You’ve invested in a self-levelling compound, expecting a perfectly flat, pristine surface for your new flooring. Yet, here you are, staring at frustrating lumps and high spots. It’s a common problem for many Sydney homeowners, but don't worry—it’s entirely fixable. Achieving that billiard-table flatness is crucial for the longevity and look of your final floor, whether it's tile, timber, or vinyl. This guide will walk you through the professional approach to grinding down those high spots, ensuring your NSW property has the flawless foundation it deserves. Why Do Self-Levelled Floors Have High Spots? It’s a fair question. Isn't "self-levelling" meant to do just that? While the compound is designed to flow and find its own level, several factors, especially in NSW's varied climate, can interfere: Incorrect Mixing: The compound-to-water ratio is a precise science. Too thick, and it won't flow properly, causing ridges. Rapid Drying: A sudden hot day in Sydney or too much airflow can cause the surface to "skin over" before it has fully settled. Subfloor Issues: The compound might settle perfectly, but if the underlying subfloor has dramatic dips, the leveller can pool, creating raised edges. Application Technique: Inexperienced application, like over-trowelling, can disturb the settling process and create imperfections. The Risks of Ignoring Uneven Floors in Your Sydney Home Tempted to just lay the new floorboards over it? We'd advise against it. Ignoring high spots can lead to: Wasted Materials: Floating floors will have a "bouncy" feel and fail prematurely. Tiles will crack under pressure, and adhesives won't bond correctly. Poor Aesthetics: Imperfections will "telegraph" through vinyl and hybrid flooring, showing every lump and bump. Safety Hazards: Uneven surfaces can be tripping hazards, especially in high-traffic areas. Tools & Safety: What You Need Before You Start Grinding Grinding concrete or levelling compound creates fine, hazardous dust. Safety is non-negotiable. Essential Safety Gear: P2/N95 Respirator Mask: To protect from silica dust. Safety Goggles: Full-seal goggles are best. Hearing Protection: Grinders are extremely loud. Gloves: For grip and to protect from vibration. Grinding Equipment: Concrete Grinder: For larger areas, a walk-behind grinder is ideal. For small spots, a 5-7 inch (125mm-180mm) angle grinder with a diamond cup wheel will work. Dust Shroud: A non-negotiable attachment for your grinder. HEPA Filter Vacuum: Connects to the dust shroud to capture dust at the source. Straight Edge or Level: A long (2-3 metre) spirit level to identify the exact high spots. A Step-by-Step Guide to Grinding High Spots With your safety gear on, you're ready to tackle those bumps. Step 1: Identify and Mark the High Spots Take your straight edge or level and sweep it across the floor. Everywhere it pivots or "seesaws," you have a high spot. Mark the entire perimeter of these areas with a pencil or chalk. Step 2: Set Up Your Dust Extraction Attach the dust shroud to your angle grinder and connect the hose from your HEPA vacuum. Turn the vacuum on before you start the grinder. This step is critical for managing dust in your home. Step 3: Begin Grinding Start the grinder off the floor and gently lower it onto the marked high spot. Move the grinder in a consistent, sweeping motion (like a fan). Don't press down hard; let the weight of the tool and the diamond cup wheel do the work. Keep the grinder flat to avoid creating new divots or swirls. Step 4: Check Your Work Frequently Stop every 30-60 seconds. Vacuum the area clean and slide your straight edge over it again. You are aiming to "shave" the high spot down, not eliminate it in one pass. Patience is key. Step 5: Feather the Edges Once the main high spot is level, you'll need to "feather" the edges. This means lightly grinding the area just outside your original mark to create a smooth, gradual transition to the rest of the floor. This prevents a visible "dish" effect. Step 6: Final Clean-Up Once all spots are level, give the entire floor a thorough vacuum with your HEPA filter vacuum to remove any residual dust before proceeding with your flooring installation. When to DIY vs. When to Call the Pros in NSW So, is this a DIY job? For a few small, minor spots, an experienced DIYer can often manage. However, you should call a professional service like Elyment Group if: The high spots cover more than 10-15% of the floor. The high spots are more than 5mm tall. You don't have the specialist dust extraction equipment. You're located in a multi-story Sydney apartment, where dust and noise control are critical. Professionals use large-scale planetary grinders that get the job done faster, cleaner, and with a much flatter result. For expert floor preparation across NSW, it's always best to get a professional opinion. You can find us on X as @ElymentGroup. Key Takeaways Don't ignore them: High spots will ruin your final flooring. Safety first: Silica dust is hazardous. Use a mask, shroud, and HEPA vacuum. Mark your spots: Use a long straight edge to find the exact problem areas. Go slow: Grind in sweeping motions and check your progress often. Know when to call: For large or significant issues, professional grinding is the best investment. 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