In extending the book shop premises out into a narrow, enclosed backyard, a main consideration was maximisation of daylight penetrating into the store, to create a light, open structure. Transparency and lightness of form were aspects also evident in the staircase, a self-supporting steel unit slotted into the airy space between galleries. The points of support for the supporting steel bars are easily distinguishable. The balustrading acts as a lattice girder, thus enabling a slimmer general stair profile.