The development of Ultra-High Performance Fibre-Reinforced Cementitious Composite (UHPFRC) has enabled the design of lightweight constructions. Although the greenhouse gas emissions of UHPFRC per volume are higher than that of conventional concrete, its use reduces the required amount of material in structures. As UHPFRC is waterproof under service conditions, this material also enhances the durability of structures, significantly decreasing the need for maintenance throughout the service duration. Hence, a cradle-to-grave analysis at the project level is crucial to assess the environmental impact of structural designs. This study proposes a method to evaluate the ecological footprint of structural designs made of UHPFRC using three different time horizons: construction, maintenance, and elimination. The environmental impacts of design alternatives in UHPFRC and conventional concrete are compared using two case studies. The findings indicate that UHPFRC structures lead to a significant decrease in the environmental impacts over the service duration, offering promising results for sustainable construction.