Is PVA Primer Necessary Before Using Self-Levelling Compound?
Generally, applying PVA primer is not a mandatory step prior to laying self-levelling compounds. Nonetheless, it is essential to consult the specific product’s Data Sheet provided by the manufacturer. These documents are typically available on the manufacturer’s official website and contain crucial preparation instructions for the substrate.
Risks and Considerations When Using PVA
Applying a PVA primer poses minimal risk as it is largely inert and water-soluble. The primary concern is the potential waste of time and resources if applied unnecessarily, or the possible damage to your roller if not used correctly.
Advantages of Using PVA Primer
- Sealing Dust and Debris: PVA helps to lock in loose dust and debris, creating a cleaner surface for subsequent layers.
- Preventing Pin Holes: It forms a smooth, sealed layer over porous surfaces like concrete and screed, reducing the risk of pinholes in the finished surface and promoting an even application of the self-levelling compound.
In summary, if you have a PVA mixture available, dilute it with four parts water and apply it to the substrate. Otherwise, always check the manufacturer’s Data Sheet, as many high-quality self-levelling compounds do not require a primer. For instance, I recommend Arditex NA self-levelling compound, which can be used directly over virtually any substrate without the need for a primer, and provides excellent adhesion and surface smoothness.
Should You PVA Tile Floors Before Self-Levelling?
There is generally no need to apply PVA to tiled surfaces prior to self-levelling, as it offers little benefit on non-porous materials like ceramic or porcelain tiles. Instead, if you wish to improve adhesion, you should create a key on the tile surface by using an abrasive grit. Products like Blue Grit, which contain grit or roughening agents, can be applied to tiles to increase surface grip and ensure better adhesion of the self-levelling compound. For example:
- Blue Grit – Extra Grip Plaster Bonding Agent: A 10-litre container costing approximately £24.30, suitable for use on non-porous surfaces such as floor tiles, porcelain, terrazzo, quarry tiles, and ceramic tiles.
This method helps to create a roughened surface that significantly improves adhesion, ensuring a durable and level finish.