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Why are we doing this?

Traditionally, Australian & NZ buildings were not airtight and had little or no insulation.

However, as a result of new developments and the introduction of mandatory energy efficiency requirements, building practices are having to adapt, requiring a change in detailing so that moisture related problems are adequately managed.


JPA Designer software

Calculating the risk of condensation

The Australian Building Codes Board [ABCB] Handbook “Condensation in Buildings” highlights the damage condensation can cause to the fabric of buildings and to the health of their occupants: it recommends that designers assess the risk of interstitial condensation during the design stages of any project and modify their design proposals if condensation is predicted.

To facilitate that, JPA TL Ltd has launched a new version of its well-proven JPA Designer thermal analysis program, modified specifically for climate conditions in Australia and New Zealand. In addition to calculating R values for heat flow in both directions through roofs, walls and floors the program will assess the risk of interstitial condensation in accordance with ISO 13788:2012 and will highlight the risk of condensation within a multi-layer construction.

Users can build a layer-by-layer model of any construction using the built-in database of material and products and then set the climate conditions from a comprehensive dataset of locations, which includes the 69 climate zones defined in NatHERS. The program will then show where condensation is predicted within the construction, the amount of condensate deposited or evaporated each month, the maximum amount deposited and the annual moisture balance.

You can download a free demonstration version of the program by clicking on the 'Download' button above. Please note: the demonstration version does not provide any R-Value answers. To obtain a free, time-limited keycode which will unlock the answers and allow further evaluation, just email your details to

To purchase a licence, go to the Purchasing page or contact us at