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Condensation – A Comprehensive Overview

National Construction Code Volume 1, Sub Section, Damp and Weatherproofing Part F1.6 references the Australian Standard AS4200.2:2017 Pliable Building Membranes and Underlay.

Brick Veneer Construction and timber cladding without ‘Sarking’ or a breathable membrane contribute after several years to the moisture in the cavities being transferred to the insulation and plasterboard causing mould eventually.

The NCC volume 2 does not reference it but under the Damp and Weatherproofing section it is still a ‘Deemed to Satisfy provision and Performance Requirement by way of the written content. Whilst the Australian Standard AS4200 is the minimum requirement it does not make it mandatory without being referenced in the NCC volume 2.

This is a major floor in the difference between Class 1 and 10 buildings which are residential NCC vol 2 and Class 2-9 which are commercial NCC vol 1.
Why are the general public not protected against damp and mould issues by mandatory regulations.

A lot of project home builders and various other builders fail to recognise this ‘Deemed to Satisfy Provision’ and ‘Performance Requirement’ which is mandatory since it is referenced in a Government Document by the ABCB.

Condensation is not usually a cause for major concern provided that adequate ventilation systems are in place. However, it often goes unnoticed within the building fabric which can eventually lead to a loss of structural integrity due to decay of timber. It can also spur on mould growth and contribute towards pooling of water around your home or business, presenting a safety hazard for all. In this blog post, Sydney Building Defects Inspections and Reports will be looking at the issue of condensation so that you can better understand the reasons for its occurrence, as well as the impact it can have on your building.

If you’re experiencing an issue with condensation, give us a call on 0419 416 040 and we’ll carry out a detailed inspection and report to solve your problem once and for all.

What is condensation?

Condensation is an accumulation of moisture that is most commonly seen in warm environments. Warm air is much more capable of holding moisture than cool air, and therefore you notice cool surfaces such as bathroom windows and mirrors being affected by condensation when you take a hot shower.

You may be surprised to learn that air at 25 degrees C holds around 20 grams of water per kilogram of air. As the air cools, it will start to release the water content as liquid droplets or condensation depending on whether it was cooled as a mass or by a cool surface at or below the dew point, such as those mentioned above.

Where can condensation occur?

Everybody has seen condensation on windows and mirrors before. Daily human activities such as breathing, cooking and hot showers all contribute to higher levels of indoor moisture, as well as the many appliances we use such as gas stoves, heaters and clothes driers. Normally this dissipates with the help of a ceiling extractor fan or increased natural air flow (i.e. by opening the windows).

Interstitial condensation is a much bigger concern, as it occurs within the layers of a building and can easily go unnoticed. The inside of a building is much warmer than the exterior, and the diffusion of air causes the dew point to be reached within the building fabric.

Moisture levels are often higher within buildings than they are outdoors. Many factors contribute to this, but it is principally caused by moisture in the ground. The ground is naturally damp, and moisture levels can fluctuate due to leaks as well as run-off from watering. Concrete slabs can minimise the ingress of moisture, but buildings that have suspended timber floors will often experience high levels of indoor humidity caused by the moist subfloor space.

Rising damp is a particularly common issue in older buildings, as they often lacked adequate damp courses in the masonry walls. This allows moisture to seep inside, contributing to the development of rising damp as well as creating a source of moisture that could contribute to condensation issues in other parts of your building.

Left untreated, moisture will begin to affect timber frame construction as well as cause damage to your ceilings, wall linings and paintwork.

Methods of controlling moisture in buildings

You need to be aware of vapour levels within your building. Issues are caused by:

  • Moisture levels becoming too high
  • Low temperatures within the building fabric
  • Water vapour unable to be controlled and is dispersed into an area with cold temperature

There are many ways to go about controlling moisture and preventing interstitial condensation, but the most effective method is the use of an appropriate vapour barrier at the time of construction. Vapour barriers are usually made from reflective aluminium foil or polyethylene sheet, and they are remarkably effective at preventing the diffusion of moisture through walls, ceilings, floors and roof assemblies. Vapour barriers should be installed beneath concrete slabs and sheet metal roofs. Some buildings may require some vapour permeance, and in these cases it is recommended that small holes are created within the membrane.

During the design phase, care should also be taken to provide adequate thermal insulation. This will help to ensure that surface temperatures remain high, thus preventing condensation. Double glazing for window glass is also gaining traction as a popular way to prevent condensation, although it does cost significantly more.

Extraction fans should be installed in every bathroom, kitchen and laundry. This will go a long way in helping to keep humidity levels low and ensuring that moisture is expelled outdoors without entering your building foundations.

Solve your condensation issues – Contact SBDIR Today

You could have a condensation issue without even realising it. Some of the most common places which experience condensation include metal roofs, vented ceilings, tiled roofs, flat roofs and beneath the floor. Peace of mind is priceless, and SBDIR can provide you with a comprehensive report that will put your mind at ease.

We would strongly recommend carrying out an inspection if you have an enclosed sub-floor space with damp ground, or if you live in an area which experiences winter temperatures of approximately 4°C or lower in winter. These conditions are highly conducive to timber rot, and if caught early you may be able to take remedial action to prevent extensive damage to your home or business.

Give us a call on 0419 416 040 today, or submit an enquiry through our website.