Concrete block wall parging
Parge the outside face of concrete block walls with at least 6 mm (1⁄4 in.) of Portland cement plaster, forming a cove on the outside perimeter joint between the footings and the wall (Figure 45). Dampproof the wall by applying at least one heavy coat of bituminous material over the parging up to the proposed ground level. For added protection where large quantities of water accumulate in the soil, waterproof the wall by mopping on two layers of bitumen-saturated membrane and cover it with a heavy coating of bituminous material. This covering will help prevent leaks if minor cracks develop in the blocks or joints between the blocks.
Source : Canada Mortgage and Housing Corporation (CMHC)