Single-ply roofing membranes are factory-manufactured membranes that are sheet-like. There are two types of single-ply membranes: thermoplastic or thermoset. Thermoplastic materials can be softened when heated and hardened when cooled.
Single-ply roofing membranes are produced using one of three manufacturing processes: calendering, extruding or spread coating.
Single-ply membranes can be installed fully adhered, mechanically attached or held down with ballast. Most single-ply roof systems do not receive surfacings.
Thermoplastic Olefin (TPO)
TPO sheets are a blend of polypropylene and ethylene propylene polymers and usually are reinforced with polyester. TPO sheets contain colorant, flame retardants, UV absorbers and other proprietary substances to achieve desired physical properties. TPO membranes usually come in white or black.
Ethylene Propylene Diene Monomer (EPDM)
Thermoset membranes incorporate principal polymers that are chemically cross linked or cured. One characteristic of true thermoset polymers is once they are cured, they only can be bonded to simliar materials with adhesives.
The most common thermoset roof membrane is EPDM. EPDM principally is composed of two compounds, ethylene and propylene, that are derived from oil and natural gas.
Contractors commonly call these membranes “rubber” roofs.
A roofing square is equal to 100 square feet. The “slope” or “pitch” refers to the incline on the roof. Generally interpreted as the number of inches rise per 12 inches horizontal. 2/12 means that there is two (2) inches rise per twelve (12) inches horizontal.