A Row Home Flat Roof Installation Washington DC

10 Types of Low Slope and Flat Roof Materials

Flat roofs and low slope roofs are roofing systems with a pitch of 10 degrees or less. These roofs are popular for both commercial and residential buildings across many regions. They’re especially common in urban areas like Washington, DC, where space is limited, and the types of homes, such as row homes, lend themselves to these types of roofs.

Flat roofs are preferred for their modern design, affordability, and faster installation. They are commonly found on commercial buildings, warehouses, apartment complexes, and even residential properties. In Washington, DC, their ease of upkeep and suitability for densely built environments make them a popular choice.

Choosing the right material is crucial to the performance and longevity of your flat roof. You’ll want to consider factors such as cost, resistance to weather, and energy efficiency, maintenance frequency, and lifespan.

This article will explore flat roofing materials, including material composition, lifespan, and cost. We’ll compare common flat roofing materials such as TPO, EPDM (rubber), PVC, BUR, Modified Bitumen, and more. You’ll also learn about the advantages and disadvantages of these systems, installation requirements, and repair considerations so you can make an informed choice based on what best suits your property’s needs.

Flat Roof Materials

To help distinguish flat roofing materials we’ll break them into three main types:

  • Single Ply, such as TPO, PVC, and EPDM rubber roofing material.
  • Multi-Ply, such as Built Up Roof (BUR) systems and Modified Bitumen.
  • Other flat roof materials, such as metal, green roofs, and roll roofing.

Single Ply Roofing

Single ply is often chosen for its flexibility, durability, and efficiency. Below, we’ll break down the three main types of single-ply roofing materials: EPDM, TPO, and PVC.

EPDM Roofing (Rubber)

Material Composition and Characteristics
EPDM, commonly known as rubber roofing, is made from a synthetic material resembling natural rubber. It comes in large rolls and is easy to work with due to its flexibility. EPDM typically has a smooth and durable black surface, though lighter options are also available.

Typical Lifespan
Generally, EPDM rubber roofs last around 25 to 30 years with proper care, giving them a reasonable lifespan compared to other flat roof materials.

Cost
Compared to other flat roof materials, EPDM is one of the more affordable options. Installation costs are typically lower as it’s easy to roll out and glue down. However, black EPDM can absorb more heat, which may increase energy costs in warmer climates. You may save on flat roof replacement costs because the material is budget-friendly upfront.

Advantages and Disadvantages
Advantages include its flexibility and ability to withstand extreme weather and provide UV protection. On the downside, it can be more prone to punctures and may require patchwork repairs. It can also be less energy-efficient than other flat roof options.

What Types of Structures Might Use This Material?
EPDM is commonly used on commercial flat roofs, especially ones where cost is a priority. It also works on residential flat roofs that aren’t concerned with reflecting heat, like in cooler regions, or on a garage.

Installation Requirements
EPDM installation is relatively hassle-free. It can be fully adhered, ballasted, or mechanically fastened. Rolls are typically large, so seams are minimal, which can increase the efficiency of the installation.

Climate and Regional Considerations
EPDM performs well in all climates; white EPDM suits hot regions better, while black is more suitable for cold regions. The material handles temperature swings without cracking. In warm climates, the extra heat absorption might not make it the most energy efficient choice.

Maintenance and Repair Considerations
EPDM rubber roof repair is generally not difficult. Just keep an eye out for punctures and damage from sharp objects; this is more likely to happen the more often people are trafficking the roof. Rubber roof coatings can extend its lifespan and help maintain the material. Any debris or dirt on the roof will be more visible if you have a white EPDM roof.

Energy Efficiency
EPDM systems that are black offers some insulation but reflective qualities in hotter climate, making them a better choice for cooler areas. For warmer areas, white EPDM is much better at reflecting heat.

TPO Roofing

Material Composition and Characteristics
TPO roofing is a blend of plastic and rubber. It usually comes in white or light colors, giving it a reflective surface. The material is flexible and durable, making it a good membrane roof option.

Typical Lifespan
With proper care, TPO roofs can last 20 to 25 years. They’re slightly less long-lived compared to EPDM rubber roofs, but their energy efficiency gives them an edge in some climates.

Cost
TPO roofing typically comes at a moderate price point. While it may not be as cheap as EPDM, it offers better energy savings, especially in warm regions. Installation costs are competitive, and over time, savings on cooling bills can add up.

