The cost of home ownership increased slightly in Manitoba and the rest of Canada in the last three months of 2009. And the cost is expected to keep rising this spring as buyers scramble to close deals ahead of expected higher interest rates, new mortgage rules and new taxes in the key national markets of B.C. and Ontario, according to RBC economist Robert Hogue, author of the bank’s quarterly Housing Trends and Affordability report. Even though house prices were up just about everywhere in Canada in the fourth quarter, affordability declined only modestly. “That is largely because of exceptionally low mortgage rates,” Hogue said. The Bank of Canada has pledged to keep its key overnight rate at 0.25%, where it has been since last spring, until the end of the second quarter. But economists anticipate it will begin rising as early as July, which will further erode housing affordability.