What's Trapped in Your Walls: The Building Wrap Revolution with John Martin of Volcano Construction Products

Most Australian homeowners have never heard of a building wrap — and that gap in knowledge, says today's guest, is quietly costing them money, comfort, and their health.John Martin is a chemical material scientist who spent years working internationally, designing high-performance building membranes that are standard practice across European construction. When he returned to Australia and bought a property, he pulled apart his walls and found what he describes as an industry-wide problem: homes built without the products needed to manage air leakage, moisture and transport of water vapour inside wall cavities.In this episode, John breaks down exactly what's happening inside a typical Australian wall — from the older homes with nothing but a weatherboard and timber, through to the foil sarking of mid-century builds, and into the modern era where a high-performance vapour permeable membrane should now be standard. He explains the difference between bulk water and vapour, why your external cladding is not your waterproofing, and how the right membrane acts like a high-performance jacket: keeping air in, keeping weather out, and letting vapour escape before it becomes mould.We talk about how insulation that gets wet simply stops working, why Australia's extreme heat cycles are harder on building materials than European cold climates, and what the 2022 National Construction Code changes mean for anyone building or renovating today.John also shares how he's working with volume builders to lift the baseline standard of Australian homes — not at luxury price points, but as a practical contribution to the millions of mums and dads buying new builds every year.Whether you're planning a build, mid-renovation, or just curious about what's inside the walls you live in every day, this episode will change how you think about your home.For information visit Volcano Construction Products: https://www.vcp.com.au/I'm a Principal Planner and Accredited Energy Assessor. If you’d like to work with me directly in pre-design for your project in Greater Sydney and Surrounds, or use energy rating information to help make project decisions,head to www.sustainableholmes.com.au or message me on www.instagram.com/sustainable_holmes/I’d love to help bring your sustainable home vision to life!