The contract is the second project awarded to GB by Signature in as many months.
GB has now started on site at the Marlow development which will provide 79 suites, 16 of which are specifically designed for dementia care.
The new home will be built over three storeys with a basement car park and include low carbon technologies such as gas absorption air source heat pumps.
Martin Smout, chairman and chief executive of GB Group said: “We are proud to be delivering Signature Senior Lifestyle their second care development and using our extensive expertise to make sure the residents live in a high quality building that provides a premium service where they can have both expert care and a happy, stimulating lifestyle.”
Wayne Pryce, director of development and construction for Signature said: “We look forward to working closely with GB to deliver another high quality home.
“Our residents are at the heart of everything we do and we focus on delivering the best home for them, from site acquisition through to building completion”
Work is due for completion in Spring 2014.