To Prime or Not to Prime: Making the Right Choice for Self-Levelling Compounds
Deciding whether to apply a primer before using a self-levelling compound can often be a dilemma. Ideally, you want to streamline the process and avoid unnecessary steps. Applying a primer adds complexity, requires selecting the appropriate type, and often involves additional equipment and costs. Therefore, understanding when primer application is necessary is crucial for efficient flooring projects.
Much of this decision hinges on the type of sub-floor and the specific self-levelling compound you plan to use. Personally, I prefer a latex-based, flexible self-levelling compound because it simplifies the preparation process. These compounds typically do not require priming if the subfloor is clean and dry—only a thorough sweep and proper drying are necessary before application.
Recommended Product: Ardex Arditex NA Powder & Latex
One reliable option is the Ardex Arditex NA Powder & Latex self-levelling compound. Available in a 24.5kg package for approximately £59.90, this product is highly versatile. It’s designed to be easy to spread thanks to its latex content, which helps it find its natural level. It is also pre-mixed, making it user-friendly. Each bag contains a tub or bucket-sized quantity, simplifying the mixing process.
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Application Versatility and Substrate Compatibility
Two-part latex self-levelling compounds like Ardex Arditex NA can be applied directly onto a variety of substrates, including:
- Porcelain tiles
- Wooden floorboards (with no gaps, see our guide on plying over floorboards)
- Plywood
- Bitumen
- Asphalt
- Ceramic tiles
- Chipboard flooring sheets
- Concrete
- Screed (sand and cement)
- Terrazzo
- Damp proof membranes
- Underfloor heating systems
- Vinyl tiles
For those skeptical about primer necessity, reviewing the Arditex NA Data Sheet can provide reassurance about its compatibility and performance.
Traditional Self-Levelling Compounds and Primer Needs
Traditional self-levelling compounds, which are mixed with water, are primarily suitable for ground floors with minimal movement. These often require a primer, especially on less porous substrates, to ensure proper adhesion. Common primer options include:
- PVA (Polyvinyl Acetate)
- SBR (Styrene-Butadiene Rubber)
- Specialist primers (more expensive but highly effective)
However, these compounds rely on sinking into the imperfections of the substrate and typically don’t adhere well to non-porous surfaces like glass or polished stone. For example, a water-mixed traditional self-levelling compound on a bitumen or asphalt substrate can fail, flaking off due to poor adhesion. To remedy this, a flexible, latex/cement-based 2-part self-levelling compound like Ardex Arditex NA is recommended, as it adheres well to nearly any surface without priming and remains flexible to prevent cracking even in thin layers.
Conclusion
Choosing between primed or unprimed self-levelling compounds depends on the substrate and the specific product used. Latex-based, two-part compounds offer a simplified, reliable solution that often eliminates the need for priming, saving time and effort. Always consider the substrate’s porosity and movement, and consult product datasheets and reviews to ensure optimal results.