This study investigated the feasibility of utilizing paper sludge (PS) as feedstock in the production of composite boards thatare lightweight, durable and environmentally friendly. PS samples were collected from recycled newsprint (RN), corrugatedrecycled (CR) and virgin pulp (VP) pulping mills in South Africa. The PS was dried and mixed with magnesium phosphatecement to produce boards in a central composite design. Three different fillers including fly ash, calcium carbonate and silicafume were also added to the mix as binder replacement. The PS was characterized before use, and the produced compositeboard was evaluated for mechanical and physical properties. The boards produced had medium to high density (0.52—1.12 g/cm3) that could be used for non-structural interior applications. The results showed that boards containing RN had the highestmean value for modulus of elasticity (MOE) of 769 MPa. The mean MOE for boards containing CR- and VP-PS was357 and 411 MPa, respectively. Calcium carbonate had the best effect on the board properties. Techno-economic analysiswas simulated for four different types of feedstock scenarios at different locations including a combined scenario. Sensitivityanalysis revealed that decreased feedstock cost resulted in decreased minimum required selling price. The analysis alsorevealed that the combined scenario proved to be the most cost-effective and profitable option for the future.