A firm is being sued by the Government over substandard piling at five construction sites. The company, B+B Construction, has been linked to several such scandals and was recently removed from the Housing Authority's list of approved contractors. The Buildings Department said yesterday it had filed a writ against the company following a 15-month investigation into 15 sites. The investigation, which ended in September, discovered five of the sites had substandard foundations, it said. They were at Siu Lam, Tuen Mun; Blue Pool Road, Happy Valley; the Airport Railway Hong Kong Station; Airport Railway Kowloon Station and Airport Railway Olympic Station. Remedial work has been carried out. Director of Buildings Leung Chin-man said the contractor was being sued for contravening the Buildings Ordinance. Earlier this year, several people, including one employed by B+B Construction, were found guilty of laying faulty foundations on Airport Railway projects. The Housing Department and Buildings Department have said they will take measures to prevent such scandals. These include stepping up the departments' monitoring procedures and changing the subcontracting system and the lowest-bid arrangement. Housing Authority chairwoman Rosanna Wong Yick-ming has met professionals' representatives, including architects, engineers and surveyors to discuss the issue.