Key takeaways
- A self-levelling compound is a short and easy method of preparing uneven floors (applicable to concrete, tiles, and more).
- Surface preparation and priming are important for ideal adhesion and a smooth finish.
- Mixing the compound to the correct consistency and applying it evenly when applying it will yield the best results.
- Drying time depends on thickness, humidity and temperature, and full curing takes 48 hours.
- Using the proper techniques and timing, you can avoid common problems like spreading unevenly or drying too soon.
- Next Level provides professional screeding services using self-levelling compound.
When exploring top coat options, self-levelling compounds have changed the game in terms of floor preparation, proving to be a more modern and time-saving alternative to conventional screeds. Well known for their versatility, these compounds can be applied to a variety of surfaces such as concrete and tiles, providing a perfectly level substrate to lay tiles, carpeting or other finishes on.
In this guide, we will be covering all there is to know about self-levelling compounds, including preparation, application methods, and tips for troubleshooting common concerns so that you can achieve perfect results every single time. Whether you’re dealing with uneven concrete or simply freshening up tiled floors, this guide will take you through the process step by step.
What is Self-Levelling Compound?
A self-levelling compound is a cement-based material that mixes with water to form a pourable substance perfect for use over a base layer to help build the smooth, level surfaces needed for flooring projects. It spreads easily and flows into low spots for even finishing with less effort than with regular screeds. This makes it perfect for prepping uneven concrete floors or floating over existing tiles for new flooring installation.
Self-levelling compounds work by utilising gravity to spread in thin layers, naturally flowing to fill in low areas and create a level surface. This process helps ensure that the finished floor is smooth and even, reducing the risk of imperfections. Additionally, the flexibility of these compounds allows them to move without cracking, accommodating slight movements in the underlying surface.
These compounds are highly versatile and are suitable for use under tiles, vinyl, and laminate.
Some of the critical advantages include:
- Faster application
- Less labor
- More accurate finish
Whether levelling subfloors as part of a renovation for new tiles or just a flat surface for whatever finishes lie ahead, knowing what self-levelling compound is and how to use self-levelling compound is paramount to achieving professional results.
Lewis Ross, ⭐️⭐️⭐️⭐️⭐️ Google Review:
“The original floor was in terrible shape… but with the skill and knowledge of Alan & Gordon from Next Level Underfloor Heating And Screed Solutions, they left the house perfectly level.“
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Preparing to Use Self-Levelling Compound
How to Determine if Your Floor is Too Uneven for a Self-Levelling Compound
Before proceeding with a floor levelling compound, it’s crucial to assess just how uneven your floor is. If the disparity exceeds 5mm, this might not be the most suitable method. Here’s a step-by-step approach to gauge floor unevenness.
- Initial Assessment with Rolling Objects:
- Use marbles or smooth balls.
- Drop them at various points on the floor.
- Observe where they roll to identify the areas that dip the most.
- Precise Measurement with a Spirit Level:
- Take a 6-foot spirit level and place it across the identified low point.
- Adjust the level until the bubble centres in its vial, ensuring it’s perfectly horizontal.
- Measure the gap under the raised end using a ruler.
- Evaluating the Result:
- If you measure a gap greater than 5mm, consider alternative floor levelling solutions. A traditional self-levelling compound might not provide the stability you need for larger discrepancies.
How to Mix Self-Levelling Compound
We’ve rounded up the main things to know when mixing self-levelling compound. To ensure you get it right, follow these steps:
- Gather Your Tools: Before you start, make sure you have all the necessary tools. You’ll need:
- Scraper
- Filler
- Duct tape
- Primer
- Self-levelling compound
- Mixing paddle
- Large bucket
- Steel trowel
- Spiked roller
- A sturdy drill
- Surface Preparation: Clean the surface thoroughly to ensure the floor is dry and free of dust or debris. Use a scraper and filler to address any imperfections.
- Weigh The Water: Consult the manufacturer’s recommendations for the proper ratio of water to compound. Generally, it’s around 5 to 6 liters of water per 25kg bag of compound.
- Add Compound: While continuously stirring with a mixing paddle attached to a power drill, gradually add the self-levelling compound to the water. This helps prevent clumping.
