Due to the non-homogeneity of timber material, the roughness profile of a board is affected by the wood anatomy, thus making the analysis of timber surface quality quite complicated. Currently, there is no reliable method to analyse timber surface quality independent of the timber species or timber properties. The current standard filtering methods used to determine the surface roughness profile from a measured profile or a primary profile fail to produce reliable results in timber surface analysis. This paper proposes a new approach to overcome this shortcoming and to provide more accurate and reliable timber roughness analysis methods. The proposed methods are compared with the current standard methods using data from 35 samples of Messmate (Eucalyptus obliqua) sanded with seven different grit sizes of abrasive (P60, P80, P100, P120, P150, P180 and P240). The results suggest that the proposed methods are more consistent and accurate in describing sanded timber surface quality.