The conservatory of Carrow House, once the home of the Colman family has also been given listed status.
A number of sites in Britain linked to the history of Colman's mustard are being given protection.
The Norwich factory where the condiment was made for more than 160 years is among them after it closed in 2020.
The conservatory of Carrow House - once the home of the Colman family - has also been given listed status.