Traditional construction would commence with excavation down to the lowest basement level and work up on a level by level basis to ground floor and then to the superstructure.

Top down construction, the method used by Byrne Bros, typically gains significant time over the traditional building sequence by minimising the below ground construction works prior to commencing the superstructure. The remainder of the basement levels are then constructed in parallel with the superstructure construction in a top down sequence.

Top down works typically consist of access through a completed ground floor for excavation and construction of the basement floor levels working in sequence down to the lowest basement slab level.