By replacing conventional concrete moulds with flexible sheets of permeable fabric the construction of optimised concrete elements that provide material savings of up to 40% when compared to an equivalent strength prismatic member is possible. This paper details the results of recent tests undertaken at the Building Research Establishment Centre for Innovative Construction Materials at the University of Bath (BRE CICM) that demonstrate significant additional durability advantages for fabric cast concrete.Using accelerated test methods 50% average reductions in both the non-steady state chloride diffusion coefficient and carbonation coefficients were found when comparing concrete samples cast against permeable and impermeable surfaces. Sorptivity, surface hardness, and scanning electron microscopy tests demonstrate further beneficial changes in the fabric cast concrete. The combined results demonstrate that fabric formwork may be used to create structures optimised for strength and durability.