Self-levelling compound is a game-changer for creating smooth, even floors before installing tiles, vinyl, or other coverings. Whether you're a homeowner tackling a renovation or a professional preparing a subfloor, understanding how thick you can pour self-levelling compound—and its limitations—is crucial for a flawless finish. This guide breaks down everything you need to know, from standard thicknesses to practical tips, ensuring your flooring project is a success. Follow us on X @ElymentGroup (https://x.com/ElymentGroup) or visit elyment.com.au (https://elyment.com.au) for more expert insights! What Is Self-Levelling Compound? Self-levelling compound is a polymer-modified, cement-based mixture designed to create a flat, smooth surface on uneven subfloors. It’s poured as a liquid and spreads naturally to fill low spots, eliminating bumps and dips. Ideal for concrete, timber, or tiled subfloors, it’s a go-to solution for preparing floors for coverings like laminate, vinyl, or carpet. But how thick can you pour it? The answer depends on the product, subfloor type, and application method. Let’s dive into the details. Standard Thickness for Self-Levelling Compound Most self-levelling compounds have a recommended thickness range, typically between 3mm and 50mm in a single pour, though some specialised products allow for thinner or thicker applications. Here’s a breakdown: Minimum Thickness: Most compounds require at least 3mm to ensure structural integrity and prevent cracking. Some feather-finish products, like Ardex Feather Finish, can be applied as thin as 0.1mm for minor surface smoothing. Maximum Thickness: Standard compounds are safe up to 20-50mm in one pour. High-performance options, such as BAL Level Max, can reach 80mm, while niche products like Uzin NC 170 allow even thicker applications in specific cases. Special Cases: For depths beyond 50mm, multiple pours or alternative solutions like screeds may be needed to maintain stability. Always check the manufacturer’s guidelines, as exceeding the recommended thickness can lead to cracking, poor curing, or an uneven surface. Factors Affecting Pour Thickness Several factors influence how thick you can pour self-levelling compound: Product Type: Different compounds have unique formulations. For example, fibre-reinforced compounds like Larsen’s SLC 1550 Fibre Flex can handle up to 50mm due to added strength. Subfloor Material: Concrete, timber, or tiles require specific preparation and primers, which can affect the compound’s adhesion and thickness limits. Environmental Conditions: Temperature and humidity impact drying time and curing. Thicker pours in humid conditions may take longer to set, risking surface imperfections. Application Method: Using a gauge rake or trowel ensures even spreading, especially for thicker pours. Spiked rollers help remove air bubbles, maintaining stability. Intended Floor Covering: Heavy-traffic areas or specific coverings (e.g., small-format tiles) may require thicker or reinforced compounds for durability. Can You Pour Self-Levelling Compound Thicker Than Recommended? Pouring beyond the manufacturer’s recommended thickness is risky. Here’s why: Cracking: Thick pours generate more heat during curing, which can cause shrinkage and cracks. Slow-setting compounds with fly ash additives may reduce this risk. Poor Bonding: Without proper priming, thick layers may not adhere well to the subfloor, leading to delamination. Uneven Curing: Thicker applications take longer to dry, increasing the chance of air pockets or an uneven finish. If you need a thicker layer, consider these alternatives: Multiple Pours: Apply the compound in layers (e.g., 20mm at a time), allowing each layer to dry fully (typically 24-48 hours) before adding the next. Screeds or Aggregates: For depths over 50mm, use a traditional screed or mix the compound with aggregates to extend its thickness, as seen in products like CONCRETE LEVELER. Consult a Professional: For complex projects, contact experts like those at Elyment Group (https://elyment.com.au) for tailored advice. Step-by-Step Guide to Pouring Self-Levelling Compound To achieve the perfect pour, follow these steps: Prepare the Subfloor: Clean the surface thoroughly, removing dust, grease, or debris. Fill cracks or holes with a suitable filler. Apply a primer to enhance adhesion, especially for porous surfaces like concrete. Mix the Compound: Use clean, room-temperature water and follow the manufacturer’s mixing ratio. Mix with a drill and paddle attachment for a lump-free consistency, similar to “pea soup.” Work quickly, as most compounds set within 20-30 minutes. Pour and Spread: Start at the furthest corner and work towards the exit. Pour evenly and use a gauge rake or trowel to spread to the desired thickness. Use a spiked roller to remove air bubbles and ensure a smooth finish. Allow to Cure: Thin layers (3-5mm) dry in 2-4 hours, while thicker layers (up to 50mm) may take 24-48 hours. Avoid foot traffic until fully set, and wait 1-2 weeks before installing sensitive coverings like vinyl. Common Mistakes to Avoid Ignoring Manufacturer Guidelines: Always follow the product’s thickness and mixing instructions to avoid failure. Skipping Primer: This can cause poor adhesion or air bubbles, especially on tiles or timber. Pouring Too Thick: Exceeding limits without multiple pours risks cracking or instability. Inadequate Preparation: Dust or grease on the subfloor can compromise the compound’s performance. Rushing the Process: Allow sufficient curing time to prevent damage to the new surface. Key Takeaways Standard Thickness: Most self-levelling compounds can be poured between 3mm and 50mm, with some products allowing up to 80mm or more. Product Matters: Check the manufacturer’s specs, as formulations vary (e.g., fibre-reinforced for thicker pours). Multiple Pours: For depths over 50mm, apply in layers or use screeds for stability. Preparation Is Key: Clean, prime, and mix properly for a smooth, durable finish. Expert Help: For large or complex projects, consult professionals like Elyment Group (https://elyment.com.au). Next Steps for Your Flooring Project Ready to level your floors like a pro? Start by selecting a high-quality self-levelling compound suited to your subfloor and thickness needs. For expert advice or professional services, reach out to the team at Elyment Group. Visit elyment.com.au (https://elyment.com.au) or follow us on X @ElymentGroup (https://x.com/ElymentGroup) for more tips and inspiration. 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