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Flat Roof Material Options

You can achieve proper flat roof installation with different approaches, but the most important thing is to use suitable materials. This article will review the materials required for flat roof installation, so keep reading.

Roofing Materials For Flat Roof

People install different types of flat roofs on their properties, and each of these roofing systems has its individual needs. This includes the materials used for their installation, each of which comes with its advantages and disadvantages. Most roofing contractors use single-ply roofing materials for flat roof repair and installation.

Some roofing material options include:

  • Built-up roofs (BUR)
  • TPO Vinyl
  • Modified Bitumen Torch Down
  • Ethylene Propylene Diene Monomer (EPDM Rubber)

Most Common Flat Roofing Materials

Modified Bitumen and EPDM are the most popular roofing materials used by most contractors. Built-up roofs are among the oldest roofing materials that people use, and they are made of gravel and hot tar. BUR roofs are attractive and also resistant to fire. Another reason people like to use them is that they are affordable. However, tar and gravel are heavy, and the installation of this type of material is complicated and messy.

Another issue with this type of roofing is its ability to clog gutters, which is why it's not an ideal option for occupied buildings. TPO vinyl is a relatively new material that people use for flat roofs because it's an energy-efficient option. However, finding a contractor that can handle this type of roofing need is not easy. It is also the most expensive roofing option available.

Modified bitumen is another option, and there are two different types of modified bitumen roofing materials. Peel and stick and torch down are the two different types. The peel and stick option has a bright colour and a mineral surface, which makes it an excellent choice for cutting down energy bills. Another impressive thing about the peel and stick option is the price, which is considered to be mid-range. The second type of modified bitumen is the torch down option, and this type requires heat welding for installation.

Characteristics Of Flat Roofs

A key thing to note about flat roofs is that pooling water is among their significant disadvantages. However, if you plan to install a flat roof on your property, then you should consider sunlight when selecting the type of roofing material to install on your flat roof.

Another thing to note is that flat roofs usually receive more sunlight, unlike pitched roofs. Ultraviolet lights or direct sunlight can degrade the roofing materials, triggering faster disintegration. However, ceramic and stone roofing materials are the only materials that are resistant to UV light. It's worth mentioning that the EPDM rubber roof lacks ceramic granules, while modified bitumen contains them.

EPDM Rubber Vs. Modified Bitumen

EPDM Rubber

  • It is more expensive than built-up roofs (BUR) or modified bitumen materials.
  • Unable to withstand heavy foot traffic.
  • A good option for people in temperate regions.
  • Not resistant to UV light, and you can't coat it against UV light.

One of the main disadvantages of the EPDM rubber roofing material is that the seams for the single-ply rubber membrane are only glued with the aid of an adhesive, which is likely to come in contact with cement. Also, this has a meagre resistance to heat. As mentioned earlier, flat roofs come in direct contact with sunlight, which will only shorten the roof's lifespan since it's glued with an adhesive. Despite that, EPDM rubber remains an easy and affordable option to fix.

Another thing to note about EPDM rubber is that it's thin, which increases its chances of getting damaged easily, especially from falling debris or foot traffic. In cases where your property has an air conditioner that needs repair or replacement, your flat roof will be at a higher risk of getting damaged, primarily if the contractor accesses the component from the flat roof.

Coating a flat roof with single-ply EPDM rubber will make it last between 10 to 15 years. It's worth mentioning that the initial design of EPDM rubber wasn't done for commercial buildings, but after many years, they became widely accepted for use on commercial flat roofs.

Modified Bitumen

  • The material is considered to be mid-priced.
  • It's more than one centimeter thick.
  • Does not get damaged by foot traffic, even during maintenance.
  • You can paint it.
  • UV light resistance because it has ceramic granules embedded in it.
  • Seams are heat welded, which keeps them firmly attached.
  • Does not require much preparation before installation.

Benefits Of Modified Bitumen Roofing

You might be wondering why modified bitumen is a better roofing material and a more preferred option for flat roofs. Below are some reasons to pick modified bitumen over EPDM rubber:


People still use EPDM rubber, but the main issue with this option is that glue is used to hold the seams together. That's not the case with modified bitumen, as the seams are heat welded. This implies that they cannot break easily from sunlight and heat degradation.

Another thing to note is that modified bitumen is a sturdier and thicker roofing material, and as such, it's a lot easier to repair and maintain, unlike EPDM rubber. Unlike other flat roofing systems, modified bitumen has the most extended lifespan and requires very little maintenance.

Basically, modified bitumen is designed to withstand a higher degree of foot traffic. This is an essential factor because flat roofing systems are the main access routes for the maintenance of vital components of the house, like the air conditioning units.

Another point of consideration is the fact that flat roofs collect snow. Therefore, if you have a flat roof on your property, you'll need to shovel the roof regularly, and for that purpose, modified bitumen is the best option.

No shrinking

As time passes, the roofing system rubber membranes and roof coatings tend to shrink due to different factors. When this occurs, it causes the roof materials to pull away and detach from the flashings and wall, thereby creating an access point for pests and water to go under the roof structure. You can avoid this issue with modified bitumen because shrinking is not a concern with this type of material.

