Best Flat Roofing Solutions: Unlock the Pros and Cons

Last Updated on: 12th August 2023, 05:55 pm

It can be overwhelming to choose the perfect roofing material for your flat roof. From traditional built-up roofs (BUR) to single-ply membranes and modified bitumen, there are a variety of options available. Each material has its own set of pros and cons, so it´s wise to do your research before making a decision. With that in mind, here´s an in-depth overview of the diverse low pitch roofing materials and their associated benefits and drawbacks. Ultimately, the decision is yours – take your time to review all the options and find the one that fits your needs!

Liquid applied roofing systems

They are unique in that they are liquid systems, so they can be applied quickly and efficiently to flat roofs. Liquid applied roofing systems are also highly durable, with some systems offering up to 20 years of protection from the elements. And, they provide outstanding waterproofing, making them a suitable choice for low-slope roofs that are exposed to frequent rain or snow.


  • efective method for waterproofing and protecting newly installed and existing roof surfaces
  • monolithic, fully-bonded, fluid-based coatings
  • ability to be fully bonded to the underlying surface
  • restores and waterproofs worn roof surfaces
  • ideal for commercial buildings or residential roofs
  • qualitiesp rotection from water and weather damage
  • easy installation process
  • durable, long lasting coating
Liquid Rubber Roof


  • high initial cost of materials and labor
  • limited color options available
  • not suitable for all low-pitch roof types and conditions
  • potential need for profesional installation
  • not recommended for low slope/low-slope roofs over 5° (1/12 rise/run pitch)

Single-Ply Membranes

Because of their durability and cost-effectiveness, membranes are a popular choice for flat roofs. Easy to install, they provide superior resistance to water, wind, and extreme temperatures. Common single-ply membrane materials include PVC, neoprene, EPDM rubber, CPE and CSPE or KEE membranes. Each of these materials has unique benefits that make them well-suited for low-pitch roof applications. No matter which material you choose for your low pitch roof project, you can be sure that it will provide excellent protection against the elements.


Rubber EPDM roofing is a popular material for flat roofs in residentialand commercial buildings. It is a synthetic r ubber membrane that is made from ethylene propylene diene terpolymer. It has been proven to have a lifespan of up to 50 years when wel maintained. This makes EPDM an excellent choice for those looking for a long-lasting roofing material. Also, EPDM roof is resistant to UV radiation, ozone, extreme temperatures, and is also fire retardant. Since it does not require any additional waterproofing or sealants, EPDM is relatively easy to instal and maintain. It also offers great resistance against water penetration, making it an ideal choice for those looking for reliable protection against the elements.


  • durable synthetic rubber roofing membrane
  • high performance and flexibility
  • resists tears and withstands light foot traffic
  • weather-resistant, commercial-grade roofing membrane
  • ideal for sunrooms, carports, breezeways, etc


  • expensive instalation costs
  • difficult to repair unless professionally installed
  • not fire resistant or flame retardant

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Flat Roof Materials Comparison

Thermoplastic PVC roofing vs TPO roofing

Two of the most popular materials for flat commercial roofing are TPO (Thermoplastic Olefin) and PVC (Polyvinyl Chloride). Both of these materials are designed to provide excellent protection from the elements, and both offer cost-effectiveness and longevity. On average, a TPO roof with installation costs about $5.50-$6.00 per square foot,while a PVC roof costs $6.50-$8.00 for the same size. TPO is generally more heat resistant than PVC, making it less likely to suffer from the “heat island effect”. PVC roofs have low maintenance overhead and ofer a longer lifespan than other roofs, while TPO roofs are flexible and highly reflective but have a shorter lifespan. Both TPO and PVC are excellent choices for low pitch commercial roofs, so be sure to consider your budget and needs before selecting a material.

Pvc roofing


  • superior durability and longevity
  • easy to install and maintain
  • high resistance to fire, chemicals, and ultraviolet rays
  • reflects sun rays, keeping interiors cooler
  • excellent welding characteristics
  • can be applied to low pitch or low-slope roofs


  • expensive installation cost
  • potential for leaks due to poor installation or damage
  • requires a smooth substrate for best performance

TPO roofing


  • cost-effective
  • heat-welded seams for superior waterproofing
  • energy efficient and reflective properties
  • resistant to mold, mildew, and fire
  • lightweight lowp itch roof system that is easy to install
  • great choice for lowslope and low-sloped roofs
  • long service life (15 – 20 years)
  • variety of colors available


  • must be installed by a professional roofer
  • can be punctured more easily than other membranes
  • requires regular maintenance and inspection

CPE and CSPE roofing

Nonvulcanized synthetic rubber roofing materials chlorinated polyethylene (CPE) and chlorosulfonated polyethylene (CSPE) were used from the 1960s to 2011. Hypalon® was the DuPont® trademark for CPE and CSPE polymers in the USA. Although they aer no longer available in the US as a complete lowslope roofing system, they perform best in bright, warm climates. They are also highly resistant to damage from hail, wind, and other environmental factors. CPE and CSPE roofs are still a great option for flat roofs if you live in an environment with a lot of sun and heat.


