Recycling and sustainable production are critical for ensuring a sustainable future. This study aims to develop an environmentally friendly composite utilizing cement paste waste (CPW) combined with methylcellulose, chitosan, and hemicellulose through hot pressing. The mechanical properties of the resulting composites were systematically compared. Specimens were hot-pressed for five minutes and subsequently cured for three days before mechanical strength testing. Results revealed that composites incorporating hemicellulose and methylcellulose exhibited superior flexural and compressive strengths compared to those made with chitosan. Furthermore, the combination of hemicellulose and chitosan produced higher mechanical strength than the mixture of methylcellulose and chitosan, a trend consistent for both flexural and compressive properties. Regarding density, hemicellulose-based composites demonstrated the highest values, which remained relatively unaffected by hot pressing. This research advances the understanding and application of biopolymer-based composites in sustainable construction practices.