Sidnick is expected to join the NHBC next month in the new role of public and external affairs manager. He will report to the organisation's top PRO, media and comms manager Sarah Hamilton.
Sidnick said his role would be to work with policy makers to ensure that new housing conformed to environmental standards and was located in areas with good transport links.
Sidnick joined the BCC in 2003. Prior to that he worked for Conservative MEP Charles Tannock in the European Parliament.
A BCC spokesman said the group had yet to decide if it would replace Sidnick. It is meanwhile seeking a replacement for head of economic and corporate affairs Emmeline Owens, who left for HBOS (PRWeek, 16 June).