Advantages and Disadvantages
TPO roofs are energy-efficient, highly resistant to UV rays, and reflect heat, making them great for warmer climates. They also generally have strong heat-welded seams. However, some earlier formulations of TPO have raised concerns regarding material durability.

What Types of Structures Might Use This Material?
TPO roofing material is ideal for both commercial and residential buildings, particularly in areas that experience hot weather. It’s also a popular choice for buildings where energy efficiency is high on the list of priorities.

Installation Requirements
Installation can be fully adhered, ballasted, or mechanically fastened. The seams are heat-welded, which creates a strong, water-tight bond, but it’s extremely important to hire professionals familiar with TPO roofing installation.

Climate and Regional Considerations
TPO excels in hot, sunny climates thanks to its reflectiveness. Its ability to keep buildings cooler makes it perfect for regions with higher temperatures.

Maintenance and Repair Considerations
TPO roofs are durable and resistant to most kinds of damage. Frequent inspections will help, but it doesn’t require as many repairs as older systems like Built up Roofing (BUR). Repairs are likely to need professional heat welding, which required specialized professionals.

Energy Efficiency
Highly reflective surfaces make TPO more energy-efficient than many other flat roofing materials which can help save on cooling costs over the long term.

PVC Roofing

Material Composition and Characteristics
PVC roofing is made from polyvinyl chloride (a plastic polymer), and is essentially thick plastic with internal reinforcement that is flexible but tough. It’s usually bright white, which makes it a reflective and energy-efficient option.

Typical Lifespan
PVC roofing has a lifespan ranging from 20 to 30 years, making it dependable for longevity. Its durability outpaces that of many other flat roof materials.

Cost
PVC roofing tends to be one of the pricier options for single-ply membranes when compared to EPDM and TPO roofs. Installation can generally cost more due to the need for specialized professionals. However, the high cost is often offset by long-term durability and energy savings in warmer climates.

Advantages and Disadvantages
PVC excels in energy efficiency, puncture resistance, and chemical resistance. On the downside, it’s more expensive and may require specialized installation labor and cost more to repair.

What Types of Structures Might Use This Material?
PVC is favored in commercial settings, especially where chemical exposure is common, such as restaurants or factories. Residential flat roofs may also use PVC, even with the higher cost relative to other options, though the energy savings can help to offset that.

Installation Requirements
PVC roofing installation is complex and requires heat welding seams; certified professionals are required.

Climate and Regional Considerations
PVC roofs are ideal for hot and sunny climates due to their reflective properties, but also does well in regions with temperature extremes.

Maintenance and Repair Considerations
PVC is tough, but seams and adhesives should be checked regularly. Flat roof membrane repair can be somewhat costly, particularly if neglected too long.

Energy Efficiency
PVC roofing membranes reflect heat very well and have good insulation value. This leads to reduced cooling costs and high energy efficiency—great for hot climates.

Single Ply Roofing Comparison Summary

TPO vs PVC Roofing

  • PVC costs more but lasts longer than TPO roof systems.
  • TPO membrane roof installation runs cheaper.
  • PVC handles chemicals better.

TPO roofing vs EPDM roofing

  • TPO reflects more heat than black EPDM rubber roof materials.
  • EPDM costs less to buy and install.
  • TPO seams stay stronger longer.

EPDM roofing vs PVC roofing

  • PVC cost more but lasts longer than EPDM roofing material.
  • EPDM repairs cost less and require fewer specialized skills.
  • PVC handles chemicals and standing water better.

Muti Ply Roofing

In this section we’ll break down three major options multi ply roofing options: Built Up Roofing (BUR), Modified Bitumen, and Hybrid Systems. In contrast to Single Ply systems, these roofing materials are made with multiple layers, which why they are multi ply.

Built Up Roofing (BUR)

Material Composition and Characteristics
Built up roofing consists of alternating layers of bitumen (asphalt or coal tar) and reinforcing fabrics. These layers are “built up” to create a thick, durable and waterproof roof that is then topped with a layer of aggregate, such as gravel or coating.

BUR Sub-Categories. BUR can generally be installed using two different approaches:

  • Hot-Applied (Heat Activated): Asphalt is hot-applied to create the roofing seal.
  • Cold-Applied (Adhesive Based): Uses cold-adhesives rather than heat for component layers.

