Heat insulation material based on the rigid closed-cell (no less than 95%) polyisocyanurate foam (PIR). The boards are laminated with kraft paper, cardboard, glass fibre, aluminum foil or multi-layer laminate (incl. water-resistant foil with paper foundation) and paper laminated with polyethylene. Due to their structure and production features PIR heat insulation boards have low thermal conductivity, low water absorption, high strength, and high fire resistance. PIR thermal insulation boards is a thermal insulation material. Resistant to weather and rot impact, they have extremely long service life (incl. in corrosive environment and under high humidity). When exposed to fire, PIR thermal insulation boards form a graphite protective layer on their surface. It prevents the flame spreading and serves as a reliable protection against further effects of fire.