EPDM vs TPO vs Modified Bitumen: Comparing Flat Roofing Materials for Long Island Commercial Buildings

Choosing the Right Flat Roof for Your Long Island Commercial Building: A Complete Material Comparison

When it comes to commercial buildings on Long Island, selecting the right flat roofing material is a critical decision that impacts both your operational costs and building protection for decades to come. Long Island falls in climate zone 4A, which requires R-20 minimum for most commercial buildings, and the region’s unique coastal climate presents specific challenges that must be considered when evaluating roofing options.

Long Island’s coastal climate presents unique roofing challenges. Nor’easters bring high winds and driving rain, while humid summers can promote mold and algae growth. Winter freeze-thaw cycles can damage shingles and flashing. Understanding how EPDM, TPO, and Modified Bitumen perform in these conditions is essential for making an informed investment.

EPDM: The Proven Performer

EPDM (Ethylene Propylene Diene Monomer) has been the workhorse of commercial flat roofing for over five decades. EPDM is the most popular rubber roofing system and has been in use for over fifty years, giving it the longest track record among flat roofing materials.

Advantages for Long Island Commercial Buildings:

  • This synthetic rubber membrane withstands harsh weather, salt air, and temperature changes, making it ideal for the region’s coastal climate. Known for its resilience, EPDM roofing resists UV radiation and holds up well in areas prone to wind and rain
  • EPDM is a tank in cold weather. Carroll said it won’t crack under extreme temperature swings, making it perfect for climates that swing from sub-zero to triple-digit temperatures
  • EPDM is cheaper than TPO which is good for savings. First it is the least expensive flat roofing system on a per sq. ft. basis. According to Legacy USA, the average cost of an EPDM roof is $4.50 – $5.50 while a TPO roof costs on average $3.50 – $9.50
  • Long Island business owners choose EPDM for its cost-effectiveness and long lifespan of 20-30 years

Considerations:

  • Because of its black color, EPDM heats up quickly in the sun, so you lose any cooling effect
  • EPDM seams are typically joined with adhesives or tapes rather than heat welding. Over time, these seams can become the weakest points in the roofing system, particularly if installation quality is compromised or adhesives degrade

TPO: The Energy-Efficient Choice

TPO (Thermoplastic Polyolefin) has gained significant popularity in recent years, particularly for its energy efficiency benefits. Thermoplastic polyolefin (TPO) has become the standard for modern commercial and residential flat roofs, and for good reason.

Advantages for Long Island Commercial Buildings:

  • Commercial TPO roofing has gained popularity throughout Nassau and Suffolk Counties due to its excellent energy efficiency, chemical resistance, and ability to withstand temperature fluctuations. These thermoplastic membranes provide superior protection against UV radiation while reflecting heat to reduce cooling costs during Long Island’s humid summers
  • TPO is a top pick specifically for its insulating properties and lifespan
  • Because its seams are heat-welded, the entire roof acts as a single, continuous, waterproof sheet. The heat welding also creates a stronger bond than traditional adhesives
  • TPO flat roof systems, with their strong resistance to UV rays and heat, offer a longer lifespan of 20 to 30 years when properly maintained

Considerations:

  • It’s newer than rubber or asphalt, said Carroll, which means quality can vary widely among manufacturers. Compared to EPDM and Modified Bitumen, TPO has a shorter track record in the field
  • While TPO roofing typically comes with a higher price tag than EPDM, the superior durability and energy savings often justify the additional upfront cost. Building owners should consider the total cost of ownership rather than just initial installation expenses
  • TPO is known to shrink, and its rigidity causes stress on seams and flashing

Modified Bitumen: The Traditional Upgrade

Modified Bitumen represents an evolution of traditional built-up roofing, combining asphalt with polymer modifiers to create a more flexible, durable material. This system typically consists of multiple layers, including a base sheet, one or more ply sheets, and a cap sheet with granulated or smooth surface.

Advantages for Long Island Commercial Buildings:

  • Modified bitumen roofing provides Long Island commercial buildings with a durable, weather-resistant solution that handles high foot traffic and severe coastal conditions. Composed of reinforced asphalt and polymers, modified bitumen offers excellent flexibility, adapting well to Long Island’s temperature fluctuations
  • Modified bitumen performs well in cold climates where flexibility matters. The material remains pliable during Long Island’s harsh winters. It’s particularly suitable for buildings requiring exceptional durability and proven performance
  • One of the primary benefits of using a modified bitumen roof is that it comes at a lower installation cost

Considerations:

  • The primary disadvantage of modified bitument is its short lifespan of only 10-15 years. Of all the single-ply, low-sloped roofing materials listed here, it is the shortest-lived
  • Although the gravel spread over a modified bitumen roof is intended to offer hazard and UV protection, that granular surface makes it more difficult to correct drainage issues and detect leaks. Those drainage issues and leaks can persist far longer than they might with a TPO roof
  • Using an open flame torch during installation can be a fire hazard. Mishandled torch use has caused more than a few instances of building burning. The risk here is definitely substantial, and it can be substantial enough that some insurers will not even cover roofers who apply modified bitumen using the open torch method

Making the Right Choice for Your Long Island Property

When selecting between these three materials for your Long Island commercial building, consider these key factors:

Climate Considerations: If you live in the north, he recommends a darker membrane (like EPDM), which can be a benefit as it melts snow faster and reduces a structure’s weight load. On the other hand, if you call one of the southern or southwestern states home, opt for TPO for energy savings in hot, sunny climates. Long Island’s position means you’ll experience both scenarios throughout the year.

Budget and Longevity: EPDM is the most cost-effective option; TPO and Modified Bitumen are slightly higher. TPO and Modified Bitumen typically provide longer lifespans and better storm resistance.

Energy Efficiency: For businesses looking to reduce operational costs, TPO’s reflective surface can reduce cooling costs, an advantage in New Jersey summers – a benefit that applies equally to Long Island’s humid summer climate.

Professional Installation is Critical

Regardless of the membrane selected, professional installation by experienced commercial roofing contractors remains critical for long-term performance. Installation quality determines actual performance versus theoretical capabilities. Our experience reveals installation defects cause 68% of premature failures, far exceeding material deficiencies.

For Long Island commercial property owners, working with an experienced local contractor who understands the region’s specific climate challenges is essential. Companies like Expressway Roofing & Chimney, which has been serving Suffolk and Nassau counties for over 22 years, bring the local expertise necessary to navigate Long Island’s unique coastal conditions and building requirements.

Whether you choose EPDM for its proven durability and cost-effectiveness, TPO for its energy efficiency and modern performance, or Modified Bitumen for its traditional reliability, the key to success lies in professional installation and ongoing maintenance. For expert guidance on Flat Roofing Long Island solutions tailored to your specific building needs, consult with experienced local contractors who understand the unique demands of Long Island’s commercial roofing environment.

Ultimately, the best choice depends on your home’s location and the roof’s job description. And remember: the roof is only as good as the materials and team installing it. By understanding the strengths and limitations of each material and working with qualified professionals, you can ensure your commercial building receives the protection it needs to withstand Long Island’s challenging climate for decades to come.