Reducing vapour intrusion into your home

If your home is potentially affected by vapour intrusion, there are some simple and practical precautions you can take to dilute or disperse vapour (by increasing the flow of fresh air from outside to inside or below a house) and prevent vapour from rising from below the ground into the house.

Open windows and doors

Promote natural breezes by opening windowsOpening external windows, doors and vents can increase the air flow inside the house and reduce the potential build-up of vapours. Keeping windows slightly open when possible may also be effective.

Reducing the time that a house is fully closed can prevent vapour build-up, as can ‘airing it out’ when you come home after it has been fully closed.

If vapour intrusion is likely to be an issue, the most important rooms to consider ventilating are those that people spend the most time in, such as bedrooms and living rooms. You can promote the movement of fresh air by opening windows or doors at opposite ends of the house to allow the natural airflow to replace indoor air with fresh air from outside.

Under-floor ventilation

If your home has a crawlspace (the area between the floorboards and the ground), increasing ventilation through this space can reduce the amount of vapour that enters the indoor air in your house. This can be done by clearing vegetation and blockages away from ventilation points outside your home.

Ensure vents are clear to allow maximum airflow

Replace older vents with newer vents

Older style vents (often made of clay) have smaller holes and tend to not ventilate as effectively as modern steel or plastic vents. Replacing older vents with newer vents may improve ventilation within the crawlspace. Installing additional vents in the crawlspace to increase airflow beneath a home may also reduce the concentrations of vapour accumulating inside the home.

Ensure vent arrangement is effective for the prevailing wind conditions

Keeping your floor in good condition

If you have timber floorboards, you can seal the gaps with a high-quality flexible (silicon) sealant available from hardware stores to ensure there are no holes or spaces for vapours to enter from below. This can also be effective for managing the energy efficiency of your home.

If your home is on a concrete slab, inspect underneath the carpet and ensure any cracks are sealed, if feasible. If it is not possible to access areas of your floor where cracks or gaps may exist, another solution might be to reconsider how different areas of the house are used. For example, rearranging rooms where the most time is spent will minimise the use of space where ventilation may be lowest, or where the flooring gaps allow air to be drawn in from below.

You should also consider sealing the gaps where pipes enter your home, such as in the bathroom, laundry and kitchen.

Tips for the safe use of exhaust fans

Some household appliances, such as kitchen exhaust fans, rangehoods and bathroom fans, can create a suction effect by extracting air upwards and inadvertently drawing vapours in from below the house. If you have any of these appliances installed in your home, it is recommended that external windows and doors are kept open while you have them turned on. By keeping windows or doors open, air is mostly drawn in from the outside rather than from beneath the house.