TPO Roofing Glossary

Reflectivity refers to TPO roofing’s ability to reflect solar radiation rather than absorbing it as heat. TPO membranes, especially in white or light colors, have high solar reflectance values, meaning they bounce sunlight away from your home. This reflective property keeps your roof surface cooler, reduces attic temperatures, lowers air conditioning costs, and can extend the lifespan of your roofing system.

The substrate is the structural surface upon which the TPO roofing system is installed. This foundation layer might be plywood, oriented strand board (OSB), concrete, or another existing roof deck. The substrate must be clean, dry, and structurally sound before TPO installation begins, as any defects in the substrate can compromise the performance and longevity of the entire roofing system.

Insulation board refers to the rigid foam panels installed between the substrate and the TPO membrane. These boards provide thermal insulation to improve your home’s energy efficiency, create a smooth surface for membrane installation, and add protection to the roof deck. Common insulation types used with TPO include polyisocyanurate (polyiso), expanded polystyrene (EPS), and extruded polystyrene (XPS).

Flashing consists of TPO membrane pieces or metal components specially fabricated and installed around roof penetrations, edges, corners, and transitions. Properly installed flashing prevents water from entering your home at vulnerable points such as vents, chimneys, skylights, and parapet walls. TPO flashing is typically heat-welded to the main membrane, creating seamless water protection throughout the entire roof system.