With older buildings it is important to repair the parging quickly and properly. The cold Canadian climates can cause your parging to crack and deteriorate. If the water is allowed to penetrate behind the finish it can freeze and thaw causing even larger cracks.
The moisture from the water and ice can seep through the mortar mixture and finish, which then causes swelling from the inside. The damage starts with slight cracking, then progresses to a larger damaged area. Eventually, if not taken care of, the entire finish can fall off. This loss of parging will allow water to leak into the walls and floors of the building causing, rot and mold. Which can result in an extremely large repair bill.
When doing parging repairs, it is essential to remove the existing layer and put a new fresh coat on. Placing a new layer on top of the existing damaged layer will not fix the under lying problem and will be ineffective due to the existing cracks.
Repairing the parging when it cracks is important to maintaining the integrity of your building envelope, which is a key to protecting the structure and the interior of you home.