Loft condominium owners at 111 Hudson St. in Tribeca who discovered a $2.5 million structural defect after moving into the building cannot sue on securities law or fraud claims, but can go forward with a breach of contract cause of action, a Commercial Division judge ruled.

Justice Anil Singh, in a July 31 decision released Friday, said the offering plan under which the six condo units at 111 Hudson St. were marketed in 2008 constituted a contract between the sponsors who converted the building to a condo and the plaintiffs who purchased units.