Why You Should Avoid Self-Levelling Compounds Over Laminate Flooring

Understanding the Risks of Applying Self-Levelling Compounds Over Laminate Flooring

It is strongly advised to never apply self-levelling compounds directly on top of laminate flooring. Instead, the laminate should be carefully removed to reveal a solid, stable subfloor. Removing the laminate is a straightforward process since it is designed to click together, making it easy to detach. Don’t take shortcuts or attempt to overlay new materials without proper preparation—it’s better to start fresh to ensure the integrity of your new floor.

For those curious about the underlying reasons, here are the key factors:

• Movement and Looseness: Laminate flooring is typically installed as a loose-laid system, meaning it’s not fixed with nails or glue. The interlocking click system holds the boards together, forming a unified surface that can still have some degree of movement. Applying a self-levelling compound on top can disturb this delicate setup.
• Underlay Compression: Usually, laminate floors rest on thin polystyrene underlays, typically 3-5mm thick. If additional weight from the self-levelling compound compresses this underlay, it may lead to cracks or unevenness in the finished surface.
• Moisture Sensitivity of MDF Core: Laminate flooring contains an MDF (Medium Density Fiberboard) core beneath the plastic wear layer. If moisture from the self-levelling compound seeps into the MDF, it can cause swelling, warping, and eventual damage to the flooring. This is a common issue observed in older laminate installations exposed to excessive moisture.
• Maintaining Level Transitions: When installing new flooring, a key goal is to achieve a seamless, flush surface with adjacent rooms or existing finishes. Building up layers on top of laminate can create uneven steps, which are both unsightly and potentially hazardous. Removing the laminate ensures a smooth, level transition.

While layering flooring over existing surfaces might seem tempting, it often leads to complications. However, if you’re determined to proceed regardless, be aware that in construction, there are no absolute rules—only practices that either work or don’t. Experimentation is part of the process, but always weigh the risks involved.