Water has three phases: solid, liquid and gas/vapour. Of its three phases, liquid and vapour (when it condenses) are the most invasive and destructive elements to a building.

The root of most building problems is tied to moisture:

• Damp or wet basements
• Leaks
• Rotting wood
• Nail pops
• Mouldy bathrooms
• Moisture in attics

How Water Moves

Water movement occurs based on four factors:

• 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

Moisture comes from four sources:

Inside Sources:

• Lifestyle - Firewood, showers, bathing, cooking, hobbies, plumbing leaks

Outside Sources:

• Surface water - Drainage of rainwater, melted snow, roof water
• Ground water - How the foundation interacts with water in the ground and how it is separated
• Leaks….

Why Control Moisture Flow?

Understanding moisture is critical to the successful insulation of buildings. Controlling moisture flow is important for both durability and comfort:

Durability benefits Protection of building materials from moisture damage and expensive repairs

Comfort benefits Greater control of indoor humidity levels

Not managing moisture can lead to many negative impacts on homeowners including:

• Flooded basements / crawlspaces
• Attics get wet and/or frost in winter
• Swelling building components
• Condensation on windows
• Dampness --> mould --> health impact