What’s the Best Material for a Flat Roof?

In this quick guide, we go over some flat roofing materials together and find the perfect fit for your roof.
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Reviewed by JC Sanjuan — General and roofing contractor with over a decade of experience in residential and commercial construction. He specializes in project management, quality workmanship, client satisfaction, and solving roofing challenges.

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Choosing the right material for your flat roof can feel like a maze. With so many options out there, it’s easy to get lost in technical jargon and marketing pitches. But here’s the thing: your roof is your home’s shield against rain, sun, and everything in between, so picking the right material is key. Whether you’re fixing up an old roof or starting from scratch, each material comes with its own set of pros and cons, from how long it’ll last to how much it’ll cost you.

In this quick guide, we’ll break down the top choices in plain English, helping you figure out which one ticks all your boxes for durability, budget, and looks. Let’s go over some flat roofing materials together and find the perfect fit for your roof.

Types of Flat Roofs

Choosing the best material for a flat roof depends on several factors, including your budget, climate, and specific needs for durability and maintenance. Here’s a breakdown of some popular flat roof materials to help you decide:

EPDM (Ethylene Propylene Diene Monomer)

Roof worker installing EDPM roofing membrane to flat roof for a commercial building
Credit epdmroofsorg

EPDM is a synthetic rubber roofing membrane known for its durability and versatility. It’s resistant to UV rays, ozone, and weathering, making it a popular choice for flat roofs. It’s relatively easy to install and repair, and it has a long lifespan of up to 30 years with proper maintenance.

  • When to Consider: If you’re looking for a cost-effective, durable solution that withstands various weather conditions without breaking the bank.
  • Ideal For: Homeowners in areas with fluctuating temperatures and those seeking an eco-friendly option, as EPDM is recyclable.

TPO (Thermoplastic Polyolefin)

Roofers installing TPO roofing material on a flat commercial building roof
Credit: GAF

TPO is another synthetic roofing material that has gained popularity due to its reflective properties, which can help reduce cooling costs. It’s resistant to UV light, punctures, and tears. TPO roofs are also known for their heat-welded seams, which create a strong bond, reducing the risk of leaks. The expected lifespan of a TPO roof is around 20 to 30 years.

  • When to Consider: If energy efficiency is a priority. Its reflective surface can help reduce cooling costs in warmer climates.
  • Ideal For: Those in sunny regions or anyone looking to cut down on energy bills. Also great for roofs with more equipment since its puncture and tear resistance is excellent.

PVC (Polyvinyl Chloride)

Photo a commercial PVC roofing material
Credit: Centimark.com

PVC roofing is similar to TPO in terms of benefits and installation. It’s highly resistant to chemical exposure, fire, and water, making it a strong option for flat roofs. PVC roofs are also reflective and can help lower energy costs. The lifespan of a PVC roof can range from 20 to 30 years.

  • When to Consider: If you require a strong, waterproof roof that can resist chemicals and fire. It’s also suitable for roofs that need to support heavier loads.
  • Ideal For: Properties in areas prone to chemical exposure or if the roof will host heavy equipment. Also, good for those seeking energy efficiency.

Modified Bitumen

Roofers installing Certainteed's Flinlastic Modified Bitumen Products
Credit: CJroofing.com

This is an evolution of the old built-up roofing (BUR) systems. A modified bitumen roof consists of layers of bitumen (asphalt) that are modified with polymers to improve elasticity and durability, and then combined with fiberglass or polyester fiber matting. These roofs are known for their toughness and are particularly good in areas with heavy foot traffic. With proper installation and maintenance, modified bitumen roofs can last 20 years or more.

  • When to Consider: For those seeking a balance between traditional and modern roofing solutions, offering durability and ease of repair.
  • Ideal For: Urban homes or buildings where the roof may be used as a leisure area, thanks to its resistance to foot traffic.

Built-Up Roofing (BUR)

Close up view of a multi layer built up roof system on a commercial building

The traditional hot-tar-and-gravel roof consists of multiple layers of bitumen and reinforcing fabrics. This creates a finished membrane that is thick and durable. BUR is known for its longevity, waterproofing abilities, and resistance to foot traffic. However, it’s heavy and requires a strong supporting structure. The lifespan of a BUR system can exceed 20 years, depending on the materials used and the quality of the installation.

  • When to Consider: If you’re looking for a time-tested, durable option and don’t mind the installation’s weight and complexity.
  • Ideal For: Older buildings that can support the weight or any roof where durability and longevity are top priorities.

Spray Polyurethane Foam (SPF)

Roofer spraying Spray Polyurethane Foam over flat roof commercial application
Credit AmericanWeatherstarcom

SPF is a spray-applied foam that forms a continuous, seamless layer over existing roof structures. It offers excellent insulation properties and is highly resistant to water. SPF can also be applied to various substrates, making it a versatile option for flat roofs. With proper maintenance, an SPF roof can last over 50 years.

  • When to Consider: For maximizing insulation and sealing capabilities, especially in climates with significant temperature swings.
  • Ideal For: Eco-conscious homeowners or those in extreme weather conditions who want to significantly reduce their heating and cooling costs. Also great for roofs with irregular shapes or numerous protrusions.

Key Considerations:

  • Budget: Some materials, like PVC and TPO, may have higher upfront costs but offer savings in maintenance and energy efficiency.
  • Climate: Materials like SPF and EPDM are better suited to withstand extreme temperatures, while TPO and PVC can help cool your home in hot climates.
  • Usage: If your roof will see a lot of foot traffic, consider more durable options like Modified Bitumen or BUR.
  • Longevity and Maintenance: Consider how long you plan to stay in your home and how much maintenance you’re willing to perform. Some materials require more upkeep than others.

Bottom Line

Each material has its advantages and potential drawbacks. The “best” choice depends on your specific requirements, including climate, building usage, energy efficiency needs, and budget. Consulting with a roofing professional who can assess your specific situation and provide personalized advice is always a good idea.

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