TPO: a thermoplastic membrane with welded seams
TPO roofing uses thermoplastic polyolefin membrane. GAF identifies heat-welded seams as a feature of its TPO systems, while Johns Manville lists multiple attachment approaches and system components. The proposal should identify the actual membrane and the method of attachment.
Ask how insulation, cover board, perimeter attachment and equipment flashing are specified. A membrane thickness alone does not describe the rest of the roof.
PVC: assess the specific formulation and exposure
PVC is also a thermoplastic roofing membrane with heat-weldable products. Manufacturers offer different formulations, including products modified with KEE. Johns Manville documents chemical resistance for specific PVC products, which can be relevant where equipment discharges affect the roof.
Give the manufacturer the actual substances and exposure conditions for review. Do not turn “chemical resistance” into a claim that PVC tolerates every grease, solvent or industrial discharge, or that cleaning and spill control are unnecessary.
EPDM: match the seam and repair materials
EPDM is a rubber-based membrane family. Johns Manville offers purpose-made seam tape and accessory systems for its EPDM roofs. Its seam approach differs from the thermoplastic heat-welded seams discussed above.
For an existing EPDM roof, identify the manufacturer and assembly before specifying repairs or a coating. Do not substitute a product intended for a different membrane because it appears similar.
Compare the assembly and project team
Request alternatives using consistent assumptions for deck condition, insulation, drainage, details and building use. Then compare installation logistics, maintenance access and the actual warranty documents.
- Which exact membrane, reinforcement and thickness are proposed?
- What substrate and attachment method does the assembly require?
- How will seams and transition details be checked?
- What exposure or compatibility questions remain?
- Is the proposed installer eligible for the specific manufacturer program and warranty?
Turn the comparison into a scope
AmeriConstruction provides commercial TPO, PVC and EPDM roofing services. Begin with an assessment of the existing roof and a comparison of complete assemblies. Confirm the named products, qualified service provider and any manufacturer or written warranty requirements for the actual proposed scope.
For the proposed system, confirm the exact manufacturer, installer requirements and written warranty terms before authorizing work.