- Mix It Up: Mix for a good 2-3 minutes until the mix is smooth and lump-free. Be sure to follow the manufacturer’s guidance on mixing time.
- Check Consistency: The compound must be fluid but not too watery. It should be pourable, about as thick as cream. If it’s too thin, it won’t level as it should; if it’s too thick, it won’t spread properly.
Use the compound immediately before it starts to set, usually within 20-30 minutes. And this guarantees the best outcome of your flooring project. Due to its sticky consistency, you need to ensure it is mixed properly for a professional, smooth finish.
How Much Self-Levelling Compound Do I Need?
To find out how much self-levelling compound you will need, gauge the area that you are going to cover. Measure the floor’s length and width, then multiply these numbers to calculate the square footage. Then, think about how thick a layer you will need; you can have between 3mm and 6mm for most floors.
As a rough guide, a 25kg bag of self-levelling compound should cover some 5-6 square metres at a depth of 3mm. If you are wondering how many bags of self-levelling compound you need to buy, take the square footage and divide that by the coverage rate per bag, factoring in how thick you are going to make the application. But always check with the manufacturer for details on coverage.
Is It Necessary to Use PVA Before Applying Self-Leveling Compound?
Using PVA (polyvinyl acetate) before applying a self-leveling compound is not strictly necessary. However, preparing the surface properly is crucial. Here’s what you need to know:
- Surface Preparation: Ensure that the surface is clean, dry, and free from dust or debris. This will help the self-leveling compound adhere more effectively.
- Priming: Instead of using PVA, it’s recommended to use a primer specifically designed for this purpose. Primers improve adhesion and help prevent air bubbles from forming under the compound.
- Considerations for PVA: While PVA can be used in some situations to seal very porous surfaces, make sure it is suitable for the specific materials involved. Not all surfaces respond well to PVA, and its use may not be necessary if a proper primer is applied.
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How to Approach Using a Self-Levelling Compound as a Beginner
Are you new to using a self-levelling compound? Here’s a detailed guide to help you navigate this DIY project with confidence.
1. Understand the Material
Self-levelling compound is essentially a polymer-modified cement with a high flow capacity, making it ideal for correcting uneven flooring. Before you start, familiarise yourself with its properties through online resources or instructional videos from reputable sources.
2. Assess Your Skill Level
If you’re just starting out, it might be wise to consult with or hire a professional. This ensures you achieve the desired results without unnecessary setbacks. Trying it on your own requires confidence in your ability, especially since precise pouring and timing are critical elements.
3. Prepare Thoroughly
Gather essential tools such as a mixing paddle, bucket, and a spreader. Make sure the area is clean and clear any debris beforehand. Mark uneven spots to understand where more material might be needed.
4. Follow Instructions Meticulously
Each product has specific guidelines, and adherence to these instructions is crucial. Pay attention to the mixing ratios and times, as slight deviations can significantly impact the outcome.
5. Practice Patience and Precision
Once you begin pouring, work steadily and evenly to allow the compound to flow and settle correctly. Avoid rushing the process, as hasty application often leads to uneven surfaces.
6. Safety First
Use protective gear such as gloves and goggles to prevent any accidents. Ensure your work area is well-ventilated to avoid inhaling fumes.
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Step-by-Step Guide: How to Use Self-Levelling Compound
How to Apply Self-Levelling Compound on Concrete Floors
1. Prepare the Concrete Surface
The concrete floor should be clean, dry and free from debris before applying the self-levelling compound. Clean off any dust, dirt, or grease that could cause adhesion issues. To get the best results, vacuum or sweep the surface well. If you find any holes or cracks, patch them with a concrete repair filler and allow it to dry.
2. Prime the Surface
Primer is necessary for the self-levelling compound to bond properly with the concrete. Based on the instructions provided by the manufacturer, use a roller or brush to apply a concrete primer. Wait for the primer to dry for the suggested time, which is usually 1-2 hours, before proceeding.
