Impact of surface finishing technology on slip resistance of oak lacquer wood floorboards with distinct gloss levels

The choice of surface finishing technology for floorboards can significantly influence the risk of slipping. This study aimed to assess the impact of surface finishing technology on the likelihood of slippage, focusing on lacquered floorboards made of northern red oak (Quercus rubra L.). Four finishing methods were applied to the floorboard surfaces, with the primary distinction between the tested variants being the level of glossiness in the top layer, ranging from 3 to 20 gloss units (GU). To evaluate slip risk, tests were conducted using the British portable skid resistance tester (BSRT), providing numerical values in the form of the British pendulum number (BPN) and the slip resistance value (SRV) for qualitative comparisons. The analyses revealed that depending on the type of lacquered wood surface layer, the difference in BPN could vary from 46% to 77% for dry tests and from 48% to 60% for wet tests. Matte lacquer finishes, specifically at 19 GU, exhibited the smallest slip risk, while glossy finishes (4 GU) demonstrated the greatest slip risk, especially when the surface was wet. In terms of wet test results, the least slip risk, regardless of wood grain direction, was observed for variant No. 4 (low glossiness at 4 GU), with an SRV value ranging from 51 to 53. Conversely, variant No. 1 (high gloss at a mean of 19 GU) recorded the poorest slip resistance properties, with an SRV between 29 and 31. These findings suggest that matte lacquer finishes generally provide a safer option compared to glossy finishes, and the inclusion of brushing during production can enhance slip resistance. Furthermore, the direction of the wood grain was identified as a contributing factor to slip risk, with a 0° grain orientation presenting the highest risk. These insights can be valuable for flooring manufacturers and installers in selecting and applying finishes that effectively minimize the risk of slipping. These findings can be used by flooring manufacturers and installers to select and apply finishes that minimize slip hazard.