Rental expenses have to be claimed in the year they were incurred. Rental losses can be claimed against other income like employment income.
But first, you will need to determine if your expenses are current or capital expenses.
Here is more from the CRA:Rental expenses you can deduct: http://www.cra-arc.gc.ca/tx/bsnss/tpcs/rntl/bt/rprt/xpns/menu-eng.html
And this one from TurboTax Tips:
Dos and Don’ts: CCA for Rental Property Explained: https://turbotax.intuit.ca/tips/dos-and-donts-cca-for-rental-property-explained-6377