Soane added an entrance porch and north and south wings to the nine-bay Mulgrave Hall (also referred to as Mulgrave Castle). He also built stables and made designs for offices. Soane's plans of the house in Plans, elevations and sections of buildings, 1788 (plates 31-33), show offices in the north wing and a library and drawing room in the south wing. The house today has symmetrical castellated wings with turrets at the corners, thus varying from the elevations in Soane's publication but corresponding to his plans.

Soane's existing drawings for the offices and stables do not show the executed design. Drawings are for an office court and stables built on axis and attached to the new north wing of the house, the stables surrounding a large court. The built stables, still standing today, are to the north of the house and consist of a long range with short returns at each end to enclose a small yard; this design was probably chosen to accommodate the steeply falling terrain. There is little evidence of an office block built by Soane although it is known that late 19th century offices were on the property in the same position as Soane's proposed designs, perhaps replacing Soane's buildings upon their construction.

Literature: J. Soane, Plans, elevations and sections of buildings, 1788, pl. 31-33; P. Dean, Sir John Soane and the country estate, 1999, p. 175

Madeleine Helmer, 2011