Photo Source: Summerhill

How Does It Work?

It prevents the infiltration of water carried by gravity or rain/snow driven by wind, through the control layer. Above grade exterior water tries to enter the building envelope by gravity, capillary action, and pressure differences. The water control layer is engineered to prevent water penetration from occurring. It is also designed to allow the wall assembly to dry out when it gets wet.

Although we will not be focusing on flashings in this course it is important to note that they form a very important part of the water control layer. Flashings are used to direct bulk water out of the wall system and away from the building and work in partnership with the weather barrier system.

Criteria:

• Installed towards the exterior
• Resistant to air flow
• Able to shed rain or snow
• Able to withstand the forces (weather) that may act upon it
• Durable during construction and over expected building life