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Having a long term goal toward net-zero housing within aluminium fenestration framing has
involves a multi-faceted approach which normalises become of paramount importance outlined by it's
the adoption of Passive House design techniques. This effectiveness in reducing unwanted condensation
approach will need to provide comprehensive guidance (Dunstan 1994). This technology is by no means new,
to ensure dwellings are free from condensation and or complicated. The simple adaption of a thermally
mould, whilst also being more energy efficient and broken strip between the outer and inner framing
thermally comfortable (Dewsbury et al. 2016). denies the movement of water vapour through
the framing system, this movement of vapour is
called diffusion (Nath et al. 2020). The accumulation
ROLE OF DESIGN of moisture within the interior environment is
PROFESSIONALS mainly due to diffusion, thermal bridging and air

leakage (Lionel 2005). Not only is this prevalent
Building designers, architects, engineers and within aluminium fenestration systems, but there
interior architects play a crucial role in adopting are many design features that create thermal
and becoming more aware of "scientifically bridging. Some of the most common architectural
correct" building design (Nath et al. 2020). It is features on buildings such as "cantilevered beams,
only through endeavouring to exceed current concrete balconies, roof penetrations, parapets,
code expectations that the canopies, spandrel glass and
accumulation of moisture There is a confusion other ornamental architectural
and mould growth can be features'" are often limited in
eliminated. According to between vapour- application due to their ability to
Dewsbury et al. (2018), in create thermal bridges (Nutcher
Australia, there seems to 2015).
be a confusion between tightness and
vapour-tightness and air-
tightness, something which air-tightness
has been proven critical
in allowing infiltration to
occur. So if the sole focus Dewsbury et al. 2018
lies entirely with insulating
and draft proofing our
building envelopes, this
does not necessarily eliminate vapour permeability.
Findings by Nath et al. (2020) demonstrate that
everyday household tasks such as showering Figure 8 Thermally broken and non-
and cooking, can lead to levels of up to 95% -thermally broken awning
humidity in habitable spaces. Combine the high
level of indoor humidity with thermal bridging Within Australia, the concept of thermal bridging
through the building envelope, poor water is not very well understood in the design and
vapour management and ventilation, the perfect construction professions (Dewsbury et al. 2018).
conditions for condensation and mould growth An example of this is the significant amount of
are created (Dewsbury et al. 2018). With the need air changes in new homes. "The Passive House
for new homes in Australia requiring substantial standard requires 0.6 air changes per hour when
amounts of artificial heating to remain thermally a 50 Pascal pressure difference is applied between
comfortable, this creates significantly more the interior and exterior environments (ACH50)"
water vapour in the warm interior environment, (Nath et al. 2020). In 2017, Ambrose and Syme
compared to the cool exterior. What then occurs measured 39.0 ACH50 in new homes in Perth
is a significant differential in vapour pressure and and Sydney, these results indicate a significant
potential for these water vapours to condense opportunity for thermal bridging and mould
on cooler surfaces (Nath et al. 2020). An example growth. Not only can thermal bridging occur within
most commonly seen is the condensation build solid elements, it can be also "be caused by the
up on aluminium non thermally broken building leakage of cool air inward or warm air outward"
systems. The development of thermal breaks (Nath et al. 2020).