Metal building insulation systems can be simple using fiberglass insulation glued to vinyl coating. The insulation system drapes over the structural purlins and girts. Insulation fits between these members and the exterior metal panels. The vinyl facing is to the inside showing a tight white vinyl between the support members.  Filling the purlin or girt cavity adds extra R Value, and banding systems hold the additional fiberglass in place. Vinyl can be draped over the steel members to hide them...