Not normally, however when installing in a wet room (such as a shower, for example), apply a line of silicone sealant to the tongue and groove connection between the panels to ensure a completely waterproof joint. Also apply a line of silicone sealant between the panel and the edge of the shower or bath, and on inside corners. The sealant we recommend is SilTex 40. For Canadian customers, Kwick Seal Plus. Be sure to read the sealant or adhesive instructions before use.