The color combination of grey and walnut for decking can create a stylish and sophisticated look. The grey provides a cool, modern feel while the warm tones of the walnut add depth and richness to the overall look. This color combination can create a unique and eye-catching contrast that can elevate the aesthetic appeal of any outdoor space. It also has the added benefit of being versatile and complementary to a variety of design styles, from contemporary to traditional. Overall, the grey and walnut decking color combination can add a touch of elegance and luxury to any outdoor area.