Selected Answers

From Warren Brand of Chicago Corrosion Group on December 1, 2016:
Great answer, Bryant! The mechanism that causes t ...read more Great answer, Bryant! The mechanism that causes the failure is the drawing of vapor molecules through the coating system (a semi-permeable membrane) to the "cold wall," just like a cold can of pop on a hot summer day, draws moisture out of the air. I wrote two blogs that expand on the process: http://www.paintsquare.com/blog/?fuseaction=view&blogID=162 http://www.paintsquare.com/blog/?fuseaction=view&blogID=163. I believe, however, that it's a fairly unusual mode of failure, and often used as a catchall.

From Bryant Chandler of Greenman-Pedersen, Inc. on November 29, 2016:
The cold wall effect occurs when there is a large ...read more The cold wall effect occurs when there is a large temperature differential between the substrate side and the coating side. Yes, it can cause premature coating failure. To reduce the chances of failure, make sure the surface to be coated is CLEAN. On metallic substrates, that means no salts or other contaminants and a good SSPC-SP 5 with proper angular profile. For concrete, make sure it is clean, verify low moisture and assure there is a proper ICRI profile.  Use a coating with a good perm rating to reduce moisture penetration. If possible, insulate the cold substrate side of the building to reduce the temperature gradient. And lastly, make sure the coating is applied when the substrate temperature is 5 degrees F above the dew point temperature.