Horizontal Shadow Gap Timber Cladding Green Treated (European Redwood)Green treated horizontal shadow gap cladding. Horizontal shadow gap cladding profile is a modern and contemporary profile which produces a soft V shape shadow effect. The profile allows hidden fixings by having an extended top half to the rear of the piece this means nails and screws can be covered over after fixing. Horizontal shadow gap is a very popular profile which tends to look more traditional and works well on short, wide buildings.