Wood samples treated with new generation preservatives (ammoniacal copper quat (Celcure AC 500), micronized copper quat (MCQ)) and traditional preservatives (didecyldimethylammonium chloride (DDAC), and copper (II) sulfate pentahyrate (Cu(II)SO4 center dot 5H(2)O)) have been studied in accelerated weathering experiments. Changes to the surface of the all weathered samples were characterized by colour change and surface roughness measurements. The results show that the treatment with new generation preservatives (Celcure AC 500 and MCQ) provided less colour change than that of traditional preservatives (DDAC and Cu(II)SO4 center dot 5H(2)O) after an artificial weathering test. The least amount of colour change was found on the surface of Celcure AC 500 treated wood samples after 672 hour exposure time. The wood samples treated with copper-containing new generation preservatives were cured to surface roughness in accelerated weathering experiments. The surface values of pine and spruce wood samples treated with DDAC increased more than that of untreated samples after the accelerated weathering test.