The firm, one of the biggest two housebuilders in the UK along with Taylor Wimpey, claims to be the only national industry player with a major presence in London.
Edelman will support the company's sales-related comms work, which includes aspects of corporate reputation around its portfolio and support in terms of execution and sales.
Barratt London has been active for more than 30 years, working across all 32 London boroughs.
The company has a wide range of property interests in the capital, including regenerating obsolete housing stock, decontaminating and developing industrial land, and residential and commercial developments.
Current projects include the Renaissance in Lewisham, an urban development of 788 homes and leisure facilities. The firm is also undertaking regeneration projects in Hounslow and Barnet, and building new residential developments in Newham and Wandsworth.
The Edelman team, led by director Elizabeth Tagge, will be working with Gary Patrick, Barratt London's regional sales director, and Patrick Law, Barratt Developments director of corporate affairs.