Sheet metal contractors and journeymen must be licensed by the Department of Consumer Protection. 

"Sheet metal work” is the installation, erection, replacement, repairs, or alteration of ferrous or non-ferrous ductwork systems. Written complaints about sheetwork may be filed with the Department of Consumer Protection. 

Occupational & Professional Licensing Division
Department of Consumer Protection
450 Columbus Boulevard, Suite 901
Hartford, Connecticut  06103

Email: DCP.OccupationalProfessional@ct.gov