Rusting of Polyurethane (PU) coated steel sample which is used in most of the chemical industries has become a problem requiring necessary attention and corrective prevention method. Composite materials are looked at as the alternatives to address this issue. As these composites are not attacked by the chemicals in the industries, acids in present problem. However, composites have complex manufacturing processes and need high cost. The glass fibre plates, composites, cut in to the necessary lengths and dimensions. Then joined at Web Flange Joint (WFJ) with the help of adhesives to reduce the process complexity and cost. It is observed that Huntsman Araldite gives better results as adhesive to be used at WFJ. This is validated using Finite Element Analysis (FEA) with ANSYS tool. The Hundsman Araldite failure strength is much better at the WFJ area. In addition to this, cleats are used with 4 mm, 12 mm for increasing the WFJ area and improve the load carrying capacity of the composite I- Beam. The results of experiments have clearly shown that the glass fibre immersed in the acidic bath solution for certain period has no reaction as such. Hence shown much improved resistance to acidic attack and no rusting as such. Appreciable correlation between experimental and analytical results indicated improved performance of Composite Beam in given chemical (acidic) environment. It is recommended to use the composite I – Beams in acidic environments in place of steel beams to have improved rusting behaviour and lonf life of the beams.