You can claim the maintenance of existing fences against the income you are reporting.  New fences are regarded as capital in nature and cannot be claimed as a current expense.  You will show this as a cost of additions and claim CCA if you choose to do so. 

Here is a list of CCA classes from the CRA : Capital cost allowance (CCA) classes - https://bit.ly/2J37ORB

Here is a list of Current versus Capital expenses from the CRA: https://bit.ly/2NRhY4B

And from TurboTax if needed - How do I enter my rental income and expenses in TurboTax? - https://turbotax.community.intuit.ca/replies/2647946

Did you managed to figure out the class? Was it class 6?

Fence for a rental properties. 

You would claim it as class 3. 

Class 6- is for buildings.

Thank you for choosing TurboTax.

@TurboTaxBrenda1  the rental building was build on 2018, so it don’t fit into class 3. Is class 3 still correct?

Please contact the CRA at 1-800-959-8281 so that they can direct  you.

Thank you for choosing TurboTax.