Traditionally, architectural materials performance was the key point for developing materials; but nowadays, other criteria’s as sustainability, availability and recyclability are being considered. By the other hand, the addition of fibres as polymers, steel or glass on cement based materials was proved to enhance their performance in terms of ductility, tensile strength, toughness, fatigue strength, impact resistance and energy absorption capacity of matrices. Actually, the use of vegetable fibres as reinforcement for cement composites is particularly attractive since they are widely available, are biodegradable, and inexpensive. The attractive mechanical and physical properties joint to their environmental benefits combination are the main drivers to use them as alternatives for conventional reinforcements. Bio-fibres as flax fibres have been large used mainly for automotive products. Plus other mentioned properties, the low density of these vegetable fibre composites induces to consider them as an interesting architectural material for envelope skill applications. This research deals with the manufacturing of façade pieces from white Portland cement and treated flax nonwoven fibre composites. The study of the physical properties, i.e. flexural, water permeability, dimensional change of these façade components were also analysed before and after 60 days outdoor exposition