The Greater Victoria Area was upgraded for seismic risk in 2012. For second floor additions, this means increased engineering requirements. Historically adding a second floor meant new point loads(downward loads) but now it means addressing lateral loads as well: spread footings, reinforcing steel in foundations, increased connections from foundation to framing and plywood sheathing added to existing walls to create brace panels.
Because of these new requirements, raising your home to add a second storey may be the more efficient solution. Drawbacks to raising your home and adding a level below is that the use of the upper level may need to change. This requires interior renovations which add to the cost. The best situation is when the upper floor continues to be used as is, with the new lower floor becoming a separate living unit. This way, the added unit can readily be built to conform with structural and other safety considerations.