This paper studies the potential use of coconut husk particles bonded by castor oil-based polyurethane resin to manufacture low-density thermal insulating particle boards, reinforced on their external surfaces by coconut leaf sheaths naturally available in tropical regions as a textile. Panels with a nominal density of 300 kg/m3 were manufactured, and a resin/particle ratio of 0·2 (by weight) was adopted to ensure the necessary adhesion of the particles. The panels under consideration were: plain coir particle boards without tissue reinforcement; one external side reinforced by one layer of the upper parts of leaf sheaths; both external sides reinforced by one layer of the leaf sheath‘s upper parts (UP2S); and both external sides reinforced by one layer of the leaf sheath‘s bottom parts. The thermal, physical and mechanical properties of the boards were evaluated and the thermal-physical-mechanical results indicated that coconut husk particle boards reinforced on both external sides by the upper part of the coconut textiles (UP2S) can be considered for thermal insulation.