What is built-up roofing?

Built-up roofing consists of three core components stacked on top of one another: a base ply layer bonded to the deck, alternating layers of bitumen (tar or asphalt) and reinforcement fabric plies, and a surface layer of hot tar or asphalt topped with mineral aggregate like gravel or crushed stone. The reinforcement material can be organic felt, fiberglass mat, or polyester, depending on the system specification and building requirements.

Contractors spread hot bitumen between each ply, creating a strong monolithic membrane that bridges the entire roof surface. The embedded gravel or aggregate serves dual purposes: it reflects UV rays that would otherwise degrade the bitumen and provides fire protection and foot traffic durability. A typical BUR system has three to five total plies, though industrial or commercial applications may require more.

BUR has been the standard for flat commercial roofing in Georgia and across the South for decades. The system performs well in warm climates and handles standing water that collects on low-slope roof surfaces. However, the membrane is puncture-sensitive if not properly protected, and roof repairs require careful work to maintain waterproofing integrity. Many Georgia contractors who specialize in commercial roofing have decades of experience maintaining and replacing built-up systems on warehouses, office parks, and industrial buildings.