Planning a flooring upgrade for your Sydney home? You’ve picked out the perfect hybrid timber, elegant tiles, or plush carpet. But pull back the old flooring, and you’re often met with a harsh reality: an uneven, bumpy, or sloped subfloor. Trying to lay new flooring over that is a recipe for disaster—gaps, creaks, and a finish that just looks... wrong.So, what’s the secret to that perfectly flat, professional finish? For many Sydney DIYers, the answer is a quality self-levelling compound. But with so many options at the local hardware store, which one is right for you? Let's dive in.What Even Is a Self-Levelling Compound?Think of it as a clever, runny cement-based mix. You add water, mix it to a pancake-batter consistency, and pour it over your prepared subfloor. Gravity and its special formulation do most of the work, 'self-levelling' to fill in dips, smooth imperfections, and create a flat, strong, and stable base for your new floor. It’s the crucial step between "old floor" and "flawless new floor".The DIYer’s Checklist: What to Look for in SydneyNot all levellers are created equal, especially for a DIY project where time and ease of use are critical. Here’s what to check on the bag:Ease of MixingYou're not a professional concreter, right? Look for a compound that mixes easily with a drill and paddle attachment. The best DIY-friendly options have clear water-to-bag ratios and are formulated to be lump-free.Flow & Working Time (Pot Life)This is how long you have to mix, pour, and spread the compound before it starts to set. For a DIYer, a working time of around 20-30 minutes is ideal. It gives you enough time to work without rushing but sets fast enough to move the project along.Drying TimeCheck for two times: "walkable time" (usually 2-4 hours) and "curing time" (when you can lay flooring, often 24 hours). In Sydney's often-humid climate, a faster-drying compound can be a huge advantage, letting you get on with the job.Substrate CompatibilityWhat's your subfloor? Most Sydney homes will have either a concrete slab or timber (like particleboard or plywood in older homes or upper storeys). Ensure the compound is suitable. Many require a specific primer, especially for non-porous surfaces like old tile or timber.Popular Choices for Sydney DIYersWhile we won't endorse a single brand, you’ll find excellent, reliable options at major NSW hardware stores (like Bunnings) from brands like Lanko, Dingo, and Bastion. The key is to look for:Fast-Setting Levellers: Perfect for weekend projects, allowing you to walk on them in a few hours.Flexible/Timber Levellers: If you're working on a timber subfloor, you NEED a flexible compound (often fibre-reinforced) that can handle the slight movement of the wood. Do not use a standard concrete leveller on timber.All-Purpose Levellers: Good for standard concrete slabs with minor imperfections (e.g., up to 10mm).Your Quick DIY Levelling Guide: Don't Skip a Step!Ready to tackle it? A flawless finish comes from flawless preparation.Prep is Everything: Your subfloor must be spotless. Scrape off any old glue, remove nails, sweep, and then vacuum thoroughly. Any dust or debris will ruin the bond.Prime Time: This is the step 90% of DIYers get wrong. Priming seals the subfloor, prevents water from being sucked out of the mix too fast, and ensures a powerful bond. Use the primer recommended by the compound manufacturer.Mix Master: Follow the bag's instructions exactly. Use a clean bucket, add the measured water first, then slowly add the powder while mixing with a drill paddle. Aim for a smooth, lump-free consistency.Pour & Spread: Work quickly! Pour the mix onto the floor in ribbons, starting from the furthest corner and working towards your exit. Use a flat trowel to gently guide it into corners.Roll it Out: While it's still wet, use a spiked roller. This simple tool pops any air bubbles trapped in the mix, ensuring a stronger, smoother final surface.Common DIY Levelling Mistakes in NSW HomesSkipping the Primer: Leads to a weak, dusty, or cracked finish. Don't do it.Over-watering the Mix: It's tempting to add "just a bit more" water to make it flow. This destroys the compound's strength, causing it to crack and fail. Stick to the ratio.Ignoring the Pot Life: Trying to "refresh" a mix that's already started to set will only create lumps. Mix only what you can pour and spread within its working time.Poor Subfloor Cleaning: Pouring over a dusty floor is like painting over grease. It just won't stick.That Floor is Really Uneven... When to Call the Pros?A self-levelling compound is fantastic for imperfections up to about 10-15mm. But what if your floor has serious slopes, major humps, or you're in a heritage Sydney property with challenging foundations? A DIY attempt could make things worse (and very expensive to fix).If you're feeling out of your depth, or you simply want a guaranteed perfect result, it’s time to call in the experts. At Elyment Group (@ElymentGroup), we specialise in professional floor preparation across Sydney. We have the industrial-grade equipment and expertise to handle any subfloor challenge, ensuring your new flooring has the perfect foundation it deserves.Key TakeawaysA level subfloor is non-negotiable for a professional flooring finish.The best DIY compound is one that matches your subfloor (concrete vs. timber) and has a good working time (20+ mins).Do not skip the primer! It's the most critical step for success.For major level issues or a stress-free, guaranteed finish, professional help is your best bet.Ready to get that floor sorted? Whether you tackle it yourself or decide to leave it to the pros, a flat floor is the first step to your dream room. For more expert tips, visit us at elyment.com.au.