To handle the larger numbers and the increasingly diverse curriculum, major additions were made to the campus to the Laboratory and Science Block in 1969 and the Cavendish-Preparatory Department in 1972 (under the headship of Roy Haygarth, 1969-79).

Other major projects since then included: The Reiss Library (1975), The Haygarth Gymnasium (1979), and The Henry Hallett Art and Music Facility (1982).

At the same time, an extensive building programme was undertaken, adding a new block to Cavendish plus several additional classrooms at the main campus and including major reconstruction to the interior of "Woodlands."

By this time, the teaching staff numbered 59, and the School was led by its 6th Headmaster in 106 years, Mr. James Keith McPhee.

He sought to continue the pace of the School's advances whilst retaining both its high academic standards and its nurturing and caring atmosphere.

[citation needed] In 2015, former Headmaster, Ted Staunton returned to Saltus to guide the board of trustees in selection of a next Head of School.