The interior of the museum extension has an unconventional circulation, with the public initially traveling up levels before moving down through a journey of the museum spaces. Four levels divide the extension. The second floor is purely a multi-purpose space for the use of private events, with a glazed space cutting across Bull Lane to allow for views out across Rochester. The first floor holds a new permanent gallery and education centre, while also uniting with the existing exhibitions and Guildhall spaces. The ground floor has a new café located below the original Grade 1 Guildhall, and a temporary exhibition space at the rear which slopes down to the basement level, providing an expanse of space capable of displaying larger exhibits. The basement level provides more exhibition spaces, while also forming an internal link across Bull Lane via the underground pathway which has a glazed ceiling to unite with the projecting levels above. These four levels are all connected by views up and down, creating a more dynamic and interactive experience.
The angular design extends from the North side of the Guildhall Museum, not only reflecting the nature of expansion but also creating an iconic building for Rochester, attracting attention and drawing people into the museum. The form is in contrast to the existing building, and so from the High Street side a view of transparency is achieved by glazing the spaces projecting across Bull Lane; this also creates a view of activity above the lane which the public can see and walk below. Copper is the material used to clad the façade, with the intention for this material to naturally change and evolve over the years as platina forms due to oxidation. This façade is split by thin windows that cut across the building giving the appearance of the form cracking as it expands. The locations for the windows were inspired by studying the formation of Medway.
