Anti-slip properties of thermally modified hardwoods

The impact of thermally modified wood on slip resistance remains uncertain, despite its popularity as a flooring material. This research investigates the influence of modification temperature, wood species, and wood grain orientation (tangential vs. radial) on the slip resistance of thermally modified wood used for flooring. The study also explored the potential influence of wood grain orientation (tangential vs. radial) on slip resistance. Three commonly used flooring hardwoods (oak, ash, and beech) were tested. For each investigated wood, clear samples were prepared with tangential and radial grain orientations and subjected to three treatments: unmodified (control), thermally modified at 190 °C, and thermally modified at 212 °C. A slip risk was measured using a British Skid Resistance Tester. The results showed that ash and beech exhibited significantly better slip resistance than oak. Wetting the surface significantly increased slip risk for all wood species. Thermal modification has a complex effect: In dry conditions, it slightly improves slip resistance, while in wet conditions (more relevant for flooring safety), it worsens slip resistance, particularly at higher modification temperatures. The results suggests that thermal modification improves slip resistance but is not a guaranteed method for improving slip resistance in wood flooring. It might even be detrimental in areas with potential water exposure. Other factors, such as wood species and surface treatments, should be considered for optimal slip resistance in flooring applications in areas with potential water exposure.