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Why a Vented Drained Cavity Is Your Best Defence

If you’ve ever heard the illustrious Dr. Joe Lstiburek speak, you will be well familiar with many of his catch phrases and quips. He uses them on repeat to educate audiences all over the world on best practice building science. His dry sense of humour amuses us building science enthusiasts no end and these genius simple phrases stick in our minds.

“Repeat after me. All claddings leak”

I can hear his voice clear as day in my mind!

The fact is that no matter how advanced the materials or meticulous the installation, cladding systems are not perfect and over the life of the building, will leak at some point. Whether it’s driving rain, wind pressure, condensation, or tiny imperfections at joints and penetrations, moisture finds its way behind the outer skin of the building.

Despite what we may think is the case, the cladding is not the water barrier and shouldn’t be treated as though it is. It’s an aesthetic. The durability of the building depends on the durability of the structure, and the key to durability isn’t pretending cladding won’t leak – it’s planning for when it does.

Enter the vented drained cavity.

A vented drained cavity is a small, continuous space between the back of the cladding and the water-resistive barrier (WRB). In the above image you can see there is a vertical counter batten which has been fixed to the stud, and then there is a batten on top of this which the cladding is fixed to.

This is deliberately designed to allow bulk water to drain and for air to circulate so that any moisture is quickly dried, whether it’s from cladding leaks or condensation off the back of the cladding.

It’s a simple concept, but its impact is huge because it doesn’t matter how wet your building gets, as long as it can dry.

So, are you currently incorporating vented drained cavities in your projects?

If you are – great! You’re well ahead of the pack and also ahead of the National Construction Code! This change in wall construction significantly increases the durability of your frame and reduces the risk of mould and rot.

If not, it’s worth asking, why not?

Whether you’re designing for climate or just aiming for best practice , a vented drained cavity the single easiest way to increase the health and durability of every house you build.

If you want to know more about how to incorporate this into your projects please each out via email or phone. We’re always up for a good building science conversation!

Also – who is Dr Joe Lstiburek?

Jess