▁a ▁" un iverse ▁of ▁anonymous ▁trans ients ." ▁Since ▁traditional ▁class ▁roles ▁were ▁based ▁around ▁home ▁and ▁family , ▁residents ▁in ▁room ing ▁houses ▁did ▁not ▁fit ▁into ▁working ▁class , ▁middle ▁class ▁or ▁upper ▁class ▁patterns ; ▁instead , ▁they ▁were ▁in ▁a ▁sort ▁of ▁" social ▁and ▁cultural ▁lim bo ", ▁with ▁many ▁hoping ▁to ▁rise . ▁ ▁However , ▁with ▁the ▁bo om ▁in ▁housing ▁in ▁the ▁ 1 9 5 0 s , ▁middle ▁class ▁new com ers ▁could ▁increasing ly ▁afford ▁their ▁own ▁homes ▁or ▁apart ments , ▁which ▁meant ▁that ▁room ing ▁and ▁board ing ▁houses ▁became ▁used ▁mainly ▁by ▁post - second ary ▁" stud ents , ▁the ▁working ▁poor , ▁or ▁the ▁un emp loy ed ". ▁By ▁the ▁ 1 9 6 0 s , ▁room ing ▁and ▁board ing ▁houses ▁were ▁d eter ior ating , ▁as ▁official ▁city ▁policies ▁t ended ▁to ▁ignore ▁them . ▁By ▁the ▁ 1 9 7 0 s , ▁invest ors ▁started ▁bu ying ▁up ▁city ▁houses , ▁turning ▁them ▁into ▁temporary ▁room ing ▁houses ▁to ▁make ▁r ental ▁income ▁until ▁the ▁desired ▁price ▁in ▁the ▁housing ▁market ▁for ▁s elling ▁off ▁the ▁properties ▁was ▁reached , ▁a ▁gent r ification ▁process ▁called ▁" block b ust ing ." ▁From ▁ 1 9 7 7 ▁to ▁ 1 9 8 7 , ▁Montreal ▁lost ▁about ▁ 4 0 % ▁of ▁its ▁room ing ▁houses , ▁which ▁has ▁created ▁a ▁short age ▁in ▁afford able ▁housing ▁for