"In a recent six-month period about 70 per cent of all
   detached homes sold on Vancouver’s west side were
   purchased by Mainland China buyers..."

You get echo effects from places like Vancouver. Wealthy foreign buyers use high end real estate as a bank account increase the prices of top of the line housing significantly. Wealthier natives (Dentists?), now priced out of the highest end go down the scale and start purchasing lower end stuff with more money, increasing the price for everyone in a domino effect.

Government, not wanting the housing market to go down, create laws to allow subprime mortgage lending and buyers buy houses without real limits on price, and the middle class can now keep up with the price boom.