Cellular Pvc Siding Reviews . Azek is light and strong in comparison to other types of siding. To give you an idea, hardie shake in our area is $165/ square. James Hardie Siding The Window and Siding Source of St. Louis from www.thewindowandsidingsource.com It’s called celect® cellular composite siding by westlake royal™. Royal celect siding only offers 20 colors. Our cellular siding systems can be fixed vertically, horizontally or diagonally and are available in four styles: