Top hydrophobic layer can increase durability of exterior coatings on wood. Two hydrophobic topcoats—synthetics and water-based acrylate resin with wax additives were researched as top layer on twenty-four different coating systems applied on oak wood in this experiment. Artificial accelerated weathering lasted six weeks. Changes of color, gloss, surface wetting were evaluated, and microscopic analyses of coated surfaces were done. The results have shown that top hydrophobic layer increases durability of tested coating systems in most cases. However, the effectiveness of the two researched hydrophobic topcoats was different depending on the specific tested coating systems.