The purpose of this study was to develop effective green insulation boards fabricated from polyurethane (PU) reinforced with Kenaf fibres. Biocomposites having three different weight contents (40/60, 50/50 and 60/40 Kenaf / PU weight %) were manufactured. A fourth type was made from 60/40 NaOH-treated Kenaf / PU weight %. The results show that the elastic properties increased with Kenaf fibre content. The optimal performance was observed at a weight of 50% Kenaf fibres. In addition, kenaf fibres treated with NaOH exhibited significantly improved mechanical properties.