A WRB is variously called a Water Resistive Barrier (in the IRC) and a Weather Resistive Barrier (in the building science community); the difference is that weather contains water, but it also includes wind.
According to the International Residential Code (IRC), a Water Resistive Barrier (WRB) must be installed to shed liquid water that gets behind the siding and incorporated with horizontal flashings.
To bump up the WRB's performance, high-performance builders and building scientists call for upgrading the job description from a water barrier to also work as an air barrier. This typically includes taping the seams and sealing the edges. Though, all of those staples and siding nails throw a bit of a wrench in that task.
Here is a collection of animations, videos, and podcasts about WRB installation, air barriers, and liquid water control:
- Air Barrier Information
- House Wrap Installation
- Window Flashing
- Rainscreen Info
- Roof/Wall Flashing