Sir Frederick Snow & Partners Ltd carried out the structural engineering for the hospital's initial regenerative scheme in the 1960's, and continued to be employed for various works during the intervening period. The company was re-employed for Scheme 3, which is a major extension totalling around 178,000 square feet of floor area across five storeys.

Close co-ordination between structural and services design was essential, due to constraints imposed by the hospital layout and the extensive ceiling-space services typically required by hospitals.

To compensate for this, the structure of the building uses an irregular steel-framed grid system, incorporated within a slim floor construction. Poor ground conditions over approximately one third of the site also had to be taken into account. Foundations were varied according to ground conditions, and sized so as to minimise the risk of differential settlement.