Why intelligent membranes are important

Why should you wrap your home internally?

Airtightness is one of the key principles of any certified Passive House so it is essential you get it right. Our internal wrap is more than just a membrane to achieve airtightness! It actually plays an important role in moisture management within the structure by improving the capacity of the building assembly to dry out.

We refer to our internal wrap as an "intelligent membrane", because it really is a brilliant piece of technology.

These membranes provide a seal against moisture in winter, but in summer, it facilitates drying out as the molecular structure becomes more open. Their vapour resistance changes seasonally, depending on temperature and humidity.

During winter, the membrane has high vapour resistance - assuming it has been carefully installed. This prevents the majority of moisture from passing through internal surfaces, building up in the insulation layer and potentially leading to interstitial condensation as it cools towards the external side. 

In the summer months, when the vapour pressure is higher externally than internally, the vapour resistance of the membrane dramatically reduces. This encourages any moisture that has built up over the winter months to escape back through the internal surfaces and be ventilated away from the structure. 

Using an intelligent membrane such as intello, it lowers the risk of interstitial condensation during the winter and sweating during the summer.

When you install an intelligent membrane, it should always be accompanied by some form of mechanical ventilation. In our case, we always pair it with an HRV to remove as much moisture in the air, further limiting the risk of condensation and mould growth.

The last two slides show how important this intelligent membrane system works on a timber structure. This has been taken from the Proclima study by Jesse Clarke. It simply shows that with a quality WRB and intelligent membrane, the chances of mould developing in the structure are next to none.

This study outlines construction solutions to achieve low-energy, healthy and durable housing for future generations and is honestly one of the best things we have ever read. As a sustainable builder, we think this study should be ready by everyone in the industry as it provides you with the knowledge and information to build a healthy home. 

Source: An Australian Based Study on Airtightness and Moisture Management
Jesse Clarke

Proclima

This study shows the importance of moisture management on not only passive house homes in Melbourne, but any home in Melbourne.