No.  Infrared cameras can only see the temperature difference on surfaces.  The anomalies and different materials under the surface will change the temperature of that surface.  With proper interpretation of the infrared thermograph, problem areas can be diagnosed.

No.  Infrared cameras are totally non-invasive. They only see radiant heat and cold from surfaces.

The water will not show up if the conditions are not correct. If the outside and inside of the building is at the same temperature, water behind the wall will look the same to an infrared camera as the wall itself. On the other hand, if it is cold outside and the house is warm inside, the water will be evaporating which will make the water cooler. This cooler area which will show up nicely on an infrared camera. After spotting possible moisture, we use a non-invasive moisture meter to confirm the location is moisture.

Yes it can.  The principle of looking for this kind of leak is different because we will not have evaporation helping us make the water show up as cooler areas. Instead we use the principle of thermo loading and how it affects different materials. The fact that water will hold temperature better than roofing materials and insulation, will make it take longer to warm up or cool down. Using the thermo loading of the sun shinning on the roof, warming the roof and moisture during the day, we use the infrared camera after the sun goes down.  When the roof starts cooling off, the water will show up on the infrared camera as warmer areas. This process can also be done in the late morning because the water will take longer to warm up then the roofing materials.  At this time the water will show up as cooler areas as the roof starts warming up from the sun.

Yes it can with the correct conditions.  If the area is heated 10 to 20 degrees above the slab temperature for a day or two, then the wet areas should show up cooler. This is because the water will transfer the heat away from the slab quicker then the dry areas under the slab. These cooler areas will show up on the infrared camera.

What the infrared camera will see is the cool areas on the wall or trim surfaces caused from the cool air. This shows up as streaks caused from the air movement across the surface.

Yes, very well.  Most problems dealing with electricity causes heat. These problem areas show up very well with the infrared camera. The camera can also see problems with different loads showing up as warmer of cooler areas when they should be the same as the other common loads, wires or equipment.