Japan Metal Building Systems Pvt. Ltd. Supplies Pre Fabricated Conventional Steel Roofing Structures. Japan Metal Building Systems Pvt. Ltd. Manufactures roofing systems, decking sheets, cladding sheets and metal building systems. Pre Fabricated Conventional Steel Roofing Structures is available under one roof, enabling single source accountability. Pre Fabricated Conventional Steel Roofing Structures is tailor made to suit the specific need and end use of the building. The structures are light weight, easy to install with high durability and low-maintenance cost. This steel structures help to reduce construction costs due to the shorter schedule as compared to other building types.