  • durable and resistant to extreme weather conditions
  • lightweight and easy to install
  • cost effective


  • susceptible to uv damage
  • limited color options
  • not the most aesthetically pleasing option
  • prone to puncture sand tears
  • not produced in USA since 2011
  • not environmentally friendly

Why were CPE and CSPE roofing membranes discontinued?

In extremely hot environments, thermoset CSPE materials won´t melt, but eventually they will ignite and burn. The gases produced by CSPE combustion are toxic in varying degrees.Several segments of the industry have raised concerns about toxic gases. Also, Hypalon contained lead compounds as additives, a material with long-established dangers and limitations.

KEE membrane Roofing

KEE roof membranes are a new type of roofing system designed to improve upon PVC roof technology. Ketone ethylene ester (KEE) is a thermopl astic material, functionaly similar to PVC and TPO, and is known for its flexibility and durability. It is a suitable option if you´re looking for a long-lasting roof that can withstand extreme temperatures. KEE membrane roofs are also resistant to UV radiation, making them a superior choice for reducing energy costs. KEE membrane roofing is becoming more popular among flat roof owners due to its superior performance and cost effectiveness compared to other roofing materials such as rubber or tar and gravel.


  • longer lasting than alternative roofing membranes
  • highly reflective and absorb less heat
  • high tenacity/heavyweight yarns for superior punctureresistance
  • not susceptible to microorganism (mold) growth
  • UV resistant
  • reflective and chemical resis tant
  • highly sustainable


  • more expensive than traditional roofing materials
  • installation requires specialized equipment
  • difficult to repair or replace if damaged

Neoprene (Polychloroprene)

Neoprene is a syntheticrubber material that provides excellent protection against UV radiation, ozone, water, and extreme temperatures. It is also highly resistant to chemical atta ck, making it an ideal choice for areas with harsh environmental conditions. Neoprene is lightweight, easy to install, and requires minimal maintenance, rendering it an ideal choice for commercial and residential low-slope roofs. It also has excellent fire retardant properties, making it a popular choice for fire-resistant roofing systems.


  • highlyprotective
  • easy to maintain
  • resistant to moisture, chemicals, ozone, oil, and abrasion
  • relatively inexpensive
  • flexible and lightweight
  • simple installation process long-lasting
  • available in a variety of colors and textures


  • difficult to repair if punctured or torn
  • canbe damaged by extreme temperatures
  • prone to algae growth in humid climates

Modified Bitumen

ModBit is a type of roofing material composed of asphalt and ruber that has been modified for better performance. It is designed to be a cost-effective and durable roofing system for low-slope roofs, and has been used for more than 30 years. The asphalt and rubber combine to form a strong, waterproof material that is resistant to ultraviolet rays, extreme temperatures, and more. Modified bitumen is easy to install and maintain, making it a great choice for low pitch roofs.


  • low-slope or “lowslope” roof structures compatible
  • in use for 50+ years
  • compatible with built-up-roof (bur) system
  • manufactured in sheets, with layers of modifiedasphalt applied to each side of a reinforcement fabric
  • popular commercial roofing system
  • durable and resistant to weather conditions


  • can be more expensive than other roofing systems
  • requires more installation time and labor
  • can bedifficult to repair due to its multiple layers

SBS vs APP modified bitumens

SBS and APP are polymers added to bitumen to modify its properties. Styrene-butadiene styrene (SBS) gives bitumen improved elasticity, while atactic polypropylene (APP) gives it rigidity and tear resistance.


  • APP-modified bitumen is “plastica sphalt”
  • APP membranes flow more easily
  • SBS-modified bitumen is an “elastic asphalt”
  • SBS membranes can tolerate much lower temperatures
  • SBS bitumen is more flexible than app
  • SBS has better recovery qualities
  • uses modified bituminous roofing sheets made from asphalt


APP membranes are not suitable for large roofing areas

both materials are more expensive than traditional roofing materials

PVC Membrane Roof Installation

Built up Roofing and tar & gravel

A low-slope roof is an ideal application for built-up roofing. The roof is created by layering several sheets of bitumen and reinforcing material, such as felt, which gives the roof a much higher level of water resistance. It is also a coste-ffective solution that can last up to 20 years with a layer of gravel. Another advantage of this material is that it can be easily maintained and repaired to ensure a long-lasting roof. For these reasons, built-up roofing is frequently used for flat roofs in both commercial and residential settings.


