The aluminum base is screwed to a metal frame and then the composite panel is placed in pairs in the grooves of the base. Then an aluminum wedge is placed to the base, which fits to the grooves and makes it impossible to remove or move the panel. The wedge is covered by a composite panel stripe so that its color appears uniform throughout the surface. Alternatively, the wedge cap may be painted in a color similar to the bond. The composite panel has a trowel on its top to drain the water.