The Standards and Guidelines for the Conservation of Historic Places in Canada consider conservation according to three types of treatment: preservation, rehabilitation and restoration.

A particular treatment is selected based on the primary objective of the conservation project and the heritage value of the place.

Preservation

Action or process of protecting, maintaining and/or stabilizing the existing materials, form and integrity of a historic place or of an individual component, while protecting its heritage value.

When to use preservation as the primary treatment:

• When heritage values related to the materials dominate.
• When the materials, features and spaces are essentially intact.

Rehabilitation

Action or process of achieving a continuing or compatible contemporary use of a historic place or of an individual component, through repair, alterations and/or additions, while protecting its heritage value.

When to use rehabilitation as the primary treatment:

• When character-defining elements have to be repaired or replaced.
• When alterations or additions are necessary for a new or continued use.

Restoration

Action or process of accurately revealing, recovering or representing the state of a historic place or of an individual component, as it appeared at a particular period in its history, while protecting its heritage value.

When to use restoration as the primary treatment:

• When the significance of the place during a particular period in history significantly outweighs the potential loss of existing materials.