- Gravity
- Drainage of rainwater, melted
snow, roof water, other bulk water (lack of or improperly installed
flashings)
- Capillary
Action
- Or Wicking of moisture through
porous materials due to surface tension causing natural
suction
- Diffusion - also called
Osmosis
- When water passes through a
semi-permeable membrane into an area of lesser concentration thus
equalizing the concentrations on either side of the membrane
- Air
Movement
- Water carried in the air by air
movement due to pressure differences