Building the sea wall for the Charlottetown convention centre was problematic. (CBC)

The Charlottetown Area Development Corporation has filed a $5 million lawsuit against three firms involved in the building of a seawall for the waterfront convention centre.

The seawall collapsed twice during construction, unable to find firm footing on the soft, silty bottom of Charlottetown Harbour. CADC is suing Charlottetown engineering firm Harland Associates, Birt & MacKay Backhoe Services of Charlottetown, and J.D. Irving Limited.

The suit charges that the firms failed to build the seawall properly initially, and their attempts to fix it also proved unsuccessful. CADC says the problem was finally solved when it hired new engineers and construction crews to take over.

J.D. Irving and Birt and Mac Kay are already suing CADC for a total of $3.6 million for what they say is money owed.

The $5 million counter suit from CADC follows a forensic engineering study commissioned by the development corporation and completed this summer.

Construction on the convention centre is slated to be complete next July. Sources close to the project say the legal battles could go on for years.