Troubleshooting condensation on interior walls

In a building that was built in 1964 on concrete slab, there are two rooms on the first floor and another room on the second floor that condensation builds up on the interior walls. There is no plumbing leak or roof leak. The backyard is not landscaped, and dirt comes up to the stucco.
I have been asked to troubleshoot the cause of this condensation. How can I use a thermal imaging camera to figure out what causes condensation on the interior walls?

G A, This is not a DIY forum.

I would recommend that you take classes to understand thermal imaging before doing work for people where you are charging them good money.

There is Flir, Infraspection and Monroe that I can think of, off hand.

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Thank you. I am doing this to help my parents. I am not charging them.

You don’t need thermal imaging to diagnose the issue.
There are many pieces of data missing from the equation; moisture and environmental readings, temperatures, etc. etc.

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Yes, Dom, dew point would be a good start, among others thing like you mentioned, etc.

Good testing G A! :smile:

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Hi G A,
In addition to the excellent advice already given, some of the factors involved may or may not include: seasonal variations, local climate, sun exposure, weather, excessive cooking, wall materials, vapor barriers, insulation or the lack thereof, etc.

When I used to trouble shoot building concerns I never assumed any pre existing conditions - like your statement that there are no leaks. That may very well be, but starting with a mental blank slate worked well for me. I would make observations, then try to logically confirm or rule out all of the preceding, and more. A moisture meter may be helpful. Asking the owners observation of the patterns can help, if accurate, but their observations can be incorrect, and they see what they think it is.

Best wishes.


I remember a condo I remodeled a few years ago, where the HVAC subcontractor miscalculated the tonnage of the split system. I questioned him why every other apartment had 2.5-3.0 ton, and he was installing a 4-ton.
Anyway, in one hot room (large sliding glass doors which were very poorly insulated which the homeowner wanted to keep, south-west exposure) there was visible condensation streaming down the wall below the register every afternoon. This started after the new larger system was installed.
We quickly figured that a combination of factors were contributing to the problem.