Typical Lifespan
BUR roofs last about 20 to 30 years, often depending on the quality of the materials and the level of care and maintenance.

Cost
BUR systems typically have high installation costs due to the labor involved in applying multiple layers. Long-term maintenance costs are usually lower if routine maintenance is performed. A built-up roof generally insulates very well, but heat reflection is dependent on the top layer applied.

Advantages and Disadvantages
BUR is known for being very tough and long-lasting, making it resistant to water and weather damage, and giving it a strong fire rating. However, installation can be labor-intensive and more expensive. It can also release unpleasant fumes during application, especially with hot-applied methods. The multiple layers are also very heavy, which necessitates strong roof support.

What Types of Structures Might Use This Material?
BUR roofing is suitable for both commercial properties and residential buildings. It’s often used on low slope roof systems because of its durability.

Installation Requirements
BUR installation requires experience – especially for hot-applied options. The process involves applying multiple layers and ensuring even coverage, which can take time and training.

Climate and Regional Considerations
BUR works well in most climates, as the multiple layers handle temperature changes. Gravel or topping can help prevent sun damage and block UV rays, but may be less efficient than other options.

Maintenance and Repair Considerations
BUR is relatively low-maintenance, but regular inspections can catch problems early. Should cracks or tears form in the bitumen layers, repairs can get costly. The gravel topping likely needs to be replaced periodically.

Energy Efficiency
Though its thick layering helps with insulation, BUR may not be the best at reflecting heat, which can be a drawback for energy efficiency in hotter regions.

Modified Bitumen

Material Composition and Characteristics
Modified bitumen is an evolution of BUR. It uses a flexible, waterproof bitumen combined with rubber compounds for better movement and flexibility. It comes in rolled sheets that are typically applied to the roof in layers.

Sub-Categories. There are two common types of modified bitumen roofs:

  • SBS (Styrene-Butadiene-Styrene): Provides more flexibility and is usually applied with cold adhesives or hot-mopping.
  • APP (Atactic Polypropylene): Reinforced with a stronger torch-down membrane for increased durability.

Typical Lifespan
Modified bitumen roofs can last 15 to 30 years, depending on the type and maintenance involved.

Cost
Modified bitumen roofs are generally cost-effective, with installation being quicker compared to BUR systems. SBS systems may have slightly lower installation costs since they often use adhesives. In terms of long-term maintenance, modified bitumen roofs are quite affordable because they are less prone to large-scale damage.

Advantages and Disadvantages
Modified bitumen is flexible and can accommodate building movement without cracking. It’s also easier to install relative to a traditional BUR roof system. However, APP systems require careful installation to avoid fire risks due to the use of a torch to apply the roof. They’re also less puncture resistant than BUR roofs and may require more maintenance.

What Types of Structures Might Use This Material?
This material is popular on both residential and commercial buildings. Modified bitumen is often preferred on buildings in seismic areas.

Installation Requirements
SBS systems are installed using adhesives or hot-applied techniques, making the installation process simpler than BUR. APP modified bitumen requires heat-welded seams, meaning skilled professionals must handle torch-down roofing application.

Climate and Regional Considerations
These roofs hold up well in most climates. Modified bitumen offers excellent resistance to UV rays and weather conditions, making it ideal for most regions. As a rule of thumb, SBS works better in cold areas, while APP is better in hot areas.

Maintenance and Repair Considerations
Like BUR roofing, modified bitumen roofs require regular checks, especially around seams. Fortunately, issues are usually easy to spot and repair, making flat roof repair straightforward.

Energy Efficiency
It can offer some insulation benefits, particularly with SBS systems. A white surface is needed to get the best energy-saving performance, especially in hot climates.

Built Up Roof vs. Modified Bitumen Comparison

Built up roof systems offer longer life and better durability through multiple layers. Modified bitumen roofing brings easier installation and lower costs. BUR provides extensive protection for heavy-duty structures, whereas modified bitumen is suited for buildings where flexibility is crucial.

Hybrid Roofing Systems

Material Composition and Characteristics
Hybrid roofing systems combine elements of BUR and modified bitumen. These systems use the layered structure of BUR along with the enhanced flexibility and ease of application found in modified bitumen.

Typical Lifespan
Hybrids can last 20-30 years with proper care, giving them a potential edge in longevity.

