I have one tenant that is harassing another tenant living above him on the second floor. The second floor tenant feels that his life is being threatened. What notice can I give the offending tenant?

You can give the offending tenant an N5- Notice to End your Tenancy For Interfering with Others, Damage or Overcrowding.  When you issue the N5, you have to be as detailed as possible when describing the issues and include dates and times when the incidents are occurring. The N5 is a 20-day notice but the tenants have the first 7 days to correct the problems, otherwise you can file an application with the Landlord and Tenant Board to go to a hearing and ask for the termination of the tenancy. If you have to go to the Board, it’s very important to bring witnesses to the hearing so you should speak with your other tenants and ask them if they would be willing to attend the hearing to testify to the occurrences.