Newly unveiled designs Brooks + Scarpa and KMF Architects for a $20m (€18m, £16m), 40,000sq ft (3,700sq m) expansion of Florida's Mennello Museum of American Art show a mixture and merging of indoor and outdoor spaces.

Integrated with the existing 12,000sq ft (1,100sq m) museum building, the new structure mixes spacious, naturally-lit indoor exhibition rooms with terraces, covered outdoor spaces, open concourses and pathways connecting them with the green and lakeside surroundings of Lake Formosa.

There are indoor and outdoor multipurpose spaces for events likes weddings, education visits and conferences, interior spaces and walkways with floor-to-ceiling glazing and a sculpture garden for visitors to walk around. Large pale-coloured expanses, both inside and out, are offset with warmer timber surfaces.

Lawrence Scarpa, principle of Brooks + Scarpa, said: "The Mennello Museum's design is both futuristic and timeless. The design mirrors the objective of the artwork inside: It tells a story and furthers the Museum's mission to be a place of education, culture, and inspiration.

"More than just a building, it is a civic place for social interaction, bringing people closer to art, each other and to nature, providing an opportunity for new, immersive, art experiences. The building is organized as a series of highly engaging spaces where the Museum's mission of using art to connect people to the world around them can unfold."

A completion date for the project has yet to be confirmed.