Soane sent John Sanders (pupil 1784-1790) and Robert Woodgate (clerk 1788-1791) to the newly-acquired property on 28 August 1788 to make surveys of the house. The pupil and clerk drew up the the plans from 29 August to 1 September.

The existing house is a modest five-bay Georgian building. Symmetrical curved screen walls, one concealing an office wing, are positioned to either side of the north entrance front. Soane's pencil amendments to drawing 2 show alterations to the offices. The rooms of the house, with their dimensions, are noted in feint pencil on the drawing. A list in the upper right-hand corner of the sheet on drawing 2 notes prices of building materials, including lime, sand, scaffolding and slab.

Drawing 3 includes preliminary rough designs for the additions, shown in feint pencil on the front elevation and attic plan. Already Soane determines that the new building will be 3 feet 6 inches taller than the existing structure. Preliminary pencil alterations to the plan show a staircase added on the east side of the house (as in later designs, drawings 10 and 13), with the room to its south enlarged and a closet added.