This study investigates whether existing residential buildings can be repaired and maintained with alternative mixes of materials to maximize social, economic, or environmental benefits through a case study of a residential building repair and maintenance projects in Hong Kong. Based on optimization techniques, through a portfolio of materials two of the three objectives in building maintenance works can be achieved: employment generation, lifecycle cost reduction, and carbon emission reduction. These materials are different from the original ones used in the floors, walls, ceilings, waterproofing, and doors. The findings enhance the sustainability performance of the global building construction sector in overcoming the universal barriers to implementing energy-efficient buildings, namely, high initial cost, weak enforcement of government policies, and uncertainty of returns. The prototype model suggests that a portfolio of materials can be constructed to achieve two objectives at any given time, with the third objective acting as a constraint. The optimization techniques enable the global building construction sector to strike a balance among economic, social, and environmental benefits and constraints in maintenance works