Little preparation required

EPDM rubber is installed after a significant level of preparation, which is not the case with modified bitumen. Modified bitumen only requires little upfront preparation and cleaning. However, one thing to note is that modified bitumen is still a new roofing material. Not every roofing contractor will be familiar with the material, including how to install it.

Modified bitumen roofs are generally considered to last for at least 20 years, even without regular maintenance. This is what makes it an excellent material for residential and commercial roofing. In terms of the cost, it is more economical than EPDM rubber roofing materials.

Benefits Of EPDM Rubber Roofing

From everything above, you might want to think that modified bitumen should be the most preferred roofing material at all times. However, there are cases where EPDM is a better option. For example, if you live in areas with temperate climates, particularly in which there are no extreme swings in temperature, an EPDM roof is a good option.

Another scenario is where your flat roof is shaded. In such an instance, the EPDM rubber roof will last longer because it's better shielded from UV light. However, the EPDM rubber roof is likely to shrink in places with extreme weather conditions. Therefore, modified bitumen is a better option for such areas.

When Your Flat Roof Needs To Be Replaced

There are many signs to look out for to help you know whether your roof needs a replacement or not, even if its metal roofing. This also applies to a flat roofing system. In fact, flat roofs have a higher susceptibility to leaks and other issues compared to pitched roofs.

One of the major problems associated with flat roofing systems is pooling water. If your flat roof has a pool of water and it stays there for more than 48 hours, it will likely affect the structural integrity of your roof and also compromise your building. If this happens, you may need to get a replacement as soon as possible.

If you don't install a new rubber membrane, it will cause the water to go into the walls of your property, and this can cause even more severe problems. Here's an overview of some of the issues your flat roof is likely to face:

Pooling water

As mentioned earlier, pooling water is one of the most common problems that people with flat roofs are likely to face. If the pool of water lasts more than 48 hours, you'll need to fix it quickly. For this, you'll need to get an experienced roofing contractor to install slippers like foam under the rubber roof membrane. This will give the roofing system a pitch, reduce the chance of having an excess pool of water in your flat roof, and extend the roofing system's lifespan.

Pulled apart membrane or tears in the rubber membrane

As mentioned earlier, pieces of single-ply material are usually included in flat roofs. This can either be welded or glued together. If you observe any signs of shrinkage or tears, it's best to get the roofs repaired immediately. Even if there's a slight tear in the roof, you should get it fixed quickly. However, if the rip is significant, you may need a replacement.

One thing to note is that roofing materials made from gravel or hot tar are more challenging to repair. Therefore, whenever you observe any of the signs above, the best thing is to contact your roofing contractor immediately.

Other Flat Roof Materials

We have focused more on EPDM rubber and modified bitumen above, but those are not the only flat roof materials available. There are many other options you should know, and they include the following:

Built-Up Roofs (BUR)

These are one of the earlier roofing materials you should know, and they are the most common options for commercial and industrial roofing systems. These roofs are comprised of different layers of bitumen and ply sheets. This is in addition to the top layer of aggregate finishing, like slag, mineral granules, or rocks.

The general lifespan of most BUR roofs is around 15 to 30 years. They offer waterproofing and UV protection and require very little maintenance. However, they are expensive and more challenging to install.

Single-Ply (TPO, PVC)

Single-ply membranes like TPO and PVC are rapidly becoming the most common options used in many commercial flat roofs. Both materials are quite identical, and they share a few similarities. They are both white, thermoplastic, heat-welded roofing systems.

TPO is a flexible material and relatively easy to install and maintain. It's also less expensive. However, PVC is a more durable option and resists fire and water. It's also more costly than TPO.

Spray Polyurethane Foam

This is also not a popular option compared to the other options mentioned earlier. However, it's worth noting that it's one of the most effective flat roofing systems you'll find on the market today. The critical thing to note about this type of roof is that it's made from a combination of plural components, closed-cell, and spray polyurethane foam. All of this is together with a protective elastomeric top-coating.

When maintained properly, this flat roofing material can last up to 50 years. They are an excellent option for providing an insulation barrier suitable for flat roofs. They also offer better thermal resistance and energy efficiency. Another impressive thing is that spray foam is generally strong and helps increase the structural integrity of buildings, primarily commercial buildings.

Deciding To Repair Or Replace A Flat Roof

The roof of your dwelling is the most essential part of every building; you shouldn't take this component lightly. You can keep pests and water out of your home with a new roof. It will also help to improve your home's resale value and increase its appeal. In some cases, it's better to repair the roof rather than get a replacement for the roof.

Examples of these cases include times during which the materials of your roof are still relatively new, but there are a few damages. Simply repairing the damage is a good choice. However, there are cases where the roof has simply exceeded its service life. In this case, the repair is likely to cost you more than 20% of the price of getting a new roof.

If that's the case, then it's best you install a new flat roof on your property. This will give you definite peace of mind and the assurance that it will last you between 15 to 20 years. Another benefit of getting a new roof is that it will improve your property's resale value and appeal.

With all the flat roofing materials that we have mentioned above, you might start to wonder which is best for your property. The critical thing you should note is that all these materials are designed differently, each having their strengths and weaknesses. To fully determine which is the best flat roofing material for your property, it's advisable to contact a flat roofing contractor to give you professional advice.

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