How To Measure Thickness of Waterproofing Membranes

Installing waterproofing coatings both vertically and horizontally often requires specific thicknesses to ensure success of the application. Regardless of whether your product is spray, trowel or roll-applied, follow the steps below to properly read the mil thickness.

1. Apply your product to the proper substrate as instructed by the manufacturer. 
2. Insert your mil gauge into the wet membrane (estimating the mil thickness you applied to determine which side to insert)
3. Read the mil thickness by noting the deposit on the row of notches. Find the largest tooth/notch that is wet and the smallest tooth/notch that is not wet. The wet mil thickness lies somewhere between these values. 
4. Reinsert your mil gauge in different areas of the membranes to find the average thickness as application may not be consistent. 
5. If needed, reapply product to the proper mil thickness.

Watch the video below to see how the measurement works in action.