Rear Yard. It means that all the components are shipped to the site and are assembled and erected at the site with the nuts bolts and anchor bolts. These Buildings are also known as Pre Engineered Metal Buildings. What distinguishes them from other buildings is that the contractor also designs the building – a practice called design & build. This style of construction is ideally suited to industrial buildings and warehouses it is cheap, very fast to erect, and can also be dismantled and moved to another site – more on that later.