The building industry is increasingly adopting bio-based materials to meet the growing demand for environmentally friendly alternatives. Composites, known for their diverse properties and adaptable geometries, are gaining popularity as a versatile choice for customising materials for specific applications. This paper presents a 3D scanning methodology to enhance construction accuracy with sustainable building materials. It introduces three fabrication technologies for fibre-reinforced biocomposites and the resulting building components and structures at different scales achieved with each method. Pultrusion is employed to produce natural fibre biocomposite profiles used in an active-bending structural system. 3D Printing (3DP) is utilised to create a modular column using natural fibre-reinforced bioplastic, while Tailored Fibre Placement (TFP) is applied to fabricate biocomposite facade panels with varying geometries. The three case studies demonstrate the use of scanning technology to improve fabrication and assembly processes, with geometric accuracy evaluated through Terrestrial Laser Scanning (TLS) during construction, allowing for a detailed comparison of the built structures with the digital models. Scanning revealed that pultrusion produced accurate components but exhibited up to 160 mm deviations in large-scale freeform assemblies. 3DP can achieve high component manufacturing accuracy with deviations below 5 mm, though modular assembly introduced accumulated errors reaching 40 mm. TFP deviations varied between-48 and 60 mm, with different shaping approaches helping to reduce errors. A comparative analysis of the three methods provides recommendations for improving fabrication and assembly processes while establishing a framework for the future integration of biocomposites as structural components in architectural systems.