Built-up
A roof consisting of multiple plies of roof felts laminated together with bitumen. Built-up roof
material can consist of bitumen-saturated felt, coated felt, polyester felt or other fabrics. A
surfacing is generally applied and can be asphalt, aggregate (gravel or slag), emulsion or a
granule-surfaced cap sheet.
Built-Up Roofing is one of the oldest and most reliable ways of installing a new roof. It was first known as composition roofing and started in the 1840's. B.U.R.'s come in two basic types, asphalt and coal tar, and three basic components:
- the waterproofing component
- the reinforcing component
- the surfacing component which is used to protect the other components from the elements
The roofing membrane is protected from the elements by a surfacing layer, either a cap sheet or
gravel embedded in bitumen or a coating material. The most common surface for a BUR system,
particularly in the west, is a fiber glass mineral surfaced cap sheet. The west represents 40 percent
of the fiber glass cap sheet market. It offers a number of advantages. It has a white granular look,
it is cost effective, and is relatively maintenance free.