Telltale Monitoring

John V. Dinan Associates provides telltale installations and monitoring. We furnish personnel and equipment to perform accessible telltale installations and required monitoring services for various projects.

A telltale also known as a crack monitor is a basic joint movement indicator. This device can help determine if any pre-existing crack is dynamic or static and effectively measure the movement of cracks in masonry structures.

The telltale monitors are approximately 1.5 inches high by 7 inches wide. The crack monitor consists of two overlapping acrylic plates. One plate is white with a black millimeter grid, while the other is transparent with red crosshairs centered over the grid. The crack monitors are attached using epoxy adhesive.

Once the crack monitor is in position across a crack, the crosshairs shift vertically or horizontally on the grid if movement occurs, so that we can track crack movement. The telltale monitor measures horizontal and vertical movement across a crack on a flat surface to an accuracy of +/- 1.0mm and by interpretation to +/- 0.5mm.

In order to provide the most valuable report, we take macro-photographs which are used to analyze the data and determine if movement has occurred. These photographs are included in the final report. Since construction on all projects fluctuates the telltale monitors may be analyzed at different intervals. It will depend on the location of certain construction activities as well as the type of construction taking place and timing. We are happy to discuss all of these contributing factors in order to recommend the most effective schedule.