Construction activities at Pfizer's Canadian head offices wereperformed in phases, without interruption at any time to the office environment. The first phase, totaling 75,000 sf of new construction and completed in 1999, consisted of 3 new office levels including one level below grade with a 3 storey atrium including a large skylight. In 2001 Reliance was retained to add a 25,000 sf4th storey above the 1999 office building including a new skylight. The last phase, completed in 2002, involved the renovation of the reception area, drop-off area and new landscaping; the office remained in full operation during the expansion.