Hello everyone, I am a returning member to InterNACHI. Glad to be back. I am interested in opinions regarding this thermal image. It is viewed from the interior, it is two exterior walls, poor delta t, probably 50 years old, 2x4 construction, stucco exterior. Sunny day, approx 16 celcius, both walls had sun exposure. Thanks in advance!
How could they at the same time and duration?
The sun was shining onto that outside corner and was on both walls when i went outside to check. I am not sure about duration and or which was exposed longer or more directly.
Do you know which direction the sun came from? Which wall was effected first? Do you have an image of the other cooler wall with out the warmer wall ( you showed one of the warmer wall )?
No, unfortunately I didn’t take a picture of the wall to the right. The signature appeared pretty normal to me. The wall to the left may have been in the sun longer as the sun may have moved from left to right. Moisture evidence was found in the left wall (probably from the top level bathroom located 20 feet to the left) as well as stucco cracks that flex under lateral pressure. Some of the IR pics appeared to have bagging signatures with hot spots above them.
When ever you find something like you did, move around, and check different angles. 
Absolutely! See something that doesn’t look right… take extra pics from all angles you can!
You cannot draw any meaningful conclusion about the structure from these images with the information provided. The only thing that I can tell is that the right wall exhibits a typical signature for an insulated wall with a warm interior and cool exterior. The left wall looks sun baked, like it had a long period of direct sun exposure before you took the image.
I can’t wait to get my camera and start doing thermal inspections. I’m excited to be able to see these issues and analyze the conditions. I’m sure exposure duration has something to do with the difference but can’t draw any conclusions.