Kelampayan (Neolamarckia cadamba) is used in the production of wood-wool cement board (WWCB). The properties of the boards from one type of fast growing timber species were compared by using lower aspect ratio of woodwool of various sizes (1.5 mm, 2.5 mm and 3.5 mm) with fixed water: cement ratio. Wood-wool was pre-treated by soaking it in cold water for 24 hours and was used to produce WWCBs. Portland cement was used as a hydraulic binder with water and wood-wool in the ratio of 2:1:1 respectively per weight of WWCB. A total of 162 specimens were prepared and tested on their physical and mechanical properties according to ASTM D1037 (1998) and MS 934 (1986). Experimental investigations were conducted to assess the impact of woodwool size and WTVCB thickness on the properties of WWCBs namely flexural strength (Modulus of Rupture, Modulus of Elasticity), compressive strength, internal bond strength, thickness swelling and water absorption. All WWCBs were produced under the maximum requirements in accordance to international standards for cement-bonded particleboard composite (ISO 8335. 1987and the MS 934, 1986). However, 1.5 mm wood-wool and 25 mm WWCB are more stable because it had lower percentage of thickness swelling and water absorption than 2.5 mm and 3.5 mm board. The results showed that the performance of WWCB with a decrease in wood-wool size provides an optimum value for flexural strength (MOR and MOE), internal bond and also density. In terms of WWCB thickness, the results showed that the mechanical properties of WWCB are greatly influenced by the density - as the density increases the mechanical strength also increases. The properties of the composite strength are not in the same trends and are subjected to the type of load conditions. The compressive strength increases when using thicker boards (50mm and 75mm), however the Modulus of Elasticity (MOE) and Modulus of Rupture (MOR) declined as the thickness of the board increases.