Tate St Ives, the art gallery credited with helping to regenerate the southwest, will unveil its new look tomorrow (14 October) when it re-opens following a £20m redevelopment.

Jamie Fobert Architects’ cliffside extension has doubled the exhibition space, with the aim of better accommodating the 250,000 annual visitors to the Cornish attraction.

With an additional 600sqm floor space, the gallery will be able to host more exhibits, display more works and offers new educational and studio spaces, a collection care suite, where larger works can be handled, and a public roof garden.

The new building sits beside the original gallery, in a space carved out of the side of the hill. The gallery is lit from above by six large skylights.

The original building will be dedicated to modern art in St Ives and the new galleries will host seasonal exhibitions, opening with Rebecca Warren, an artist renowned for her clay sculpture pieces. In 2018, the galleries will be used for an exhibition of female artists inspired by Virginia Woolf.

“These beautiful galleries showcase some of the extraordinary artists who made St Ives their home across the twentieth century, as well as bringing some of the world’s most exciting contemporary art to Cornwall with Rebecca Warren's epic exhibition,” said Tate director Maria Balshaw.

“Tate St Ives is a much-loved part of the local community and of the Tate family, and I look forward to it playing an expanded role in Britain’s cultural landscape.”

Jamie Fobert, founder of the architecture practice, said: “The coastal setting and vernacular of St Ives have both influenced my approach to this work.

“Our focus was to create as large a gallery volume as the site would allow. Entirely excavated into the hillside, the new gallery extends, in a continuous journey, the existing gallery sequence.

"Six large light chambers capture St Ives’ particular light. On its roof, weaving between the light chambers, stairs and coastal planting create a new public space for the town."

Tate St Ives is thought to contribute about £11m per year to the local economy.