Purcell has been the commissioned architect for all work at Knole for over twenty years, and a continuous programme of repair and conservation work has been in progress since the mid-1990s. Various parts of the house have been re-roofed and major repair projects have been undertaken in the Orangery and Long Gallery.
In addition to working for the National Trust, Purcell also carried out a significant programme of works to the private apartments, encompassing 52 rooms and 3 external courtyards. Work included the conservation, repair and reordering of the interiors, in addition to a new build extension and the re-presentation of a medieval roof space and historic Water Court.
The house has been largely re-wired, with conservation heating added to the display rooms. Comprehensive fire detection and compartmentation works, alarm and lightning conductor systems have also been installed.
A new staircase was designed to sit sympathetically within the traditionally panelled interior.
Knole retains the scale of a royal palace and is still occupied by separate households, with an impressive suite of rooms open to the public.