Moisture Verification (Core Cuts) in Flat Roof Inspections

This core cut shows a wet sample.

Once a complete evaluation has been performed to identify and mark all of the potential wet areas on the roof plan, it is time to determine the amount of moisture present in the marked areas. The non-destructive testing methodologies simply identify whether or not moisture is present during flat roof inspections. They do not determine the amount of moisture in the roof system.

To determine the true moisture content of a roof system, core samples need to be extracted from the affected roof areas. Core samples consist of cuts through the roof membrane down to the roof deck.

The sample provides an absolute test of moisture content and location. The core cut also permits the constituents of the roof system, and their condition, to be determined. Core samples may be weighed, dried and re-weighed to provide a quantitative measure of moisture content.

Core moisture content, measured 1" into core. The nuclear reading here is 21.