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Why Should You Be Concerned About Condensation & Moulds

Most people think that the home is the safest place. But your residence or apartment building could also be the safest place for other organisms such as moulds and fungi which can cause strong allergic reactions to the occupants. In fact, right now up to 40% of new residential buildings may have mould issues.

This is what happens if we ignore Condensation. Water vapour contained in the air will start to condense when it reaches the dew point temperature. This is the temperature level when the relative humidity of the air reaches 100%. We don’t even have to wait for that 100%. At 50% relative humidity and persistently high humidity levels, the place will become a thriving environment for moulds and fungi.

How to stop condensation & mould growth

The key then is to stop or limit condensation. This can be accomplished by allowing damp or wetness to dry out faster than it can form (discourage mould growth and reproduction). One way to achieve this is by increasing the levels of water and air tightness. After all, air travels along with water vapour and then condenses on cooler surfaces (if the room or apartment interior is cooler). The air may come into the dwelling through holes, cracks and gaps in the structure.

Roof space (including roof and ceiling cavities) can also be vulnerable to condensation. One solution to this is to facilitate or improve ventilation in the cavity through a whirlybird. This will then discourage significant condensation to accumulate. Aside from facilitating ventilation and air circulation, a whirlybird can also suck out the heat and moisture from the roof or ceiling cavity (e.g. prevents heat build-up in the cavity during winter). Often it’s recommended to install two soffit vents per whirlybird to allow for excellent air circulation into and out of the cavity.

Prevent water penetration & other advantages

Aside from preventing or limiting condensation, another way to prevent mould proliferation is by preventing water penetration into the building. Builders and renovators accomplish this by installing roof sarking, which is fitted during roof installation. Sarking provides protection against the driving rain and create additional thermal insulation as well (e.g. added benefit of better building energy performance). Moreover, the installation of sarking can collect condensate dripping from the non-absorbent underside of roof sheeting and drain it to the guttering. As a result, this helps in stopping condensate from forming and accumulating and mould growth as well.

Aside from roof spaces, other areas of a residential building such as bathrooms (specifically the stud walls) are also vulnerable to condensation. For instance, during a hot shower the amount of water vapour rises (higher humidity levels). The water vapour might get trapped into the bathroom walls and condense later, which then in turns encourage mould growth. To limit or minimise this, builders and renovators might improve area ventilation, insulate interior walls and install vapour barriers (to slow down or halt moisture movement through the material).

Why should you be concerned about condensation & moulds

More and more people now are getting concerned about condensation and mould growth in their dwellings. Moulds are insidious and right now they might be already affecting your health and/or that of your tenants.

It’s especially the case in new residential buildings because some contractors might have cut corners to save time and money. Moreover, lack of understanding about condensation and mould growth are making the problems worse. As a result, many occupants (whether they’re aware or not) are already suffering from the toxins and irritants being released by moulds. In addition, building owners and managers have to deal with the expensive consequences later about the future correction of poor construction practices.

Thankfully, clear technical standards are now being formulated (e.g. National Construction Code 2019). More emphasis might now be placed on condensation and water vapour management. There could then be new performance requirements on indoor humidity conditions, rain absorption, heating and cooling set points, roof space ventilation, water control membrane and other important factors that relate to condensation levels in residential buildings.

It’s an amazing initial step to improving occupant health. But it’s still an incomplete and evolving measure to minimise mould growth and guarantee the safety of occupants. For instance, condensation is the result of several complex interactions between the building and the environment. Occupant activities make the interactions even more complex because of the release of water vapour through cooking, washing and showering. We also have to consider the changing climate and weather patterns. The resulting unpredictability may create never before seen combinations of temperature, humidity and precipitation levels. This may then require an update in current standards to better address the changes.

Nevertheless, it’s up to the owner or manager of the property to minimise the risks to the occupants. It’s always recommended to detect the main condensation points and correct them as early as possible. And if you suspect other construction defects in your home or apartment building, now’s the time to take the initial step.

Here at Sydney Building Defects Inspections and Reports (SBDIR), we can perform a rigorous inspection of your property for poor workmanship and construction defects. We always use specialist tools and stay updated with the latest building and construction codes in Australia (including Building Code of Australia and National Construction Code). Send us an online enquiry if you suspect something is defective in your building.