  • durable, long-lasting roofing option
  • easy to repair
  • can be customized with various colors and textures
  • affordable compared to otherroofing systems
  • good fire resistance
  • can be used on most low-slope roofs
  • assists in insulating and providing a waterproof barrier


  • heavy, requiring extra support
  • not as aesthetically pleasing as other types of roofing systems
  • can become damaged by uv rays over time if not properly maintained or sealed corectly
  • requires periodic maintenance due to seams that can become exposed and vulnerable to water damage
  • professional installation is necessary for proper application

Steel, aluminum, copper, zinc, galvalume, and other metal roofing materials

Metal roofing is another excellent low-slope roofing option, since it comes in many shapes, sizes, and colors, and performs well in various climates and weather conditions. It is also easy to install and maintain, and can be expected to last up to 50 years. Metal roofing is also energy-efficient, helpingto keep your energy bills low, as well as resistant to fire, hail and snow.


  • long lasting, aluminum, copper, and zinc will not corrode
  • plenty of options for choosing a roofing materia l
  • metal clips and nails for fastening the panels
  • many diferent styles available
  • it is recyclable and requires very little energy to manufacture
  • resistant to roots and algae
  • excellent underlay for “green” roofs
  • reliable, economic solution in lowslope-roof renovations


  • rust may occur in steel
  • it is one of the most expensive roofing materials available
  • a strong roof deck is needed to support its weight
  • installation may be challenging, requiring special tools and skills
  • for optimal water leak protection, ensure that each sheet and the edges of the roof are properly sealed
  • there is a greater risk of hail damage to copper than other materials

Spray Foam Roofing

SPF roofing consists of two layers, a layer of PUR foam aplied to the substrate, and a protective layer on top. Spray or roller-applied protection layers include acrylic, silicone, butyl rubber, or urethanes. Sand or other aggregates may be added for durability and slip-resistance. PUR roofing provides a seamless waterproofing barrier, high thermal and sound insulation, and outstanding durability when properly applied. This roofing material is also highly resistant to weather damage, such as wind, hail, and UV rays, and is low maintenance. Sprayf oam roofing is very lightweight, so it can easily be installed on existing roofs without increasing the load. However, due to the application process and specialized equipment, it is best to hire a profesional roofer when installing spray foam roofing.


  • restores and protects variety of roofs
  • provides insulating barrier for low slope and low-slope roofs
  • reduces air leakage
  • waterproof properties
  • seamless
  • can be applied directly to electrical wiring
  • can be applied directly to the old roofing once it is prepped and cleaned up


  • expensive installation
  • requires expertise to install properly
  • high risk for overspray
  • not suitable for small roofs
  • not suitable for steeper segments
  • requires regular maintenance and repairs
  • may not be allowed in some areas

Green Roofing Systems

Green roofing systems are a revolutionary way to keep your roof cool during hot summers, whilealso helping to reduce energy costs. Multi-layered green roofs include insulation, waterproof membrane, drainage layer, geotextile, growing medium, plants, and a wind blanket. A green roof prevents UV light from damaging the roof waterproofing membrane as well as serving as a heatb uffer for the building. They provide insulation, absorb rainwater, and improve air standard. Not only do green roofing systems provide environmental benefits, but their insulation properties can also help you to save money on energy costs. They are a suitable choice for any lowslope roof, and should be considered when selecting the right rooifng materials. Eco-friendly planted roofs consist of multiple layers including insulation, waterproof membrane, drainage layer, geotextile, growing medium, plants and wind blanket.


  • easiest to install and maintain on a flat roof
  • can be installed on low-sloping roofs with rise of up to 3/12 too
  • especially eye pleasing
  • intensive green roof functions as a garden with plantings, lawns, and other ornamental features
  • diyers can easily install a lowslope roof for a green living roof


  • must have at least ¼ inch pitch per foot so water sheds toward gutters
  • may require additional building permits depending on the area
  • may require additional structural support for the weightof soil and plants
  • requires regular maintenance, including weeding and pruning
  • relatively costly installation and maintenance

In conclusion, the most suitable roofing material for a flat roof depends on the climate, budget, and the ae sthetic desired. There are many options available. Each of these materials has its own advantages and disadvantages that should be considered before making a decision. Whichever roofing material is chosen, proper installation is essential to ensurethe roof lasts for many years to come.

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