Our built environments, like our natural environments and our bodies, need to maintained and transformed so they are winter ready. Just as we rug up and put on a coat in order to keep warm, so too must our buildings be prepared for the changes in weather conditions.
One of the key issues in housing developments in the wintertime is – unsurprisingly – the cold, rainy weather.
This problems these conditions cause are, however, not what one might typically assume.
With the longer stretches of rain, the water can erode rooftops, causing wood rot and other issues. It is not initial leaking that concerns to developers, however, so much as ‘ghost leaks’ – leaking that occurs days later.
These issues are caused when the differentiation between inside and outside temperatures are so great that condensation forms on the inside of a building.
Not only can this condensation breed harmful bacteria, cause corrosion, timber decay and sick building syndrome, it is on the increase.
As the passive model of housing becomes more popular, more developers are choosing to design interior spaces that can control the climate passively. While this is great for both the environment and for energy bill savings, the possible lack of ventilation and the increased gaps between inside and outside further increase condensation issues.
According to the Commonwealth Scientific and Industrial Research Organisation (CSIRO), this issue is high on the agenda of industries worldwide.
foil vapour barrier
“Higher levels of insulation may introduce unforeseen problems where they are incorporated into construction styles which have previously been relatively immune to condensation,” the organisation says. “This is because insulation, whilst it keeps some surfaces warm, also keeps other surfaces cold.”
This kind of environment breeds bacteria that causes interior air quality to decrease and can bring about sick building syndrome, which can cause general health problems, itching, nose and eye irritation among other health issues, and exacerbate asthma.
In order to avoid these issues, a number of measures can be taken. First and foremost, developers need to make sure that all materials used both inside and outside need to be completely dry throughout construction, or be in a position where they will become completely dry.
Second, building ‘wrapping’ can be used to prevent moisture intrusion. This includes wrapping a vapour prevention material around the structure that prevents long-term moisture. Examples of the materials used for this include foil sarking, perforated foil sarking or reflective bubble foil type sarking installed behind the external wall claddings or brick veneer, or under roof tiles.
Finally, it is imperative that highly-insulated or airtight buildings have sufficient air exchange systems such as HVAC to allow for even the tightest buildings to ‘breathe’.
Buildings need to be winter tight in a way that doesn’t choke them or allow them to sweat. Even though the initial reaction in winter is to rug up and keep the cold out as much as possible, this needs to be done in a considered way or it is simply going to cause greater problems in the long run.
