The dearth of construction materials has been the bane of the global construction industry. In a bid to curb this menace, it becomes very imperative to source for construction materials from discarded and least costly materials from raffia, bamboo and coconut fibers. This research investigates the hydrothermal response of plant fiber-reinforced-polyester composites (PFRC). Imperical methods were used to determine the mechanical properties of PFRC (bamboo, raffia and coconut fiber composites), with the usage of Monasanto Tensometer testing machine. All the samples were chemically modified with 12.5g of sodium hydroxide. Numerical and micro-soft excel graphics were used to model compressive responses of the PFRCs. From the analyses, the compressive strengths of raffia, bamboo and coconut composites are 40, 45 and 38MPa respectively.