Barrier vs Rainscreen Facade Systems

Introduction

Exterior wall assemblies are designed in limitless ways, with immeasurable different amounts of materials. However, all of these assemblies generally conform to one of two different strategies to prevent water from getting into the building; the barrier concept, and rainscreen system.

Historically, the barrier strategy was the only real way to prevent water infiltration. However, over the years the rain screen system has been developed which provides better performance and reliability, especially over time. Some systems and technologies, which may have previously been implemented as a barrier, have been further advanced and designed to now be rain screen systems.

Façade vs Facade

Facade is derived from the French “façade”, which means "frontage" or "face".

Barrier Concept

Strategy that all exterior surfaces should be completely sealed to stop any water from penetrating. The barrier against water intrusion is the exterior wall itself.

Problems and Issues

This historically has caused a lot of issues because inevitably, the barrier (wall) would crack, seals break down, or some other opening would occur in some way. The barrier system is designed to not let any water in at all; so when water ends up getting past the barrier, the water/moisture has no way to navigate ‘back out’ from behind the wall. This ends up causing damage.

In theory this means that the wall needs to be built ‘perfectly’ (and stay perfect) for it to function without any issues. However, even when a wall is built perfectly, the exterior elements will wreak havoc over time, such as thermal expansion/contraction, UV breakdown, and other numerous issues exterior materials have to consistently resist. This means that the barrier system will always eventually fail.