Please do not stop posting!
My observation about this section of the forum is that Snell uses it to promote and discuss their classes and webinars, but after reading your post, I re-read their heading on the forum, and perhaps I was not viewing its purpose correctly. My apologies, if so.
The other concern that drove my comment was your not knowing what dewpoint is. I regard that as a pretty basic concept.
A wet area will retain heat longer than a dry area during a cooling transient. It will be cooler during a warming transient. Your post was not clear about what the wall was doing at the time of the image. You indicated it was a west wall shot at 6PM. So, was it still in sun? Just out of sun? Out of sun for an hour or so? The interpretation of the image results depend strongly on the answers to those questions.
Here is a time plot of surface temperature of a stucco wall with good, wet, and delaminated areas over a 24 hour period. This is from a paper I presented. The curves are calculated. The points are data from a building obtained with IR. The upper graph is for a SE exposure, the lower for a W exposure. Note how the exposure shifts the curves. Note also how the curves cross - the wet area is warmest at night, but coolest under heating. Similarly, the delaminated area swings the most and is coolest at night, but warmest during the day.
Jack
Jack M. Kleinfeld, P.E.
Kleinfeld Technical Services, Inc.
Bronx, NY
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