The six story water commissioners' building opposite City Hall, Belfast, built about 1870 for use as a linen warehouse, features heavily ornate stone elevations. Like most similar buildings it incorporated heavy load-bearing masonry on timber piles driven into the 'sleech' (estuarial silt). Marks and Spencer have traded on the adjoining site since the early 1970s. This building was acquired to allow extensions to their store. While the three upper floors aligned, lower floors differed widely in level. Schemes considered required reconstruction of the lower floors at levels to suit the existing store and a wider column grid for trading. The scheme adopted also included the retention of existing upper floors, strengthened, and the provision of a basement floor below the building. New concrete piles were sunk from within the building. A new steel frame was erected, a transition layer at second floor making all existing internal structure redundant. A contiguous pile external fence supported needles allowing the removal of all of the original foundations and excavation for the basement.