Asphalt is an aliphatic compound and in almost all cases a byproduct of the oil industry. Some asphalt is manufactured from oil as the intended purpose, and this is limited to high-quality asphalt produced for longer lasting asphalt built-up roofs (BUR). Asphalt roofs are also sustainable by restoring the life-cycle by making repairs and re-coating with compatible products.
Asphalt BUR is made up of multiple layers of reinforcing plies and asphalt forming a redundancy of waterproofing layers. The reflectivity of built up roofs depends on the surfacing material used. Gravel is the most common, with asphalt surfacing and reflective coating options available.