Comparing the Three Systems for Rain Penetration Control: Storage, Drained Rainscreen, and Perfect Barrier

Rain Penetration

Rain control is the most important function of an enclosure, since it directly correlates to a building’s longevity. The number one factor for effective rain penetration control is good building design. Most rainwater can be deflected off of a building through use of architectural features or landscaping. However, rainwater management features are still vital in managing the remainder of the water.

There are three different types of rain penetration control, but only one clear winner: drained enclosures.

Storage approaches to rain control do exactly what the name implies: store rainwater in the enclosure, then remove it by drying. The storage capacity of the construction materials and drying conditions function as limits on this type of system, so naturally it’s only a practical approach in certain climates.

Perfect barrier systems create a single, continuous, watertight plane much the same way that air barriers create an airtight plane. However, it’s very hard to create ‘perfect’ anything, and perfect barrier systems often use drained walls or drained joints. As technology improves, perfect barriers may become a better option, but in today’s world, they are hard to achieve and maintain, especially when using many materials.

Drained enclosures provide drainage for rainwater that penetrates the outer cladding. They are effective for claddings that leak, like brick veneer and stucco. Drained screen systems are both economical and durable; most wall system failures happen because drainage was not designed or installed.

A conjunction of skilled design and construction along with a carefully-chosen control system is necessary to ensure a building’s durability. No one wants to build something that will only last a short while, especially when there are alternatives.  Uncontrolled water within the enclosure is the most significant factor in building degradation which makes the rain control system critical.