If there was trend that sums up the excesses of the Celtic Tiger bubble this is it: between 1991-2011, for every 1000 new households, 1,493 housing units were built; for every 1000 new people added to the population, 874 housing units were built.
According the Dept of Environment data between January 1991 and December 2010 there were 933,404 housing units built in Ireland.
As recorded in the Census 2011, between April 1991 and April 2011, households grew by 625,124; the population grew by 1,062,533 in the same period.
Even accounting for obsolescence and replacement (approx 72,000 units based on the difference between housing stock change in the 91/11 censuses and total constructed units), we were building way in excess of demand, hence the high level of present oversupply.
Rob Kitchin