was caused by a combination of blockages and absence of overflows, which the claimant's surveyor ought to have detected.
The cause of the second flood was a combination of the patent defects and a shortfall in the design capacity of the roof for the rainfall to be expected in the area, which was a latent defect.
Ultimately, however, the effective cause of both floods was the absence of overflows, a patent defect which ought to have been identified and remedied by the claimants.