Cost
Hybrid systems come at a higher installation cost compared to BUR or modified bitumen alone. However, they benefit from the durability and flexibility of both systems, resulting in fewer repairs and possibly lowering maintenance costs over the long term.

Advantages and Disadvantages
These systems provide the best features of BUR and modified bitumen systems. They also offer very good protection against water, UV, and temperature fluctuations. The downsides are higher installation costs, complex installation, and the need for contractor expertise.

What Types of Structures Might Use This Material?
Hybrid systems are best for commercial structures like office buildings, malls, or industrial complexes where long-term durability is key.

Installation Requirements
Installation is complex and requires very skilled professionals.

Climate and Regional Considerations
With layers from both systems, hybrids can stand up to most climates, and the layers can be tailored for the local climate.

Maintenance and Repair Considerations
Regular professional inspection is essential, as repairs can be complex and expensive. However, strong preventative maintenance will go a long way in preserving the longevity of a hybrid system.

Energy Efficiency
Hybrid systems provide good insulation, and different surface options can help with heat reflection.

Other Flat Roof Materials

While we’ve covered many of the most common types of flat roofing materials, there are several more that are worth mentioning. Not all of these roofing materials are common, or well suited for a home or business, but they’re worth knowing about.

Metal Roofing

Material Composition and Characteristics
Metal roofing uses materials like aluminum, steel, or copper. It’s durable, lightweight, and often comes in large panels or sheets. It’s generally coated with a protective finish to improve its rust resistance. This roofing is smooth but solid, making it ideal for shedding rainwater and snow.

Sub-Categories:

  • Aluminum: Lightweight, resistant to rust, but can dent easily.
  • Steel: Heavier, durable, and often used when impact resistance is needed.
  • Copper: More expensive and used for its aesthetic appeal.

Typical Lifespan
A well-maintained metal roof can last 40 to 70 years, making it one of the longest-lasting flat roof materials.

Cost
Metal roofing can be more expensive compared to other flat roofing materials. Installation costs are also higher due to the need for specialized skills. However, its durability and minimal maintenance requirements can lead to lower long-term costs. Energy savings may vary, depending on the finish and materials used.

Advantages and Disadvantages
One major advantage of metal roofs is durability and fire resistance: they stand up well to extreme weather, which makes them more common in regions that experience harsh conditions. They can also give a building a distinctive aesthetic. However, metal roofs are prone to noise during heavy rain or hail. And, of course, the high upfront installation costs can be a major barrier.

What Types of Structures Might Use This Material
Metal roofing is often found on commercial buildings, industrial warehouses, storage units, and homes in areas prone to harsh weather. It’s especially useful for low slope roof systems.

Installation Requirements
Metal roofing requires precise installation techniques so specialized professionals are needed. Proper substrate support is critical to prevent sagging. Large panels reduce the number of seams, but improper installation greatly increases the risk of leaks and issues.

Climate and Regional Considerations
Metal roofing performs well in almost any climate. In snowy regions, it helps shed snow, while in coastal areas, aluminum resists rust and is highly durable.

Maintenance and Repair Considerations

Once installed, metal roofs require little maintenance, aside from periodic checks for rust or loose screws. Repairs can be costly if damage occurs to large sections.

Energy Efficiency
Metal roofs reflect sunlight, reducing cooling costs in warmer regions. Some metals also pair well with reflective coatings for added efficiency. Additional insulation can also improve energy performance.

Spray-On Roof Coatings

Material Composition and Characteristics
Spray-on coatings are applied as a liquid and are typically made from silicone, acrylic, or polyurethane. Once cured, they form a waterproof membrane that can be used to cover an existing roof.

Typical Lifespan
These coatings last around 10 to 20 years, although this can vary based on the quality of the application and climate conditions.

Cost
The cost of spray-on coatings is relatively low. Installation is straightforward, which keeps labor costs down, but can vary depending on the surface preparation needs. Maintenance is affordable, but frequent re-coatings may be needed to extend the lifespan.

Advantages and Disadvantages
Spray-on coatings are quick to apply, especially for complex shaped roofs, and can extend the life of an existing roof. There are also no seams to leak. However, they are relatively less durable and long lasting than other flat roof types and aren’t always suitable.

What Types of Structures Might Use This Material?
Spray-on coatings are ideal for commercial flat roofs, mobile homes, garages, and other buildings needing quick waterproofing or flat roof leak repair.

