Australian Passive House designer Matt Purves posted online some intriguing photos of bespoke doors he built himself from leftover spruce wall panelling. These were for his home in Tasmania, which is targeting Passive House Plus certification. Ventilation systems need air to be able to move freely between rooms even when doors are closed. This is most often achieved by the use of door undercuts, but they bring their own problems with noise travelling between rooms.
Matt’s doors have been constructed to allow air to pass through them, but not noise. This is not a readily replicated solution because it was enormously time-consuming but it vividly demonstrates a high-end alternative to door undercuts. His description of the solution was posted to a Facebook group only accessible to members, so he’s kindly agreed we can republish his comments and photos here, as follows:
We didn’t want architraves and planned to utilise the scrap timber we had that matched the spruce wall panels, to create a more seamless interface at door thresholds. This gave us 90mm of depth to play with in the doors to easily create a ventilation channel. However, with veneers and a more typical hollow core door, this could be executed in a 40mm door as well.
We calculated 150cm² was the minimum aperture sizing to move 40m³/hr of air. The aperture we implemented is closer to 320cm². In operation it is easily sufficient and provides silent transfer of air between rooms/zones.
Obviously not an option for all circumstances, as it would be cost prohibitive for a lot of projects if these were outsourced to build or charged out by the builder. These were incredibly time consuming to build—although for us, it was a cost saving measure as the 2400×860-960mm doors became essentially free, bar some glue, sandpaper and a lot of time. Hinges were the only hardware required, given we built in handles. But if the circumstances permit, this is an alternative option to add to the existing remedies.