Rick Mather Architects received the accolade in the NLA Conservation and Retrofit category. Judges remarked that they could "see the project spinning off into a lot of secondary economic benefits," and that the scheme will transform a building that "desperately needs to be brought back into decent use."
The council's £30m regeneration project will bring back the best original features of the 1962-built Fairfield Halls and will transform College Green and the car park below it into a new contemporary gallery.
"It's fantastic to see the plans we have had drawn up for the Fairfield have been given a professional seal of approval from experts across the globe. We are just two years away from opening the doors to an exciting new chapter in Croydon's cultural future."
Councillor Alison Butler, deputy leader and cabinet member for homes, regeneration and planning
Stuart Cade, Partner at Rick Mather Architects, said "We are delighted that our work at Fairfield Halls and College Green has been recognised by New London Architecture in the conservation category.
"This project provides a fantastic opportunity to build on the cultural legacy of Fairfield Halls, celebrating the strong original architecture, and developing high quality designs for new and improved facilities for future generations of Croydon residents to enjoy. The proposals make the activity within the buildings more transparent, improve the public realm to make the place more safe, more accessible and brought up to date.
"The aim is for the project to become a catalyst for wider regeneration, through the transfer of an underutilised space, to a new arts and community facility for Croydon. "
Deputy Mayor for Housing and Residential Development, James Murray, said: "Great architecture must marry design and function, helping us build a future London we can all be proud of. All the projects recognised at this year's awards make an important contribution to capital's built environment and many have been delivered collaboratively with boroughs and City Hall."
Photograph shows: The Fair Field team receiving the award at Guild Hall. Photography Credit Agnese Sanvito. Proposed view of restored Park Lane elevation, with activated frontage, improved transparency and a new forecourt welcome. Image Credit Rick Mather Architects.