The Smithsonian National Museum of American History (NMAH) in Washington DC, US, will close for two years to carry out an extensive US$85m (£45m, 66m euro) refurbishment.

The major renovation project will focus on three areas – architectural enhancements to the museum’s interior, construction of a gallery for the original Star-Spangled Banner and an update of the 42-year-old building’s infrastructure.

To prepare for the transformation, the museum will begin closing some of its exhibition galleries this spring and summer. The entire museum will close to the public on 5 September.

The transformation will include the construction of extensive 10ft (3m) ‘artefact walls’ on the first and second floors to showcase the museum’s three million objects and a Welcome Center on the second floor to improve visitor orientation.

The first floor will feature an exhibition gallery for the museum’s Lemelson Center for the Study of Invention and Innovation plus a new lobby for the 275-seat Carmichael Auditorium.

In addition, marble panels blocking the view to the museum’s third floor will be removed and a central core atrium with a new skylight to open up the building will be constructed. A grand staircase connecting the museum’s first and second floors will also be constructed while new entrance vestibules will be built to alleviate crowding.

Construction will begin in the autumn and the museum is scheduled to reopen by summer 2008.

Established in 1989, through an Act of Congress, the NMAH is an institution of living cultures dedicated to the life, languages, literature, history and arts of the native people of the western hemisphere. Details: www.americanhistory.si.edu

Photograph: Star-Spangled Banner gallery