Installing Floor Self-Levelling Over Slate Tiles: A Comprehensive Guide
- Imperial Flooring Australia
- Nov 20, 2025
- 2 min read
Updated: Dec 5, 2025
Can You Pour Floor Self-Leveller Over Slate Tiles?
Yes, you can, provided the slate is structurally sound, properly prepped, and primed. Self-levelling is often used over slate to:
Correct uneven or riven surfaces
Strengthen the subfloor before installing new flooring
Improve acoustic and structural performance
Create a smooth, bond-safe surface for adhesives or underlay
Step-by-Step: How to Install Self-Levelling Over Slate Tiles
1. Inspect the Slate Tiles
Before anything else, check that the slate tiles:
Are firmly bonded
Have no hollow or drummy sounds
Are not cracked, crumbling, or lifting
Any loose or damaged tiles must be removed or repaired before levelling.
2. Thoroughly Clean and Degrease
Slate can hold dust, grout haze, oils, and contaminants. A clean surface is essential for adhesion.
Sweep and vacuum
Scrub with a heavy-duty degreaser
Rinse well and allow to dry completely
3. Apply a Bonding Primer
Priming is crucial over slate tiles and must not be skipped. Use a high-adhesion primer designed for non-porous or low-porosity surfaces. Apply with a roller or brush and allow to dry per manufacturer instructions.
The primer:
Improves adhesion
Seals the slate
Ensures a consistent bond with the levelling compound
4. Mix the Floor Self-Levelling Compound
Follow the exact water-to-powder ratio on the bag. Overwatering can weaken the compound and lead to cracking.
Use:
A clean bucket
Cold, fresh water
A high-powered drill with a mixing paddle
Mix until smooth and lump-free.
5. Pour and Spread the Compound
Start at the farthest point from your exit path.
Pour the DL59 Cemimax floor leveller onto the slate.
Use a smoothing trowel or gauge rake to help it flow.
Allow the product to naturally self-level and guide to the set heights required. Note it will not self-level and fix itself—so set it out first.
Feather edges where needed.
Work fairly quickly, as most levellers begin to set within 10–20 minutes.
6. Allow Proper Dry Time
Drying time varies based on:
Temperature
Humidity
Product brand
Pour depth
Most self-levellers allow light foot traffic after 3–6 hours, but always confirm the manufacturer’s schedule before installation.
7. Check for High Spots and Flatness
Once fully cured, check the surface using:
A 2m straight edge
Laser level
Do a light sand if necessary to remove minor imperfections.
Common Mistakes to Avoid
Skipping primer
Pouring over loose or damaged tiles
Overwatering the leveller
Pouring too thick without multiple layers
Not cleaning or degreasing properly
Why Proper Levelling Matters Before Laying New Flooring
A flat, stable substrate ensures:
Longer flooring lifespan
Better click-system alignment
Reduced noise, movement, and deflection
A premium finished result
Whether you’re installing laminate, hybrid, engineered timber, or carpet tiles—proper levelling is essential.
Conclusion: The Importance of a Solid Foundation
In summary, laying new flooring over slate tiles requires careful preparation. By following these steps, you can ensure a smooth and durable base for your new flooring. Remember, the key to success lies in proper inspection, cleaning, and levelling. A well-prepared surface will lead to a better finished product, enhancing the overall aesthetics and longevity of your flooring.
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