TPO vs EPDM: Choosing the Right Commercial Roofing System

When it comes to flat and low-slope commercial roofing, TPO (Thermoplastic Polyolefin) and EPDM (Ethylene Propylene Diene Monomer) are two of the most widely installed single-ply membrane systems in the industry. Both offer reliable waterproofing and proven performance, but they differ in important ways that can significantly affect your building's long-term costs, energy consumption, and maintenance requirements.

At Windward Roofing & Construction, we have installed thousands of TPO and EPDM roofs across Illinois, Wisconsin, Michigan, Indiana, and Florida over the past 40 years. This guide draws on that hands-on experience to give you a clear, honest comparison of these two systems so you can make a confident investment decision.

What Is TPO Roofing?

TPO is a thermoplastic single-ply roofing membrane made from a blend of polypropylene and ethylene-propylene rubber. It is manufactured in white, gray, or tan sheets and installed by mechanically fastening or fully adhering the membrane to the roof substrate. The seams are heat-welded using hot-air welding equipment, creating a bond that is stronger than the membrane itself. TPO gained widespread adoption in the early 2000s and has since become the fastest-growing segment of the commercial roofing market due to its combination of energy efficiency, durability, and competitive pricing.

What Is EPDM Roofing?

EPDM is a synthetic rubber membrane that has been a staple of commercial roofing since the 1960s. Available primarily in black (though white versions exist), EPDM is manufactured in large sheets that can cover significant roof areas with fewer seams. The membrane is typically installed using adhesive bonding or mechanical fasteners, with seams sealed using specialized tape or liquid adhesive. EPDM's six-decade track record makes it one of the most proven and trusted roofing materials in the industry.

Pros and Cons: TPO

Advantages of TPO:

• Superior energy efficiency. TPO's white reflective surface meets ENERGY STAR requirements and can reduce cooling costs by up to 30 percent, making it an excellent choice for buildings with high air conditioning demands.
• Heat-welded seams. Hot-air welded seams create a monolithic, watertight bond that outperforms adhesive-based and tape-based seaming methods in both strength and longevity.
• Chemical and UV resistance. TPO resists degradation from ultraviolet radiation, ozone, and many chemicals, performing well in environments near restaurants or industrial operations.
• Competitive cost. TPO delivers performance comparable to PVC roofing at a lower material cost, offering strong value for budget-conscious property owners.

Disadvantages of TPO:

• Shorter track record. With widespread use beginning in the early 2000s, TPO does not yet have the multi-decade field performance data that EPDM has accumulated.
• Formulation variability. Early TPO products from some manufacturers experienced premature failures. Modern formulations have addressed these issues, but it remains important to choose a reputable manufacturer and certified installer.
• Requires specialized welding equipment. Proper installation demands trained technicians with hot-air welding equipment, making contractor selection critical.

Pros and Cons: EPDM

Advantages of EPDM:

• Proven longevity. EPDM roofs routinely last 30 years or more when properly maintained. Its track record is the longest of any single-ply membrane system.
• Excellent flexibility. EPDM remains pliable at extremely low temperatures, making it well-suited for Midwest climates where winter temperatures regularly fall below zero.
• Lower upfront cost. EPDM is generally the least expensive single-ply membrane to install, making it attractive for large roof areas where budget is a primary concern.
• Simple repairs. Damaged areas can often be patched quickly with EPDM adhesive and membrane patches, reducing downtime and repair costs.

Disadvantages of EPDM:

• Lower energy efficiency. Standard black EPDM absorbs solar heat rather than reflecting it, increasing cooling costs during warm months. White EPDM is available but at a premium.
• Adhesive-based seams. Seams rely on adhesive or tape rather than welding, which can be more susceptible to failure over time compared to heat-welded TPO seams.
• Shrinkage potential. EPDM membranes can shrink over time, particularly if the original installation did not adequately account for membrane movement. This can stress flashings and edge details.

