The use of local materials developed from natural reinforcements remains a major challenge for many researchers in the development of the industry and the fight against pollution. The wood industry generates large quantities of environmental waste, including Iroko wood. To give Iroko a second life, this study uses Iroko sawdust waste to make an epoxy matrix composite material. The composite was produced using a cold pressing technique based on moving the top and bottom plates to a thickness of 10 mm. On this basis, three particle sizes [t < 0.35[, [0.35–0.63[, and [0.63–1[ were used, as well as three reinforcement (R)/matrix (M) percentages of 50R/50M, 60R/40M, and 70R/30M, where R is the reinforcement percentage and M is the matrix percentage. The physical tests, apparent and real density, porosity, moisture content, water absorption rate, absorption and desorption kinetics, diffusion theory, and activation energy were determined by the gravimetric method. A three-point bending test was carried out in accordance with the ASTM D790 for mechanical tests. The results show that the addition of Iroko particles lightens the material by reducing its density. The hydrophilic nature of Iroko particles increases the absorption rate and porosity, with good diffusion capacity as the particle size and percentage increase. The material produced can be light and porous, with possible applications in thermal insulation. In terms of kinetics, Verma et al.’s model best correlates the experimental desorption points for the 3 isotherms, while Page’s model best correlates the water absorption points. The mechanical results show that Young’s modulus and stress at break decrease with an increase in the reinforcement percentage and particle size. The mechanical results can be used to define the material’s applications in construction and furniture. In accordance with the EN312 standard, the composites produced can be classified as type 2 lightweight materials, suitable for use in dry and damp areas.
