When should tooling of joints be performed?

Tooling of joints should be performed when the mortar is thumbprint hard. This timing is crucial because at this stage, the mortar has set enough to hold its shape and resist damage from the tooling process, yet it is still soft enough to allow for the desired profile of the joint to be formed effectively.

If tooling is done too early, when the mortar is still wet, it can displace the mortar and lead to an inconsistent joint appearance. Conversely, if tooling is postponed until the mortar is completely dry, it becomes very difficult to shape or tool the joint without cracking or damaging the mortar. Performing the tooling immediately after laying the blocks is also not ideal because the mortar needs to reach the appropriate firmness to handle the tooling action without deforming. Hence, the optimal moment is when the mortar has set to a firm yet workable consistency, typically described as thumbprint hard. This ensures a clean, professional finish that also helps improve the overall durability and weather resistance of the masonry.