Two supermarket chains are suing major contractors over alleged defects at superstores.

Waitrose is seeking more than £500,000 from Wates after part of the roof fell in two years ago at a store in Salisbury, Wiltshire.

Fellow retailer Safeway Stores is suing Interserve Project Services over a car park at an outlet in Oxted, Surrey.

According to its High Court writ, Waitrose is suing for damages over a design-and-build contract in 1997, and is seeking an indemnity for any claims made against it and any diminution in the value of its property.

Wates is alleged to have failed to provide sufficient systems to cope with rainwater and to have failed to comply with British Standards.

Waitrose estimates that repair works to the damaged roof will cost £550,000, but it is also seeking damages for lost profit.

Safeway alleges that Interserve failed to prepare its car park’s surface as specified and failed to repair cracks in the concrete.

Interserve finished work in November 1996; the deck membrane failed shortly afterwards.

Safeway blames the problems on breaches of warranty and claims that Interserve failed to comply with the contract.

Wates and Interserve said they were hoping to settle out of court.

Waitrose and Safeway were unable to comment.