Northfield branch was built as a joint enterprise with the Electricity Department who owned a substantial plot of land surplus to their requirements after building a sub-station. The front portion of the building was built as one-storey only, in case this area was required for road widening at a later date. No such requirement was forthcoming and this part of Northfield was later bypassed.

The Ground Floor Plan shows the split of the property between the Bank and the Electricity Department's shop The location of the electricity sub-station (plus an extension) is behind the shop.

The single-storey feature of the building's design is detailed in the First Floor Plan (left) and the sectional drawing (above), and is shown in the photograph (below), taken before the Electricity Department's shop has been opened. Access to the Bank flat is by the door on the right of the photograph.