Due to permanent presence of water, pools are important to be properly insulated. Failure to insulate will cause water penetration and heat and hence high energy consumption of the whole structure. The XPS insulation boards are installed on floor and retaining walls of the pool and then concrete slabs are placed on top. Finally the waterproof layer together with pool tiles and adhesives are applied. The waterproof layer and the XPS board with its low water absorption will assure very high water-tightness.