Degree of surface quality of wood plastic composites (WPCs) is a function of both raw material characteristics and the manufacturing variables. The WPC panels comprised of different panel densities (800, 950, 1000, and 1080 kg/m(3)), wood flour contents (50, 60, 70, and 80 wt.%), wood flour sizes (<0.5, >= 0.5 to <0.8, 0.8-1, and >1 mm), and hot-pressing temperatures (190 and 210 c) were manufactured using a dry blend/flat-pressing method under laboratory conditions. The surface smoothness of the WPC panels improved with increasing WPC density, plastic content, and hot-pressing temperature while it deteriorated with increasing wood flour size. The reduction in the particle size of the WF resulted in a more compact structure on the WPC surface. In general, the wettability of the samples increased by increasing surface roughness. (C) 2011 Elsevier Ltd. All rights reserved.