What Is the Role of Rainscreen in a Building Envelope?

A rainscreen in a building envelope plays several roles. The rainscreen contributes to insulation, helps keep water from getting inside the building, and helps channel away any water that does get past the envelope.

What is a building envelope?

The building envelope is the part of building that separates the inside from the outside. The envelope keeps exterior elements out and also functions to regulate the air exchange, moisture levels inside, keep the interior cool or warm as required, and insulate.

What is a rainscreen?

The rainscreen is an added layer within the envelope. The rainscreen is behind the outermost shell, and it is a channel where any water that gets past the shell can be trapped and removed. In addition, the rainscreen has a thin layer of air which adds to its insulative properties and also helps it to dry out quickly if any water (rain) has passed through by virtue of a capillary break and extra ventilation.

The rainscreen exists in the vertical walls of a building only. It is an excellent way to manage buildings that struggle with water entering especially in a wet climate. It is an added layer of protection against the elements and insulation, and it is virtually invisible from the outside.

One other advantage of a rainscreen is that it is a mold preventative. If walls get wet on the inside, often we do not know about it, and it is difficult or impossible to dry them out. The rainscreen is a way to trap water and then channel it away from the building before it starts creating a mold problem.

Westerly Restoration provides building envelope and restoration services in Vancouver, BC, and throughout the lower mainland.

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