Standing in the shadow of Grinshill’s rocky escarpment, Sansaw was formerly the seat of the Gardiner family for whom the present house was originally built in the late eighteenth century. The Gardiners were originally from Lancashire but were living in Shropshire by the early fifteenth century when Thomas Gardiner was recorded as of Sheinton, south of the county town. His descendant, John Gardiner (1595–1628), a Shrewsbury draper, who was married to Christabel, the daughter of Edmund Berkeley of Shrewsbury, bought Sansaw from Richard Russell in 1622.

The nucleus of the present house, a five-bay, two-and-a-half-storey, red brick block, with slightly projecting central bay embellished with stone window surrounds, was built for John Gardiner (d. 1801) in 1773–1775. John Gardiner had inherited the estate from his grandfather Thomas Gardiner (d. 1763). A contemporary painting shows the mansion in its original form, with flanking symmetrical single-storey pavilions to each side of the main block. Enclosures in 1783 established a larger park around the house, which was created when the western part of Sansaw Heath was added to the demesne.

With John Gardiner’s death, Sansaw passed through the female line to the Panting family. His cousin, Josina, daughter and co-heiress of Lawrence Gardiner, Prebendary of Lichfield, and his wife Anne, daughter of F. Blakeway, had married Stephen Panting, Vicar of Wellington. The Pantings’ eldest son, Laurence Panting DD (1767–1844), was the beneficiary and assumed the Gardiner name by Royal Licence in 1801.

On Dr Gardiner’s death, in 1844, Sansaw passed to his nephew, Robert Panting (d. 1880), the son of Thomas Panting of the Council House in Shrewsbury and his wife Mary Miers. Robert Panting assumed the name and arms of Gardiner by Royal Licence on inheriting his uncle’s estates and he married the heiress of the Kynnersley family of Leighton Hall (q.v.). He became master of that estate in addition to the Gardiner family’s other Shropshire property, Plas-y-Court, near Alberbury.