California Lathing and Plastering Contractor (C-35 License) Practice Exam 2026 - Free C-35 License Practice Questions and Study Guide

Assessing plaster crack severity focuses on both size and ongoing movement. Measuring width and length gives a snapshot of how big the crack is, but the critical factor is whether the crack is still moving. An active crack that continues to widen or propagate indicates ongoing stress, moisture intrusion, or substrate movement and requires a different, often more extensive repair plan than a static crack.

To evaluate properly, measure the crack width with a crack gauge or caliper and record its length along the crack path. Re-check after a period to see if there’s any movement—does it widen, lengthen, or show new cracking? If movement continues, this points to underlying issues that must be addressed (such as settlement, moisture problems, or structural stresses) and the repair should aim to stop further movement. If movement has ceased, the crack may be treated as non-active, with repairs focused on sealing and patching.

Color or pattern alone isn’t a reliable indicator of severity, and a visual inspection without monitoring movement can miss cracks that are still progressing.