Installation Requirements
This material requires a smooth, prepped surface, so installation can be weather dependent. It’s applied using specialized spray equipment, making it important to ensure the roofer has experience applying these coatings.

Climate and Regional Considerations
Spray-on coatings work well in mild climates, but harsher regions with extreme weather may wear them out faster.

Maintenance and Repair Considerations
Periodic re-coating is necessary to maintain water resistance. The repairs for small cracks or worn areas are easy, but major damage may warrant a replacement.

Energy Efficiency
Many spray-on coatings come in white, reflecting sunlight and offering an energy-efficient option to keep buildings cooler.

Roll Roofing

Material Composition and Characteristics
Roll roofing is made from asphalt-impregnated material. It comes in rolls, typically 36 inches wide, and is often applied to low-slope roofs.

Typical Lifespan
This material usually lasts 5 to 10 years, making it one of the shorter lifespan options.

Cost
Roll roofing is inexpensive, both in terms of materials and labor. It’s easy to install, which keeps costs down even further. However, its short lifespan may offset these savings due to more frequent flat roof replacement.

Advantages and Disadvantages
Roll roofing is easy to install and relatively cheap. On the downside, it’s not as durable as other flat roof materials, making it more prone to leaks and damage.

What Types of Structures Might Use This Material?
Roll roofing is mainly installed on sheds, garages, and smaller residential structures with low slope roofs because of its lower strength and shorter lifespan.

Installation Requirements
Installation is simple. It’s rolled out and then nailed or glued down. Some roofers use torch-down techniques to ensure a secure bond.

Climate and Regional Considerations
This roofing doesn’t hold up well against severe weather, making it better suited for areas with mild conditions. Hot regions can cause it to warp.

Maintenance and Repair Considerations
Roll roofing doesn’t require much maintenance, but repairs are common due to its limited durability. Patching small tears or punctures is usually an easy fix.

Energy Efficiency
Roll roofing offers very little energy efficiency due to its dark color and lack of insulating properties, another reason it’s commonly used on sheds and garages.

Green Roofs

Material Composition and Characteristics
Green roofs consist of layers including membrane roof materials, drainage boards, soil, and vegetation on top of a waterproof layer.

Sub-Categories:

  • Intensive Green Roofs: These have deeper soil, supporting a wider variety of plants.
  • Extensive Green Roofs: These have shallower soil, requiring less maintenance but limiting plant choices.

Typical Lifespan
Green roofs can last 30 to 50 years if installed and maintained properly, matching longer-lasting roofing systems like EPDM roofing.

Cost
Green roofs are expensive to install due to the extra layers involved. The long-term maintenance varies depending on the plants, but expect some regular maintenance costs. Energy savings from the insulation they provide may offset some of these costs.

Advantages and Disadvantages
Advantages include the added insulation, as well as aesthetic and environmental benefits, but they require complex installation, ongoing maintenance, and a strong building structure to support the added weight.

What Types of Structures Might Use This Material?
Green roofs are more commonly found on commercial and institutional buildings but can be installed on certain residential flat roofs, provided the structure is strong enough.

Installation Requirements
Green roofs need professional installation. Careful attention must be given to choose the right plants for climate conditions and include a watertight membrane.

Climate and Regional Considerations
Green roofs are best for areas with adequate rainfall or irrigation. The plants chosen for the roof need to be well-suited to the local climate.

Maintenance and Repair Considerations
Regular maintenance is required for the plants. The underlying roofing membranes also need periodic checks for leaks or damage.

Energy Efficiency
Green roofs provide excellent insulation, keeping buildings warmer in winter and cooler in summer. They lower energy bills over time.

Conclusion: flat roof material types

Flat roofs have many material options and systems, but the best pick depends on your building’s needs and your budget.

Whether you’re looking for EPDM rubber roofs for their flexibility and affordability or prefer TPO roofing material for its energy efficiency in warmer climates, your choice will come down to the specific requirements of your property. Modified bitumen roofs offer a durable multi-ply solution, while BUR roofing provides time-tested strength. If you’re looking for flat roof repair or installation, reach out to one of the top Washington DC roofers for a free quote and top quality workmanship.

Certain types of materials are far more common on commercial flat roofs, especially those that need durability and energy efficiency.

Regardless of the selected flat roof materials, knowing the best fit for your climate, structure, and budget can help you make the right decision.