#Leak - Structural materials

Infrared thermography photography by rain leak investigation of a two-story wooden apartment
The blue line which moves vertically and horizontally like the Amida lottery is a pillar, a beam, a muscle, etc.
It is wood which becomes the bone of the building.
Trees contain moisture, but if you are surrounded by walls and roofs as buildings,
As long as there is no leak or condensation, it usually dries.
Since the temperature inside is lower than the surface of the outer wall, wood is detected at a lower temperature.
There is a dark blue part in some places, isn't there?
What's this part?