Commercial facilities with flat roofs require a different roofing solution than steep-sloped buildings that traditionally use asphalt shingles or architectural metal systems for protection from the elements.

Built-up roofing (BUR) systems are so-called because they are literally constructed on the rooftop by “building” alternate layers (plies) of asphalt and reinforcement fabric. They’re usually topped with a layer of stone or gravel. Built-up systems have been in use for well over a century.

In recent decades, advances in chemical and manufacturing technology have enabled the development of single-ply membrane systems; flexible sheets of synthetic materials manufactured from a variety of chemical components. Here are some of the most common:

Modified bitumen systems have a composition like built-up roofing – but made in a factory. They’re layers of asphalt that also include synthetic materials and a fabric layer for reinforcement.

Thermoset membranes (primarily EPDM today) are vulcanized materials (rubber) made from cross-linked molecules that provide elasticity. Once the material is “set,” it’s hard to bond and can’t be heat-welded; EPDM membranes require adhesives for installation seaming.

Thermoplastic membranes (PVC, TPO, and some others), first used in Europe in the 1960s, do not contain cross-linked molecules, so they do not “set.” These materials “flow” when heated, enabling membrane sections to be heat-welded together during installation.

Regardless of the type of system you choose, commercial roofing projects can be highly complex. Make sure that your contractor is experienced with all the technology involved.

At Tusing Builders & Roofing Services, we’re experts in installing several types of roofing systems. We would welcome the opportunity to prepare a quote for you. Reach out to us at 866-584-2712.