The museum's courtyard was damaged during the Great fire of Hamburg in 1842 and fully restored in 1995. A glass dome over the inner courtyard was completed in 1989. The glass courtyard was completed by the firm of Von Gerkan, Marg and Partners. This provided more museum space without an actual new building, because it allowed increased use of the courtyard. The covered courtyard was actually envisioned, or at least considered, as part of the original design, however the construction of the covering was deferred. The design uses a steel gridshell.