As noted in module 1, the terminology for "control layer" and "barrier" or "barrier system" are used interchangeably throughout this course. On-site the terminology will most commonly be "barriers". It is important to keep in mind that the main purpose for these barriers is to control the movement/flow of moisture, heat, vapour, and/or air.
This module focuses on what the control layers do, how they work, and what criteria they must meet. The approaches/systems used to install these control layers will also be discussed. Installation methods will be covered in module 2.4.
The water control layer will be discussed in terms of above and below grade, since different materials are used to control moisture in each situation depending on the exterior grade placement.