The building industry's emphasis on cost-driven standardization has led to more waste, prompting a need for resource-efficient methods. While coreless-filament winding (CFW) with materials like flax fibers show promise, a research gap is present. This study explores how computational design, coupled with coreless-filament winding, can create modular, demountable, and aesthetically valued fiber-based building systems. The methodologies chosen are research-by-design and prototyping, which generates various design options that are supported by literature and insights from an expert in the field. The viability of flax fiber-based building systems, using CFW, relies on the intended function. While flax is optimal for structural and thermally insulated elements, addressing weatherproofing and flammability necessitates a combination of different fiber types in bespoke fibrous tectonic structures.