By 1730, Brettingham is referred to as a surveyor, working on more important structures than cottages and agricultural buildings. In 1731, it is recorded that he was paid £112 (£ in ) for his work on Norwich Gaol.
By 1730, Brettingham's expertise as a surveyor became evident, with him undertaking more complex projects than ordinary homes and rural structures. A year later, records indicate that he received £112 (£ in ) for his contribution to the construction of Norwich Gaol.