To limit the probability of inadequate provision for drying, which could lead to the entrapment of surface water or water from the ground transferred through masonry or concrete, which could lead to wood decay, which could lead to an inability to resist expected gravity or lateral loads.
For floors and elements supporting floors, this is to limit the probability of:
This is to limit the probability of excessive deflection or vibration, which could lead to persons losing their balance, tripping or falling, which could lead to harm to persons.