Building trick to manage condensation
If you have been keeping up with the pace of building & construction trends, you will know that new construction of dwellings and apartments is about to move to a 7-Star Energy Rating. Whilst this benefits the world in which we live in, the downside is that buildings are being ‘sealed up’ like a surfer’s winter wetsuit, thus becoming less vapour-permeable or breathable. The impact on buildings is increased condensation.
Condensation occurs where the moisture in the air meets a cooler surface (for example, when water droplets form on the outside of your cold drink). This is because when air hits a surface cooler than itself, the maximum amount of water vapour it can hold will decrease, and some of its water vapour may condense out into liquid water. The temperature at which this happens is called the dew point.
Condensation in your home may occur on surfaces or inside construction systems like walls, ceilings or floors (called interstitial condensation). Interstitial condensation can lead to mould, mildew and decay. This can cause rotting of building materials and, if mould spores become airborne indoors, harmful effects on human health.
The act of breathing releases water vapour, so you add moisture to the inside of your home as you breathe. Household activities such as showering, cooking, washing and drying clothes also contribute to a high level of water vapour inside the home. The risk of condensation forming increases if cold surfaces are present (for example, single glazing or standard aluminium-framed windows and uninsulated walls). Condensation is especially prevalent during winter when inside temperatures are warm and outside temperatures cold.
The National Construction Code requires that all new buildings are designed to manage condensation risk. Performance Requirement FP6.1 of NCC 2019 Condensation and Water Vapour Management states, “In a sole-occupancy unit of a Class 2 Building or a Class 4 part of a building, risks associated with water vapour and condensation must be managed to minimise their impact on the health of occupants.”
Careful attention to correct specification and installation of building materials is important to avoid condensation in your home. This includes components such as glazing, insulation, mechanical ventilation, and sarking but my tip is to also make sure the HVAC system that you install in the building has a DRY MODE.
Dry Mode dehumidifies the air in your building. It is a smart way to soak up all the excess moisture or humidity in the air – on a large-scale basis. The fan inside of your air conditioner will still run, it just won’t be blowing any cool air. That way, the air passes through the system so that the vapor can condense in the evaporator, recirculating the dry air back into the room.