Living in a classic Sydney apartment is a dream for many. Those older blocks in areas like the Eastern Suburbs, North Shore, or Inner West have character, but they can also hide a costly secret right under your feet. We’re talking about magnesite flooring. You’ve likely never heard of it. Yet, this flooring material, common in NSW Autofill blocks built from the 1960s to the 1980s, could be a financial time bomb for you and your strata. So, what is it, and how can you tell if it’s lurking under your carpet or floorboards? This 5-minute guide is here to help. What is Magnesite Flooring (And Why Should You Care)? Think of magnesite as a cheap and quick floor-levelling topcoat that was popular for its time. It was laid over concrete slabs to create a smooth surface before the carpet or lino went down. The problem? Magnesite is like a sponge. It absorbs moisture from the air, from spills, or even from a damp concrete slab. When it gets wet, it releases chlorides, which then seep into the concrete, corrode the steel rebar inside, and cause “concrete cancer” or spalling. The result? Cracked, unstable slabs and repair bills that can easily run into the hundreds of thousands for the building. Is Your Sydney Apartment at Risk? Magnesite is overwhelmingly a Sydney and NSW problem. If your apartment block was built between the 1960s and the late 1980s, your risk level is high. If your building is newer, you’re likely in the clear. The 5-Minute Visual Guide: How to Identify Magnesite You don’t need to be a builder to do a quick check. Grab a torch, and let’s investigate. Step 1: Check Your Building’s Age As mentioned, if your strata block is from the 60s, 70s, or 80s, stay alert. This is the number one indicator. Step 2: Look for Surface Clues (Even Through Carpet) Are there mysterious “bubbles” or lumps under your carpet? Is your lino or vinyl flooring lifting or cracking for no reason? These can be signs the magnesite layer beneath is swelling or breaking down. Step 3: Listen for ‘Drummy’ Sounds Tap your floor with your knuckles or a wooden spoon (gently!). If it sounds solid in some places but hollow or “drummy” in others, it could mean the magnesite has detached from the concrete slab below. Step 4: The ‘Corner Peek’ (The Tell-Tale Sign) This is the most reliable visual test. Find a discreet spot, like the inside of a wardrobe or a corner of a room. Gently pull back the carpet. You may need to use pliers to grip the edge. Shine your torch on the subfloor. What you’re looking for: A layer of material that is not concrete. Magnesite typically looks like a soft, crumbly, or powdery layer, often in a reddish-brown, tan, or greyish colour. It might look a bit like compacted sawdust or clay. If you see this, you’ve almost certainly got magnesite. Found It? Don’t Panic. Here’s What’s Next. Identifying magnesite is the first, crucial step. The good news is that if it’s dry and in good condition, it’s not an immediate emergency. The bad news is that it’s a ticking clock. Your next step is to understand the true condition of the slab. At Elyment Group, we specialise in magnesite testing and remediation across Sydney. We can help you determine the extent of the problem and the most effective way to manage it, protecting your investment. Want to run a quick preliminary check online? Use our AI tool to check for magnesite at 🔗 https://magnesitecheck.com.au/ for a free assessment. Key Takeaways At-Risk Buildings: Sydney/NSW apartments built from the 1960s–1980s. What It Is: A spongy, moisture-absorbing topcoat. The Risk: Causes “concrete cancer” (spalling) by corroding steel rebar. How to Check: Look in a wardrobe corner for a soft, crumbly, reddish-brown or grey layer under the carpet. What to Do: Don’t ignore it. Get a professional assessment. CONFIRM YOUR MAGNESITE RISK NOW /* Wrapper */ .btn-magnesite-cta-wrapper { text-align: center; margin-top: 30px; margin-bottom: 20px; } /* CTA Button */ .btn-magnesite-cta { background: linear-gradient(135deg, #022b5f, #0d1b2a); /* Gradient for depth */ color: #FFFFFF; border: none; padding: 14px 32px; border-radius: 6px; cursor: pointer; text-align: center; display: inline-block; font-family: Arial, sans-serif; font-size: 1.1rem; font-weight: bold; letter-spacing: 1px; text-transform: uppercase; text-decoration: none; transition: background 0.3s ease, box-shadow 0.3s ease, transform 0.2s ease; box-shadow: 0 4px 15px rgba(2, 43, 95, 0.4); position: relative; overflow: hidden; } /* Hover + Focus */ .btn-magnesite-cta:hover, .btn-magnesite-cta:focus-visible { background: linear-gradient(135deg, #16443e, #1b263b); box-shadow: 0 6px 20px rgba(22, 70, 138, 0.7); transform: scale(1.03); outline: none; } /* Active state */ .btn-magnesite-cta:active { transform: scale(1); box-shadow: 0 3px 10px rgba(2, 43, 95, 0.5); } Don’t let a hidden floor problem become a six-figure nightmare.