Abstract: An improvement in a roof structure including a built-up roof located over and above a roof deck and particulate material located over and above the built-up roof and method of preparing such a structure is disclosed herein. This improvement comprises the utilization of a relatively inexpensive, preferably flexible non-insulating sheet material which is located over and against the top surface of the built-up roof between the built-up roof and particulate ballast material. The primary purpose of this sheet material is to protect the built-up roof from the harmful effects of the sun and abrasion from the particulate ballast material. The primary purpose of the particulate material is to hold down the sheet material. In one embodiment, this non-insulating sheet material is substantially completely unattached to the built-up roof and in another embodiment it is attached to the built-up roof, at most, only at discrete spotted locations.