Monitoring shrinkage in mortar and concrete is crucial for ensuring the integrity and long-term durability of mortar and concrete structures as they undergo various environmental and load-induced stresses. Traditional methods lack real-time precision, emphasizing the need for innovative approaches. This study introduces a 3D-printed strain sensor using conductive thermoplastic polyurethane (TPU) to monitor shrinkage. The sensor’s resistance correlates strongly (R2 > 0.91) with dimensional changes in mortar samples, offering a reliable method for real-time monitoring. Produced with advanced 3D printing, the TPU sensor allows customized and scalable fabrication, proving cost-effective for diverse construction materials. Integration into structures during construction enables continuous monitoring throughout the building’s life cycle, facilitating early issue detection and preventing long-term damage. The adaptability of 3D-printed sensors makes them suitable for various environmental conditions and construction materials, contributing to the advancement of construction monitoring technologies. This study paves the way for smart and responsive materials, promising enhanced resilience, and longevity for construction projects, ultimately ensuring the sustainability and safety of built environments.