Each of these is a single-ply membrane: one sheet of material covers the roof, instead of layers of tar and gravel. This guide explains how the three systems differ, where each one fits, and what to ask any contractor before you approve a scope.
At a glance
- TPO is a light-colored thermoplastic membrane with heat-welded seams.
- EPDM is a black synthetic rubber membrane (white versions exist), usually seamed with adhesive or tape.
- PVC is a plastic membrane with heat-welded seams and stronger resistance to grease, oils and many chemicals.
Every system depends on installation quality. A well-installed system of any type will outperform a poorly installed one of a "better" type.
TPO
TPO is the most common low-slope membrane on commercial buildings today. Its light color reflects heat, which can lower cooling demand during Atlanta summers. Its seams are heat-welded, which creates a continuous bond when done correctly.
TPO works well on retail centers, offices, multifamily buildings and general commercial roofs where cost, energy performance and a clean appearance matter. When we evaluate TPO, we check the membrane thickness, the reinforcement, the quality of the welds at every seam and flashing, and whether the existing deck and insulation can support the new layer.
EPDM
EPDM is a synthetic rubber membrane that has been used on commercial roofs for decades. It is usually installed in large sheets with seams bonded by adhesive or tape. It handles movement well and is often a practical choice for lower-slope roofs with many penetrations.
EPDM works well on lower-slope roofs, buildings with many pipes and rooftop units, and replacement projects where the budget is the main constraint. Seams are the most common failure point on EPDM, so we check seam bonding closely, along with the flashings, the drainage, and how the roof is protected from oil, grease or solvents from rooftop equipment.
PVC
PVC is a plastic membrane with heat-welded seams, like TPO. It resists grease, oils and many chemicals better than most membranes, which makes it a strong fit for restaurants, food processing and buildings with rooftop exhaust.
Mosaic is a Duro-Last Authorized Dealer, and Duro-Last is a PVC roofing system. That means we can speak directly to PVC installation details and warranty requirements. We recommend PVC when it fits the building, not as a default.
How to choose between them
1. Start with the building. Is it a restaurant, a warehouse, an office or a multifamily property? Use and exposure matter more than the brand. 2. Look at what sits on the roof. Grease exhaust, chemical vents, HVAC units and foot traffic all change which membrane makes sense. 3. Check the existing roof. Is the deck sound? How many layers are on it? Does it need a full tear-off, or can it be recovered? The answer changes both the cost and the choice. 4. Compare the seams and flashings, not only the membrane. Most leaks start at penetrations, roof edges and seams. 5. Read the warranty. Ask what it covers, what maintenance it requires, and whether the installer is certified for that system. 6. Plan for maintenance. Every membrane needs periodic inspection and drain clearing. A maintenance plan costs far less than an emergency repair.
Questions to ask any contractor
- Which membrane do you recommend for this building, and why?
- Will you tear off to the deck, or recover over the existing roof? What is the decking allowance in the contract?
- How are the seams made, and who inspects them?
- What is the flashing plan at roof edges, curbs and penetrations?
- What warranty do you provide, and what does the manufacturer warranty cover?
- Who will be on site, and who is my contact if the roof leaks?
Next steps
If you are comparing proposals for a commercial roof, or a roof needs a decision, call (404) 260-3168 or request a commercial roof assessment below. We inspect the roof, document the existing system, and explain the options in writing before any work is scheduled.
For buildings with a sound roof, a commercial roof maintenance plan helps extend its life. For active leaks, see our emergency commercial roof repair page.