http://www.spanishpropertyinsight.com/buff/2010/03/01/new-figures-tell-tale-of-property-boom-and-bust/#more-4046
Having just read the above article about housing starts/completion and the projected over-hang, I think the estimate of when this overhang will be consumed is going to be a long time.
New home formation was estimated around 200,000 in the boom
Holiday homes 200,000
Given the ecomomic crisis and housing being many years away from being investments, second/holiday home demand has completely evapourated. New home formation will significantly reduce as immigrants have stopped arriving and many are going home. In fact those leaving are freeing up new housing stock!!
If you put the figures for demand at
50,000 (second/holiday homes)
100,000 (New home formation)
And 1.5 million unsold homes
Then 10 years with no other homes built during the meantime.
Of course if the population does not grow and Spain has the lowest birth rate in Europe, then maybe that new home formation could be zero, since as a new home is formed an old one is lost (New couple verus old couple dying). Maybe this overhang will never be consumed completely!!
I wonder how this is going to affect Spain recover from this economic crisis.