What Are Flat Roofs Made of: Deciding on the Material  

commercial flat roofing

Commercial properties are investments. Whether your business owns the entire property or you intend to use it for income, a roof with a long lifespan, excellent durability, and offers a lot more based on its property value is necessary. You can always go with your roofing contractor’s suggestion given its industry experience. However, you will save money if you know what are flat roofs made of and the advantages they can give you. Remember, the most expensive choice is not always the best one.

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Things to Consider Before Deciding on Flat Roofing Material


Roofing manufacturers strive to make their roofs durable. Their products, while in average demand, contractors seek out if such materials prove to be excellent investments. Each type of roofing material varies in durability. Its capabilities depend heavily not just on material but in the installation process as well.


Contractors will suggest roofing material from different cost tiers. Discounted variations of strong material will save money. However, it does not guarantee it can deliver the lifespan and durability its superior counterparts can offer. Given that your contractors have worked even with discounted materials in the past, you can trust their recommendations.

To minimize any risk of roofing issues in the future, you need to know what are flat roofs made of, and which materials is your contractor most confident to use to achieve your objectives.

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Even with durable roofing materials, certain situations will shorten their lifespan. For example, EPDM roofs are the most cost-effective flat roofing material. However, their life expectancy is cut short if heavy and sharp tools pierce through the membrane. Inadequate installation of superior EPDM will also affect its lifespan.

Therefore, to increase your roofing material’s lifespan, know what are flat roofs made of, and gauge your contractor’s aptitude for installing each of these different roofing materials.

What Are Flat Roofs Made of: Seven Materials to Choose From

Rubber /EPDM

Contractors will highly recommend ethylene propylene diene monomer (EPDM) roofs. Commonly known as rubber roofs or rubber membranes, it is known for its strength, durability, and cost. Rubber membranes are eco-friendly because all manufacturers use discarded rubber from vehicle wheels, sawdust, and slate dust to create them.

If installed effectively, they give properties a lifespan of over 20-30 years. They can create a flat roof watertight seal that adds insulation, reflects UV rays, and prevents the growth of mold, algae, and other dangerous airborne lifeforms. It costs about $0.80 per square foot.


Thermoplastic Olefin (TPO) is another rubber roofing membrane. By adding polypropylene to EPDM’s base structure, manufacturers create a thicker yet heavier material that introduces EPDM’s advantages and improves its durability and lifespan but at an additional cost.

Compared to EPDM, TPO is fire-retardant and introduces the best property insulation with its airtight seal capability. The roofing material has an average lifespan of 20-30 years. It also costs a bit more at $5-$6 per square foot. Another thing to note is its quality varies between manufacturers given the lack of consensus to its formulation.


The strongest modern material compared to EPDM and TPO, Polyvinyl Chloride (PVC) flat roofing materials withstands heavy materials with an average 350 pounds per inch (PPI) weight-carrying capability. This means it can carry multiple HVAC systems and not tear their membrane. PVC roofing materials have a lifespan of 20-30 years.

Similar to EPDM and TPO, it can create water and airtight seals that guarantee maximum insulation. Its superior layers can reflect UV rays and it is fire retardant. However, most property owners avoid using them because they can cost about $6-$9.5 per square foot.

TPO Roofing System


Metal roofs are not just for warehouses. Flat-roofed commercial properties can take advantage of their lightness and capability. The light material does not require the installation of additional support structures such as joists. Metal roofs are easy to repair with the right tools and sealants.

If properly installed, they can last for more than 30 years and can reach 50 years. Contractors that use special roofing paint enhance their lifespan as the paint protects them from chipping. Metal roofs reflect UV rays, resist fires, and are easy to install.

However, they are quite expensive and noisy during rain and hailstorms. A square foot of metal roof costs about $15-$60.

Tar and Gravel

Traditional hot tar and gravel is the sturdiest yet the heaviest among all the roofing materials in this list. However, the layers of corrosion-resistant material caked together by tar can withstand even the most troubling weather and introduce excellent insulation for commercial properties.

In fact, they are cheaper than metal roofs and PVC membranes costing only about $4 per square foot (depending on the quality and number of layers used). However, upon initial installation, tar and gravel roofs are smelly. And they can only last up to 20-40 years.

Tar and Gravel

Roofing Felt

If you know what are flat roofs made of, then you know that modified bitumen is an excellent and cost-effective roofing material as well. They have an average lifespan of 20 years and costs only $0.38 per square foot.

While incapable of introducing airtight seals, roofing felt and modified bitumen resists water leaks and lasts through any testing weather. As long as the roof has excellent rainwater management through its gutter system, the roofing material can last up to 20 years.


Mastic asphalt can last up to 50 years, but it is heavy. It requires you to modify your roofing joists. However, this one-time investment on infrastructure development gives you the durability and lifespan by using material contractors also use to create car parks, structural decks, roads, and bridges.

Asphalt is expensive than other materials in this list at $2.50-$4 per square foot. However, it is easy to repair. Contractors can mold asphalt into different shapes, such as patches to cracked surfaces.


By knowing what are flat roofs made of, you can save money and invest on a roof that can last long and withstand the test of time. However, take note that its lifespan depends on its installation. It would be best to contact professional roofing companies to help you construct your roofs and guarantee its long life.