Harnessing Rice Husk and Water Hyacinth: Developing a Sustainable Thermal Insulated Ceiling Board

This study addresses the urgent need for sustainable construction materials by investigating agricultural and aquatic waste—specifically rice husk and water hyacinth—as inputs for thermally insulating ceiling boards. Rising global temperatures and energy demands motivate the search for eco-friendly substitutes for conventional building materials; in climates like the Philippines, improving indoor thermal comfort affordably is especially urgent. The experimental methodology involved preparing six composite mixtures of rice husk and water hyacinth in varying ratios (three replicates each, total n=18 boards) and casting them in molds for curing. The fabricated samples were tested using a 250W heat lamp for thermal conductivity and a controlled 24-hour water submersion for moisture absorption. The results demonstrate that a 60:40 rice husk-water hyacinth blend yielded the lowest average temperature rise, indicating superior insulation performance. The 60:40 composite's thermal resistance was comparable to or exceeded that of a 100% control board. Moisture absorption of the composite boards remained moderate, and most samples maintained structural integrity with no visible cracks, exhibiting acceptable color and odor for interior use. Overall, these findings indicate that the 60:40 mixture is the optimal blend in terms of combined thermal, moisture, and practical performance. An economic analysis confirmed that the 60:40 boards are cost-effective compared to conventional ceiling boards. In conclusion, the 60:40 rice husk-water hyacinth composite ceiling board emerges as a promising sustainable alternative to traditional ceiling boards. It combines effective thermal insulation, adequate durability, and economic advantage, offering an affordable indoor insulation solution aligned with sustainable architectural design principles.