Aiming for Passive Home standards after the project has started? Here’s how Aero helped do just that!
When Auckland’s Respond Architects heard that their client wanted to achieve Passive Home standards for a multi-dwelling development in Auckland’s Mangere Bridge not just after it had been designed, but after the build had started, Aero stepped up.
An extremely high airtightness level of 0.6 ACH is central to Passive Home certification. For that reason, architects and builders aiming for the rating consider airtightness from the start – long before the first concrete is poured.
Even with the challenges involved, developer Jasnish Gujral of Nest and Invest says it was the increased comfort and quality of living that convinced his team to make the shift to Passive House. “We said yes, let’s upgrade our building and see if we can give buyers the best living conditions possible.”
“Let’s upgrade our building and see if we can give buyers the best living conditions possible.”
Jasnish Gujral, Nest and Invest
“When the client became interested in aiming for Passive House for this project, we sat down and talked to them about the certification, the benefits and how to achieve it,” Respond Architects explain. “We then did the energy modelling for all 15 units to determine how we could achieve this.”
While modifying the existing design and build plan to achieve the higher standard worked on paper, reality didn’t quite match up.
Despite top-class work from the builders, developers and architects to pivot to the higher standard after the foundations had been poured, three of the development’s 15 homes were still falling short on airtightness.
When a blower door test on the first home showed lower airtightness than the standard requires, the build team were faced with a real challenge.
That test revealed junctions in the 2-storey semi-detached units that were making it hard for some of the homes to meet the standard, especially in the midfloor, staircase and intertenancy wall.
The team’s first response was to identify and plug every gap that the blower door test revealed, but they soon realised that this wasn’t the best way to tackle it. On the architects’ recommendation, the developer approached Aero.
We proposed using our AeroBarrier air sealing system to increase the airtightness of the homes — an automated system using a modified blower door assembly to pressurise the buildings and seal hidden air leaks by distributing a low-VOC sealant that is directed straight to the gaps.
“To avoid spending significant amounts of time trying to find these little leaks, it was going to be easier to use AeroBarrier.”
Respond Architects
We first tested the AeroBarrier system on the first unit, which needed to achieve a result of 0.6ACH. Following a successful result, the system was then used on two more units that were struggling to hit the airtightness target. Completing the air sealing process took less than a day on each of the homes. Following the AeroBarrier air sealing all three units passed an independent blower door test, confirming the 0.6ACH airtightness result needed for Passive House certification.
While most architects would recommend setting a Passive Home goal before design and build begin, this project is proof that a flexible attitude, a committed developer and a little help from Aero can deliver on the very highest airtightness standards.