3. Mix the Self-Levelling Compound
Once the primer is dry, mix the self-levelling compound according to the manufacturer’s instructions. You will typically blend the compound with water, but check the packaging for exact ratios. Use a drill with a mixing paddle so you get a consistent, lump-free mixture.
4. Apply the Compound
Mix the compound according to the manufacturer’s directions and pour small sections onto the prepared concrete floor. Begin in a corner and move across the floor. The compound will aerate and level on its own, but if needed, use a spreader or trowel to help move it into position. Be fast, as self-levelling compound can begin to set in about 20 to 30 minutes.
5. Smooth and Level the Compound
As you pour it out, the low spots of the concrete will fill with the compound. Apply a smoothing tool over top of the compound to level it out and to help you reach the thickness you’re looking for.
Let the compound dry and cure before walking on it or applying a new floor covering. This method of how to use self-levelling compound on a concrete floor ensures a perfectly level surface for any type of flooring.
John Keggie, ⭐️⭐️⭐️⭐️⭐️ Google Review:
“Very knowledgeable and professional. I wasn’t sure we could even screed it — but they made it perfect.”
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How to Use Self-Levelling Compound Over Tiles
Proper surface preparation is vital for a seamless application. Here’s how to make and use the compound on tiles:
1. Clean and Prepare the Tiled Surface
Firstly, make sure the surface of the tiles is clear of any grease, dirt or dust. Blow the tiles and rinse off any residue with mild detergent and water. Do not touch the surface until it is dry. Clean out any loose or damaged grout and ensure that there are no high spots or gaps between tiles that might affect how the compound covers.
2. Ensure Tile Adhesion
The tiles need to be adequately attached to the subfloor for the best bond. Re-adhere any loose tiles before proceeding. Fill in any wide grout lines (if applicable) with grout repair or filler for a smooth surface. This is important because self-levelling compound will not bond well to tiles with gaps or loose areas.
3. Prime the Surface
A primer must be used to ensure a good bond between the self-levelling compound and the tiles. Apply a tile-compatible bonding primer and coat the entire surface with a brush or roller. Consult the manufacturer’s instructions for drying times. Priming also allows the compound to stick better and prevents the compound from sliding off the tiles as it cures.
4. Mix and Apply the Compound
When the primer has dried, prepare the self-levelling compound as per the manufacturer’s specifications. Begin dispensing the compound in one corner onto the tiled surface. The compound will then settle into the low spots and even itself out. Guide the compound into place with a smoothing tool or trowel.
5. Allow to Dry
A compound should also be left to set and dry fully before walking on it or installing new flooring. The self-levelling powder will form a flat, smooth surface for new tile, carpet or vinyl.
We hope you have a better understanding of how to use self levelling compound over tiles, and these steps will help you get the best results. For both new installations and right renovations, this process provides a flat and smooth surface to receive any flooring.
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How to Lay Self-Levelling Compound
Installing self-levelling compound properly is the foundation of a smooth, level floor. Here is a breakdown of how to apply self-levelling compound step-by-step like a pro:
1. Prepare the Surface
Clear and dry the floor, making sure that the surface area is free from dirt and dust before you start. Any dust, dirt or grease can impact how well the compound bonds. For optimal performance, clean the floor with a vacuum and repair cracks or holes if necessary. For a porous surface like concrete, use a bonding primer so the compound sticks.
2. Mix the Compound
Prepare the self-levelling compound per the manufacturer’s instructions. With a mixing paddle on a drill, beat until you have a smooth, lump-free consistency. It should be thick but pourable, like heavy cream. Be careful not to mix too much, as this can add air bubbles.
3. Pour the Compound
Working your way back to the exit, begin pouring the self-levelling compound at the farthest corner of the area. For best results, follow the self-levelling compound pouring instructions. Drizzle it in a thin stream, moving across the surface. The compound will work its way and spread out, filling in low spots. Work quickly, as the compound starts to set after approximately 20-30 minutes.
4. Spread the Compound
A spreader or smoothing tool can be used to make sure the compound gets into the corners and along edges. Also, use a long trowel to help smooth your surface. Gently tilt and move the tool without pushing down too hard. The compound will level itself, reducing the amount of spreading that will be required anyway.
