Volume 52, Issue 7

If you’re like me, you’ve been working on understanding the exact defi nition of a “rainscreen” and wonder why it hasn’t been more fully embraced as a common system in this market. I was first introduced to the rainscreen principle when I was in graduate school about twelve years ago and the first firm I worked for employed the philosphy in just about every building that was designed.
I thought I had a pretty good handle on it until I came across an article published by the Metal Construction Association entitled, “Understanding ‘The Rainscreen Principle.’  It says, of TWO different kinds of rainscreen designs,

“Both systems emply open joinery and allow a certain amount of water into the cavity area between the outer and inner leafs. Drained/Back-ventilated systems rely on the ventilation cavity to both drain and dry-out residual water. Pressure-equalized systems (PERS) employ drainable compartmentalization to limit water penetration during periods of pressure disequilibrium and to facilitate rapid pressure equalization.”

Unlike a conventional wall design which assumes a “single line barrier,” relying on sealant integrity, both rainscreen systems plan for the inevitable intrusion of water into the wall assembly and provide a pathway for that water to escape before building up and finding its way through the entire assembly. Not a bad plan for buildings that are seeing a rapid change in the name of energy efficiency and tighter buildings and the resulting periods of “pressure disquilibrium.”

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

w

Connecting to %s