Specifying for Performance

Even the very best designs will not perform unless the materials and systems specified support the intended performance. Every element needs to be carefully considered and unfortunately, we cannot rely on the Building Code of Australia or other compliance measures (Nathers, Basix) for guidance as to best practice and what will lead to a comfortable home that is cool in summer and warm in winter.

So what is the difference between the minimum construction standards and best practice? This can be illustrated through a couple of recent projects we have specified. Starting with glazing, regulation allows for simple aluminium frames and single glazing while we recently specified windows that cut heat loss in winter by the equivalent of running 3 2kw heaters flat out while in summer, the heat gain through the glass was cut in half. On another project, proper simulation showed that we needed almost exactly double the amount of insulation that regulation required; insulation that works both ways keeping heat out and coolth in during summer and keeping the cold out and warmth in during winter.

Condensation is another major issue that plagues homes in Australia, resulting in both visible and hidden mould, with the resulting health issues. Condensation is most obvious on poor quality windows, but the biggest issues can be found within the fabric of the external walls, where unseen condensation results in ideal conditions for mould to grow. In some cases, it leads to visible mould on walls and ceilings, but in many situations, the mould cannot be seen, despite it doing as much or even more harm than what can be seen¬† Again, regulation doesn’t help us, so we need to have a proper understanding of Building Physics in order to be able to specify waterproof and vapour permeable membranes and ensure they are positioned correctly.

It is only through proper modelling of each design and the detailed study of Building Physics that it is possible to achieve a specification that ensures a comfortable and healthy home all year round. Back