5. Check for Air Bubbles
After pouring and spreading, roll the compound with a shaggy roller (also referred to as a spiked roller). It also helps to remove trapped air bubbles and keeps a flat surface.
6. Allow to Dry
Wait until the self-levelling compound is completely dry before walking on it or using flooring. While they dry at varying times, it usually will take a few hours to a day to cure completely depending on thickness and humidity.
By following these steps, you will know how to lay self-levelling compound for a smooth, even floor, ready for your chosen finish.
Reuben Welch, ⭐️⭐️⭐️⭐️⭐️ Google Review:
“Absolutely excellent service from Alan, Gordon and Ryan, right from the initial visit and advice. They prepped the pre-insulated 180sqm floor over multiple rooms and fitted all the heating pipes and manifold in two days. They pumped in the Cemfloor screed on the third morning and it was all done in under three hours. Amazingly neat job, super flat finish, hard enough to walk on after 24hrs (despite being mid-February and quite cold). Highly recommended and stress free!“
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FAQs on Using Self-Levelling Compound
Most common questions our clients ask us when discussing self-levelling compound
How thick you can pour self-levelling compound will vary by product and surface. It is usually applied in layers of 3mm, to 10mm. You can use a thicker application for uneven floors, but be sure not to surpass the manufacturer’s advised max thickness — typically around 10mm.
For a thicker coating, you may need to apply several layers. For minor adjustments, 3-5mm thick is perfect, but for large depressions, you might need to build it up a few times. As always, refer to the product’s instructions for the best outcome.
Self-levelling compound generally dries to the touch in 1-2 hours but can take 24 to 48 hours to fully cure (depending on temperature, humidity, and thickness).
Depending on the thickness of the layer, the time it takes for the self-levelling compound to dry can vary.
Tiling can typically be carried out after 24 hours. Always refer to the manufacturer’s guidelines.
Yes, you can lay self-levelling compound in layers, but it requires proper preparation. Each layer must be carefully cleaned, primed, and abraded before you apply the next one. This ensures adhesion between layers and a smooth, durable finish. Following these preparation steps is crucial to achieve the desired level of flatness and integrity in your flooring project.
You can walk on it 4-6 hours later but do not have heavy traffic until fully cured.
Yes — priming is essential. It improves adhesion, prevents air bubbles, and ensures a consistent, crack-free finish. Most manufacturers recommend using a specific primer suited to your subfloor type (e.g. concrete, tile). Skipping this step increases the risk of poor bonding and early failure.
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Troubleshooting Common Issues
Putting down your compound too thin, drying too soon, and uneven spread are the classic mistakes people make with self-levelling compound. If the compound isn’t spreading evenly, make sure you’re using the right tools and applying it quickly before it begins to set. Do not add excess water when thinning, which alters the compound’s capability to level.
Low humidity or high temperatures can cause the compound to dry out too quickly. To avoid this, work in smaller sections or use a slower-setting product. If you mess up, you can fix it by putting another layer of compound on after the first layer has cured.
To ensure the compound dries properly, it’s crucial to control the environment. Start by making sure the room is well-ventilated and maintains a temperature of around 20 degrees Celsius. This creates optimal conditions for drying without the risk of cracking or crazing.
Be mindful of strong sunlight or cold drafts, as they can lead to uneven drying. If your space has underfloor heating, consider using a latex polymer to prevent potential issues. By taking these precautions, you can achieve a smooth and durable finish.
Conclusion
Self-levelling compounds offer an easy, effective solution for achieving smooth, even floors. By following the right steps, you can ensure professional results every time.
Lewis Ross, ⭐️⭐️⭐️⭐️⭐️ Google Review:
“The original floor was in terrible shape… but with the skill and knowledge of Alan & Gordon from Next Level Underfloor Heating And Screed Solutions, they left the house perfectly level.“
Ready for perfectly level floors? We’re here to help from prep to finish. No guesswork, no stress. For flawless screeding services using self-levelling compound, contact us today and get your free survey, consultation and quote to transform your floors with expert precision and quality. We serve all of Scotland, including Perth, Dundee, Stirling, Glasgow, Edinburgh, etc.
