What is the role of aggregates in a hard coat stucco system?

Aggregates – also called plaster sand when used for stucco – give cement plaster the body to be able to work in three dimensions. When the aggregates are graded and proportioned correctly – and combined with portland cement/lime or masonry cement – the matrix cures into a hard and durable wall.

Properly graded and proportioned aggregates save you money because they provide the maximum yield for a stucco base coat.