The Sponsor is absolutely required to have licensed and insured contractors and any sub-contractors must be licensed and insured. A sponsor just cannot do as he wishes he needs to abide by NYC housing codes. Email and Call the Housing department and provide the sponsor with a copy of the email. What action is the Board and the Management taking on this matter? Is the Sponsor the management company too? How many seats on the board does the Sponsor have? Where is the Board President and that is who should be objecting to this illegal work.