TPO and EPDM are two of the most common materials used in modern commercial roofing. Both are categorized as single-ply membranes (meaning they are single-layer roofing systems) and are best known for being cost-effective, lightweight, and easy to install. This post highlights the pros and cons of two of these two industry leaders. Our comparison will look at the following:
The Pros of TPO Roofing
TPO is a budget-friendly roofing solution primarily because it’s inexpensive to manufacture. Roofing contractors can also install TPO roofing systems faster than other “multi-layer” systems, significantly cutting labor costs.
TPO is a highly flexible and durable membrane that can withstand extreme weather and UV exposure. It’s also resistant to punctures, biological growth, dirt build-up, impacts, and water damage.
TPO membranes are predominantly white. As such, they provide a highly reflective and UV-resistant finish capable of reducing roof surface temperatures and cutting interior cooling costs during warmer months.
Easy to Install
TPO is lightweight, so it’s relatively easy to move around on roof surfaces. The installation of wider sheets reduces the number of seams that must be welded, significantly reducing installation time and labor costs.
The Cons of TPO Roofing
As a newer roofing technology, the projected lifespan of TPO is somewhat of an unknown, but most estimates are between 10-25 years. Additionally, there are disparities in the manufacturing process of TPO (from one manufacturer to the next), resulting in some material formulations not lasting much past the 10-year mark.
Excessive heat loads on TPO membranes can eventually cause the seams and flashings to pull apart. It can also cause cracks to form in the membrane’s laminated top layer, making the material more susceptible to damage.
As mentioned above, TPO is a newer single-ply membrane—meaning material formulations are still being perfected. As a result, there exist many lesser-quality variations of TPO in the market.
The Pros of EPDM
EPDM systems are relatively inexpensive compared to other commercial roofing solutions. Ballasted EPDM is the most affordable assembly method for EPDM roofing systems, with fully adhered and mechanically attached being slightly more expensive.
Perhaps the best characteristic of an EPDM roof is its long lifespan. A properly installed and maintained EPDM system can last up to 40 years or more, significantly longer than other single-ply membranes.
Easy to Install
EPDM is a lightweight material manufactured into wide rolls that are quick and easy to install. As a result, the installation time and labor costs associated with EPDM roofing systems are significantly reduced.
Easy to Maintain
Because of the wide rolls, EPDM roof systems yield fewer seams, significantly reducing maintenance and repair costs over the system’s lifespan. EPDM is also easy to repair (or patch).
The manufacturing process of EPDM has a minimal environmental impact, and the membrane is 100% recyclable.
The Cons of EPDM Roofing
As EPDM membranes age, they become more prone to sudden damage (i.e., hail, wind-driven debris, foot traffic, rooftop equipment, etc.).
Shrinkage is when the EDPM membrane constricts and separates (referred to as bridging) around sensitive roof areas such as parapet walls, seams, and penetrations. It occurs gradually over time and is typically the result of poor installation or bad design.
Over time, EPDM roofs tend to become rather unsightly due to the build-up of dirt, dust, and other foreign contaminants. This issue is primarily cosmetic and can be avoided with regular cleaning.
Over time, the adhesives that bond the seams of EPDM roofing systems tend to dry out and weaken. This lack of adhesion can cause tiny openings to form, thus allowing water to enter the roofing assembly. Shrinkage and poor installation can exacerbate this issue.
Recommended Reading: For a more in-depth look at EPDM roofing, click here.
Now that we know the strengths and limitations of TPO and EPDM roofing, let’s see how the two membranes stack up concerning a few key metrics:
TPO and EPDM are similar in cost, but the superior life expectancy of the latter makes it the better investment. But there are several factors to consider when choosing the most cost-effective solution, including climate, weather concerns, building code requirements, roof construction, building aesthetics, warranty requirements, etc.
One of the primary factors to consider when choosing a roofing material is its durability and lifespan. EPDM tends to last longer than TPO. While TPO has become increasingly popular over the last 20 years, it does not have quite the same “proven” track record as EPDM, which has been around for over 60 years.
Regularly scheduled maintenance is highly recommended for both EPDM and TPO roofing systems. Nonetheless, EPDM will likely require more attention over its lifespan due to its adhesively-bonded seams. Also, EPDM membranes have a low resistance to certain solvents, oils, and chemical abrasives.
White TPO membranes offer exceptional thermal reflectivity, significantly reducing cooling costs for buildings in warmer climates. In contrast, black EPDM membranes absorb more of the sun’s heat, which benefits roofs in colder parts of the country. EPDM can also be coated with reflective materials to improve energy efficiency.
Ultimately, determining which single-ply performs best regarding energy efficiency depends on the number of cooling/heating days for a given location.
TPO has a higher resistance to punctures than EPDM. Additionally, TPO seam strength is nearly four times that of an EPDM adhered/taped seam. That said, on average, EPDM roofing membranes are proven to last considerably longer than TPO.
Also, thicker variations of TPO and EPDM membranes typically perform better and last longer.
Keep in mind that the durability and performance of both TPO and EPDM membranes depend on specific environmental factors, proper installation, and routine maintenance.
Both TPO and EPDM come in rolls that are quick and easy to install. Choosing a contractor specializing in one or the other can make a huge difference in the time frame and quality of the installation.
TPO is installed in one of two ways: mechanically attached (with plates and fasteners) or fully adhered (with bonding adhesives). The seams are heat-welded together with specialized equipment and tools.
EPDM can be mechanically fastened, fully adhered, or ballasted. In ballasted EPDM systems, the membrane is loose-laid on roof surfaces and held in place with gravel, river-washed stones, or concrete pavers. The seams are fused with a specialized bonding adhesive and tape.
Choosing between TPO and EPDM roofing ultimately depends on your specific needs and preferences. TPO roofing excels in UV resistance, energy efficiency, and affordability, while EPDM roofing offers durability and flexibility. Consider factors such as your climate, budget, and desired aesthetic when making a decision. Consulting with a roofing professional can provide valuable insights tailored to your unique circumstances, ensuring that you make the best choice for your building's long-term performance and protection.