In response to the urgent need for innovative and sustainable solutions in the construction industry, this study provides an in-depth investigation and experimental evaluation of the thermal, mechanical, and chemical properties associated with the incorporation of three different categories of waste into mortar. These categories include expanded polystyrene waste (EPSW), expanded perlite waste (EPW), human hair waste (HHW), textile fiber (TFW), and paraffin waste (PW). Various samples were prepared by adding different proportions of these waste materials as sand substitutes in cement mortar. To enable a thorough assessment of the material properties, a comprehensive series of tests were carried out, including measurements of thermal conductivity, flexural strength, compressive strength, chemical composition and crystalline structures. The results revealed that, for a replacement level of 50%, there was a decrease in thermal conductivity by 28%, 55%, 44% and 67% for EPSW, EPW, TFW, HHW and PW mortars, respectively, which resulted in a decrease in compressive strength by 75%, 71%, 50%, 79% and 81%, respectively. Furthermore, the chemical characterization showed that the chemical composition of the mortar remained consistent, even when a substantial proportion of waste materials was introduced. The study emphases the sustainable construction key role in reducing building life cycle emissions.