In a recent case the Ontario Superior Court of Justice declined to attach privilege to communication by e-mail between senior management and the H.R. department. The case is Guthrie v. St. Joseph Print Group Inc., 2018 ONSC 1411 (CanLII). 

In the decision the master stated  "If management seeks confidentiality in dealing with an employee, it should consult with counsel and not its HR department." 

The case is a cautionary note on how to handle communications where a dismissal or a law suit may be possible. It is a good idea to involve your lawyer in setting up your practices in communications.