Understanding Off-Gassing in Home Construction

When building a new home, most people focus on looks, function and cost. Often overlooked is what the materials and products inside it do to your indoor air quality and health.

The big one is off-gassing, where volatile organic compounds (VOCs) are released into the air from materials and products. This post covers where it comes from, the health effects, and how to minimise it in your new home.

What is Off-Gassing?

Off-gassing is the release of chemicals, particularly VOCs, from materials and products in your home. VOCs evaporate into the air at room temperature and are a major contributor to indoor air pollution. They come from paints and varnishes, adhesives, flooring, cabinetry and furniture, and emissions can continue long after installation.

Common Sources of Off-Gassing

Building materials: Plywood, particleboard and medium-density fibreboard (MDF), used for cabinetry, joinery and mouldings, can contain urea-formaldehyde resins that off-gas formaldehyde, a known carcinogen. Ask for E0 or E1 rated board under the Australian formaldehyde emission standards (E0 is the lowest-emitting). Exterior-grade plywood uses phenol-formaldehyde resin, which emits less.
Paints and finishes: Conventional paints, varnishes and stains can off-gas for weeks or months after application. Low-VOC and zero-VOC paints perform similarly with far fewer emissions, and water-based varnishes and stains generally contain fewer VOCs than oil-based ones.
Flooring: Carpets can release VOCs from the fibres, backing and adhesives. Vinyl flooring (including LVT) can off-gas phthalates and VOCs, and traditional polyurethane timber finishes release VOCs too. Look for GECA-certified carpets, and consider water-based or natural oil timber finishes.
Furniture and upholstery: Pressed-wood furniture can be a significant source of formaldehyde. Solid timber furniture usually emits far less formaldehyde than pressed-wood furniture. Foam cushions and mattresses can release VOCs from flame retardants and other chemicals.
Household products: Many cleaning products and air fresheners release VOCs. Choose low-toxicity cleaners, and skip the air fresheners.

Health Effects of Off-Gassing

Exposure to VOCs can have both short-term and long-term health effects. Short-term exposure may cause headaches, dizziness, nausea, and irritation of the eyes, nose, and throat. These symptoms can be particularly pronounced in sensitive individuals, such as those with allergies or respiratory conditions.

Long-term exposure, especially to higher concentrations, can lead to more serious problems, including respiratory issues, liver and kidney damage and even cancer.

Minimising Off-Gassing in Your Home

Reducing off-gassing comes down to choosing the right materials, ventilating well and keeping on top of maintenance:

Choose low-VOC products: For paints, finishes, adhesives and building materials, look for low-VOC or zero-VOC labels and GECA certification, and specify low-VOC paints in your colour selections and E0 or E1 board for cabinetry.
Ventilation: Ventilate well during and after construction. Use exhaust fans, open windows, and consider a whole-house ventilation system. In the weeks after handover, open the house up daily and run the exhaust fans to flush out VOCs from new paint, cabinetry and flooring before you move in, if you can.
Air purification: Choose a purifier with an activated carbon filter for VOCs. A HEPA filter alone catches particles, not gases. Purifiers help most in bedrooms and living areas, where you spend the most time.
Let materials air out first: If possible, let new furniture and rugs off-gas in a well-ventilated area (like the garage with the door open) before bringing them inside.
Seal or Coat Pressed Wood Products: If you have to use products made from pressed wood, choose those that are laminated or have a sealed surface to reduce emissions. Applying a sealant to exposed surfaces can also help reduce VOC emissions.
Regular cleaning: Clean regularly to reduce dust, which can carry chemicals, and use low-toxicity cleaning products.
Monitor indoor air quality: An indoor air quality monitor that reads VOCs gives you real-time data, so you can ventilate when levels rise.

Advanced Strategies for Minimising Off-Gassing

If you want to go further:

Healthy home design: Work with architects and builders experienced in healthy homes: low-emission materials, good ventilation, and passive design.
Smart ventilation: Systems that adjust ventilation automatically based on real-time air quality data.
Biophilic design: Natural materials, plenty of natural light and indoor plants to connect you with nature and improve how the home feels.

Conclusion

Off-gassing matters most in a brand-new home. Choose low-emission materials, ventilate hard in the first weeks, and you'll significantly cut your exposure to VOCs.