Treatment of wood surfaces with various finish coating materials is recommended for long term protection of wood products exposed outdoor. Due to natural weathering, the colour and the surface roughness of uncoated wood is changed. However, in practice it can happen that wood in constructions has been weathered before to application of a finish. In this work, selected properties of sapwood and heartwood of pine (Pinus sylvestris, L.) surface such as surface roughness and adhesion of coating film were investigated on the surfaces of previous naturally weathered wood Two coating materials useable for wooden constructions in exterior conditions were used: dark brown polyurethane-based system and light brown oil-based surface treatment. The results of pull-off test for adhesion showed that the polyurethane coating film showed the weakest point in the pre-weathered layer of wood substrate and also at the wood/coating interface. The oil-based surface treatment had the weakest place inside the coating film or in the coating penetration layer in the wood substrate. Pre-weathering did not significantly affect the adhesion the coating film on wood. The result of the pull-off test for adhesion of both surface treatments was significantly greater on the heartwood surfaces than on the sapwood surfaces of the sound wood.



















