however, with the boom in housing in the 1950s, middle class newcomers could increasingly afford their own homes or apartments, which meant that rooming and boarding houses became used mainly by post-secondary "students, the working poor, or the unemployed". by the 1960s, rooming and boarding houses were deteriorating, as official city policies tended to ignore them. by the 1970s, investors started buying up city houses, turning them into temporary rooming houses to make rental income until the desired price in the housing market for selling off the properties was reached, a gentrification process called "blockbusting." from 1977 to 1987, montreal lost about 40% of its rooming houses, which has created a shortage in affordable housing for low-income people.