The historic building of the State Library, built by Ernst von Ihne, is being remodelled into a modern, world-ranking library according to plans by the Stuttgart-based architect HG Merz. The project involves the refurbishing of the original building and construction of the new reading room, the open-shelf-library and the depository. The new, 250-seat central reading room, designed as a cube of light, will be built in the courtyard on the site of the original domed reading room which has been destroyed in World War II. Visitors to this "heart of the library" will have direct open-shelf access to almost 300,000 volumes.
Structural restoration of the Ihne building was successfully completed in 2001 after six years time. While the library continued its operations, workers replaced 2,700 pine stakes which had been severely damaged by an uncontrolled drop in the water table in the area around the library. In 2001 and 2002, 2,2 million volumes were shifted from the four out-dated depository towers in the courtyard to the storage facility at Berlin's Westhafen. The demolition of these towers in 2003 made way for the new central reading room, construction of which was made possible by the approval of funds in 2003. Building began officially on 9th May 2005, the laying of the foundation stone followed on 24th April 2006. On 5th February 2008, the topping-out ceremony for the new central reading room took place.
You can find further information about the construction activities on the website of the State Library Berlin (in German only):