Xisanzhuang building materials market. According to Baidu map, the insulation board wholesale market is located in Xisanzhuang building materials market, at the intersection of Shijiazhuang North Second Ring Road and Xisanzhuang Street. The popular term insulation board is the board used to keep the building warm. Insulation board is a rigid foam plastic board made of polystyrene resin, other raw materials and polymers, which are heated and mixed, then injected with catalyst, and then extruded.