Work will also involve construction of a £9.25m library and archive as part of the major renovation job.
Piece Hall is an important part of Halifax’s history and was built to house prosperous cloth traders some 230 years ago. It has been called one of the 40 greatest public squares in the world.
The Georgian building is one of only two surviving cloth halls in the whole of Europe and has had a variety of uses over 230 years.
Work started today on the Piece Hall project, which is due to open in spring 2016.
The job will involve punching a new ‘fourth’ entrance through the exterior wall of the historic building and transforming the huge courtyard at its heart into a bustling town square.
The upper level of the landmark building boasts more than 300 rooms behind arcades and columns that will be turned into business units. The buildings middle floor has been earmarked for high quality retail use.
Gary Hughes, regional director at Graham Construction, said: “The Piece Hall is a historic and much-loved building which is part of the fabric of Halifax.
“The refurbishment will therefore be extremely sensitive to its heritage.”
He added: “The new build £9.25m library and archive, which Graham is constructing as part of the Piece Hall redevelopment, will also be a fantastic facility for the town within a thriving cultural quarter.