The EPDM vs. TPO debate

When it comes to roofing systems, architects and building owners are faced with many choices, each with its own set of characteristics. On flat or low slope roofs, two popular single-ply roofing membranes are EPDM and TPO. Let’s delve into the features, uses, advantages and disadvantages of each of these roofing materials, so you can make informed decisions.

Thermoplastic polyolefin (TPO, sometimes also called FPO) roofing membranes have gained popularity in recent years as a modern alternative to traditional roofing materials. There are various brands of TPO membranes on the market that differ widely in formulation and design. Major manufacturers in the USA typically incorporate weft-inserted polyester reinforcements, while European manufacturers tend to use either fiberglass or polyester reinforcement, woven or laid, or a combination of both. In short, each TPO membrane has unique properties such as weldability, mechanical strength (tensile, tear, and puncture resistance), and performance when exposed to heat aging and UV radiation. 

TPO membranes often come in reflective white or light-colored options, helping to reduce heat absorption and contribute to energy efficiency. This can help lower cooling costs in buildings with moderate or no insulation that are located in warmer regions. 

When selecting a TPO membrane, however, long-term performance is a critical factor. Test results for heat and UV aging and thickness over scrim provide a first indication of performance. It is also safer to choose an established manufacturer with a proven formulation and long-standing performance record, without the need for reformulation to address shortfalls such as splitting, polymer erosion, or rapid deterioration. A high-quality TPO roofing system is estimated to have a lifespan of between 20 and 30 years.

In the pursuit of sustainable living and environmentally friendly construction practices, the focus is shifting towards innovative roofing solutions. Flat roofs provide a versatile and expansive canvas allowing for the efficient use of space, particularly in urban settings. This characteristic is particularly beneficial for the incorporation of solar, green and blue roofs. 

Both EPDM and TPO roofing membranes are suitable for these types of application. They are robust yet lightweight, are extremely durable and need very little maintenance. Check, however, that the chosen membrane has achieved good results in the relevant root penetration and heat aging tests.

While both EPDM and TPO roofing systems are relatively easy to install, proper installation requires skilled professionals to ensure a watertight seal. Poor installation can lead to issues such as seam separation and leaks.

EPDM and TPO membranes can be secured in place using different methods, depending on the requirements of the project. They can be fully adhered to the roof deck by means of bonding adhesives, mechanically attached using plates and fasteners, or ballasted with gravel or concrete pavers. In EPDM roofing systems, seams between adjoining membranes are carried out with self-adhesive tapes, while on TPO systems, membranes are heat-welded together. The application is completely flame-free which results in safer working conditions. 

Both membranes are very versatile in their application. They are available in different thicknesses and widths, so the amount of seams can be optimized. They can be used on commercial, industrial, and residential roofing projects, both on new construction and for retrofitting existing roofs. They can be installed onto the existing roofing system, eradicating the need for tearing off, and significantly minimizing construction waste.

In the EPDM vs. TPO roofing membrane debate, architects and building owners must carefully weigh the specific needs of the project against the strengths and weaknesses of each material. EPDM's long-standing reputation for durability and flexibility makes it a solid choice, while TPO's energy-efficient properties on warm climates and ease of installation appeal to those looking for modern solutions.

Ultimately, the decision between EPDM and TPO will depend on factors such as project requirements, building lifespan, environmental considerations, geographical location of the building, local codes and regulations, and budget constraints, to name just a few. 

By understanding the distinctive features of EPDM and TPO, architects and building owners can make informed decisions that align with the goals and specifications of their projects. Close collaboration with roofing professionals is also key to ensuring proper installation and ongoing maintenance, maximizing the longevity and performance of the chosen roofing system.