I've been working on a high school building this month. The issue is water migrating through the mortar in the brick face of the building. This has been a problem for more than 5 years. I was asked to help provide insight into how the water is getting through a sequence of structures: Sheet rock over a vapor barrier over a concrete wall. Then there is an air gap followed by 3 layers of brick. The exterior brick has a ceramic glazing. The mortar is showing efflorescence and mortar is deteriorating.
I have used my drone and thermal imager to fly the walls and take thermal images. They indicated that the top 6 or so feet of the brick walls is cooler than the lower brick. This indicates there is likely moisture in the wall system. However, there are more issues. Imagine 1,700 students and the 100+ staff. If they are in the building 8 hours per day, they are exhaling and sweating about 600 gallons of water per day. That's 3.000 gallons per week. When teachers and students are in the building 180 days in an average school year, that's 108,000 gallons of airborne water per year.
What the Scan Reveals
This image above shows a darker band at the top of the brick wall. It indicates that the darker band is cooler than the lighter part. It will require destructive testing, but there is likely moisture in that area.
This is a stitched image taken with a drone utilizing a FLIR thermal imager. There are many anomalies on the roof system as indicated by the white areas, particularly in the lower left hand square area and on the main part of the roof. These will also require destructive testing to determine the extent of damage.