The second phase of the Modular Prefab Construction project incorporates Mapefibre ST 40 Plus macro-synthetic fibres into precast modular slabs made of concrete-and-timber to reinforce the concrete, while also enhancing its mechanical performance, sustainability and modularity. Using Mapefibre ST 40 Plus reduces the need for conventional reinforcement, promotes a circular economy and simplifies the precast production process. Presented at the fib 2025 symposium, the project provides an innovative solution for the future of construction.