China wooden treads circular staircase manufactory supply WilliamArchi create an amazing elegant, modern,high quality wooden treads circular staircase.You can customize outdoor helix spiral staircase according to your requirement for your building project with my professional stair manufacturer. Please see details information of option parts of spiral staircase for your reference. This spiral staircase consist with side stainless steel plate stringer and central post. Wooden treads circular staircase Information WilliamArchi spiral stair frame is easy to fit into small space. Spiral staircases save valuable square meters because they occupy a much smaller area than a conventional staircase. Height of spiral staircase based on your job site. The staircase width normally is between 760mm to 1200mm(30" to 47-1/4"). Dimensions will vary according to measurements of stairs. Spiral staircase consists of central post beam, treads, stair fence, spiral handrails.