Flannery spent nearly 20 years at ISG, the past eight years in various director-level positions at ISG, where he led projects across both the private and public sectors.
He also joins the construction board of Wates in the new role.
A Wates spokesman said: “Wayne’s extensive background includes significant work on public sector frameworks, which will be invaluable as he joins our leadership team and takes on this new role.
“As part of his responsibilities, Wayne will also join the construction board, contributing his strategic expertise to help drive growth and innovation in the division.”