Cost Comparison

For a typical commercial roof installation in the Midwest, EPDM installed costs range from approximately $5.50 to $8.50 per square foot, while TPO installed costs range from approximately $6.00 to $10.00 per square foot. These figures include membrane, insulation, fasteners, flashings, and labor. The actual cost for your project will depend on roof size, complexity, access conditions, insulation requirements, and local labor rates.

While EPDM wins on upfront cost, TPO often delivers a lower total cost of ownership over 20 to 30 years when energy savings are factored in. Buildings with significant cooling loads in particular benefit from TPO's reflective properties, which can save thousands of dollars annually in reduced electricity consumption.

Lifespan and Durability

EPDM holds an advantage in documented longevity. With roofs in service since the 1960s, there are countless examples of EPDM systems performing well beyond 30 years. TPO's expected lifespan is 20 to 30 years, though this figure continues to improve as manufacturers refine their formulations and increase membrane thicknesses. Both systems require regular maintenance to achieve their maximum service life, including biannual inspections, drain cleaning, and prompt repair of any damage.

Energy Efficiency

TPO is the clear winner in energy efficiency. Its white surface reflects solar radiation and meets ENERGY STAR cool roof requirements out of the box. In hot climates or on buildings where cooling represents a major operational expense, TPO can meaningfully reduce energy consumption. Standard black EPDM absorbs heat and offers no reflective benefit. White EPDM is available but adds cost and still does not match TPO's reflectivity. For buildings in Florida or those with large HVAC loads in Illinois summers, TPO's energy performance is a significant advantage.

Climate Considerations: Midwest Winters and Florida Heat

Windward Roofing operates across a diverse range of climates, from the brutal winters of Chicago and Milwaukee to the year-round heat and hurricane exposure of South Florida. Both TPO and EPDM perform well in extreme conditions, but each has strengths suited to specific environments.

Midwest winters: EPDM's exceptional low-temperature flexibility gives it an edge in regions with severe freeze-thaw cycles. The membrane remains pliable and resists cracking even at temperatures well below zero. TPO also performs adequately in cold weather but is somewhat stiffer at very low temperatures. Both systems must be properly detailed and maintained to handle snow loads, ice dams, and the thermal expansion and contraction cycles that are a constant in the Midwest.

Florida heat: In Florida, TPO's reflective surface provides a measurable advantage by reducing roof surface temperatures and cooling costs. Additionally, modern TPO formulations offer strong UV resistance suited to Florida's intense sun exposure. EPDM can perform well in Florida, but its heat-absorbing black surface works against building owners who are trying to reduce air conditioning expenses. For new construction and reroofing in Florida, TPO is frequently the preferred choice.

Which System Is Best for Your Building?

The right choice depends on your building's specific circumstances. Here are general guidelines based on our decades of experience:

• Choose TPO if energy efficiency is a priority, your building has high cooling costs, you are located in a warm climate like Florida, or you want the strongest possible seam performance from heat-welded construction.
• Choose EPDM if upfront cost is the primary driver, you are roofing a very large building where material savings add up quickly, you value a system with the longest proven track record, or your building is in a cold climate with minimal cooling loads.
• Consider both if you have multiple buildings across different climates. Many of our clients use TPO on their Florida properties and EPDM on their Midwest facilities, optimizing each roof for its specific environment.

Regardless of which membrane you choose, the quality of the installation is the single most important factor in your roof's long-term performance. A poorly installed TPO or EPDM roof will fail prematurely, while a properly installed system from a certified contractor will protect your building for decades. Windward Roofing & Construction maintains manufacturer certifications from Carlisle, Versico, Elevate, Johns Manville, and other leading producers, ensuring your roof is installed to the highest standards and backed by comprehensive warranty coverage.

Ready to determine which system is the best fit for your commercial property? Contact Windward Roofing for a free consultation and site assessment. Our team will evaluate your building, discuss your priorities, and provide a detailed recommendation tailored to your needs.

Frequently Asked Questions