The present study describes the use of reactive UV-absorbers (UVAs) that can be covalently attached to a wood substrate to obtain an improved exterior durability. It has previously been demonstrated that the photostability of wood is increased if the UVA is grafted to the wood surface. The grafting of an epoxide-functional UVA, 2-hydroxy-4(2,3-epoxypropoxy)-benzophenone (HEPBP), to thin veneer wood specimens had a larger photostabilizing effect than if the corresponding UVA without the reactive handle was added to the wood coating. The present study shows that not only the chemical structure of the UVA is important but also how the modification is performed i.e. the reaction procedure. A successful attachment of the UVA depends on both the reaction conditions as well as if other reactive species are present at the same time. The presence of for example a vegetable oil (epoxy functionalized soy bean oil) affects the grafting reaction of the UVA. Details on the effect of reaction conditions, reaction sequences, and presence of co-reactants will be presented.