When it comes to building or renovating, the subfloor is one of those hidden elements most homeowners don’t think about — yet it can have a big impact on your home’s indoor air quality, durability, and environmental footprint.
Let’s look at the different options, their pros and cons, and what you need to know to make an informed choice.
Recycled Timber: The Healthier, Greener Choice
- Why it’s great: Recycled timber is one of the best options for both the environment and your health. Reusing timber means less waste and fewer new resources consumed. It also avoids many of the chemical adhesives found in engineered products.
- What to watch for: Recycled materials often need more prep time. You may need to remove nails, check for mould, and ensure the moisture content is suitable before installation. Moisture control is critical to reducing mould risk.
Engineered Wood Products (Plywood, MDF & Particleboard)
Engineered wood is widely used because it’s affordable and readily available. But it comes with some important considerations.
- Chemical Resins: Most engineered products are bonded with formaldehyde resins (urea formaldehyde or phenol formaldehyde). Formaldehyde is a Group 1 carcinogen — exposure has been linked to irritation of the eyes, nose, and lungs, as well as headaches, dizziness, disturbed sleep, and longer-term health effects.
- Mould Susceptibility: Because these products are heavily processed and glue-bonded, they retain moisture longer if they get wet, making them more prone to mould growth.
Plywood vs MDF: Which is Safer?
- Plywood: Typically made with phenol formaldehyde, which off-gases far less than urea formaldehyde (around 90% less). Off-gassing is the slow release of chemicals as gases from building materials into the air you breathe — meaning fewer harmful emissions circulating indoors. Plywood also absorbs less water than MDF and resists mould for longer, making it a safer and more durable choice in many situations.
- MDF/Particleboard: Usually made with urea formaldehyde, which off-gases at far higher levels and provides an easier food source for mould.
Pro tip: If you use plywood, let it off-gas in a dry, ventilated space (like a garage) before installing. Emissions are highest in the first few weeks but reduce significantly over time.
How to Minimise Risks if You Choose Engineered Products
If budget or supply constraints mean you need to use engineered wood, here are ways to reduce health and environmental impacts:
- Choose phenol formaldehyde–based plywood over MDF/particleboard.
- Allow time for the material to off-gas before installation.
- Use screws or nails instead of glue to reduce VOC emissions.
- Always install a moisture barrier beneath flooring to prevent damp issues.
- For new homes, an elevated foundation can reduce rising damp risks.
Subfloor Options Ranked (Health & Environment)
- Recycled Timber — Best for air quality and sustainability.
- Plywood (phenol formaldehyde) — Middle ground: lower emissions, better durability.
- MDF / Particleboard (urea formaldehyde) — Highest emissions and mould risk.
Your subfloor might be out of sight, but it shouldn’t be out of mind. By understanding the health risks, environmental impact, and durability of different materials, you can make smarter choices that support both your home’s longevity and your family’s wellbeing.
If you’re planning a custom build or renovation, don’t leave material choices to chance. At Locspec, we guide our clients through every detail — from hidden subfloors to high-performance finishes — so you can build a healthier, longer-lasting home.
👉 Fill out the enquiry form to get clarity on the right material choices for your project.