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8 Types of Commercial Roofing Systems

Your commercial building’s roofing system is critical to your business’s operations — it shields you and your company’s assets from the natural elements, helps maintain the inside temperatures comfortable and keeps rain far from the foundation. However, there are many types of roofing systems, and choosing the right roofing type for your business can be a time-consuming endeavor. This guide provides comparisons of the best commercial roofing systems and the pros and cons of each roof covering type.

1. Ethylene Propylene Diene Monomer (EPDM)

Ethylene propylene diene monomer (EPDM) roofs are highly durable and a common option for roofs with low slopes. They consist of a resilient synthetic rubber membrane that commonly contains two primary ingredients — propylene and ethylene. The color of the membrane is either white or black, and it comes in different thicknesses and widths. EPDM systems can be glued, ballasted or attached mechanically. Seams are sealed using a special tape or liquid adhesive.

The advantages commonly associated with EPDM roofs include its:

  • Resiliency: EPDM systems can last for several decades, assuming they are correctly installed and well maintained.
  • Resistance to damage: EDPM roofs are resistant to damage from UV rays, thermal shock and hail.
  • Recyclability: When reroofing, EDPM can be recycled.

There are also several cons associated with this roofing system, which include the following:

  • Difficult installation: For the seams on EPDM to be properly sealed, the conditions must be dry and clean.
  • Reactivity with other products: They also cannot be installed in direct contact with asphalt products. Chemical reactions between adhesives and materials can lead to blistering due to insufficient curing.
  • Hot: Black EPDM roofs will absorb heat.

2. Metal

Metal roofs are attractive, insulating and often quite durable. They come in various metals, including galvanized steel, zinc, aluminum, stainless steel and copper, and often exist as a combination of more than one metal. They’re also covered with a coating that protects against UV rays and corrosion.

The design options for a metal roof depend on several factors, including the roof’s architectural features and existing slope. For a metal roof to perform well, a slope of at least 1:12 is generally required. Installation can be over an architectural panel or structural panel. You can also add insulation directly below the panels or in the attic for thermal resistance.

Some of the pros of commercial metal roofing include:

  • Longevity: A metal roofing system that is well designed and installed properly can last half a century. In combination with substrate insulation, they can easily meet today’s stringent energy code requirements.
  • Many options: They come in a wide array of systems and finishes.
  • Environmentally friendly: A metal roof is also environmentally friendly as the majority consist of recycled materials and can be recycled after they’ve come to the end of their usable life. If you opt for a light-colored metal roof, it will reflect heat, thereby reducing your energy costs.

Some potential disadvantages of a metal roof for your business could be:

  • Temperature-related problems: Fluctuations in temperature may lead to bending with some panel widths.
  • Potential for leaks: If your metal roof has an exposed fastener system, it may start leaking after a few years, although a proper, professional installation should prevent this.
  • Dangerous to walk on: Walking on any sloped roof is inherently dangerous, but metal roofs are particularly slippery. If your commercial building roof has lots of equipment or penetrations like skylights and vents, metal may not be the best choice for your roofing material.

3. Single-Ply Roofing

Single-ply roofing is currently the most popular commercial roofing system and comes in a broad array of options, thicknesses and prices. The most common types of single-ply roofs are plastic and rubber. The main advantages of this roofing type include:

  • Low installation cost: Installing single-ply roofing is relatively affordable.
  • Flexibility: A single-ply roof doesn’t put as much stress on the structure of your building as other roofing systems. Because they’re flexible, they stretch and adapt to the natural movement of your building.
  • Potentially lower utility costs: Single-ply roofing can be black, gray or white, and the option you choose will often depend on your climate. These roofing colors can help maximize heat-retaining or reflective qualities, thereby minimizing your building’s utility costs.

Single-ply roofing is not without its drawbacks, however. These include:

  • Shorter life span: Although single-ply roofing has a lower installation cost, this comes with a major tradeoff — a shorter useful life. Leaking often occurs at their seams, and many can show noticeable wear just five years after their installation.
  • Susceptibility to damage: Debris and foot traffic can easily damage a single-ply roof, and sometimes can even puncture it.

In recent years, an improved single-ply roofing system has been developed that feature cross-linked polymers. This addresses many of single-ply roofing’s disadvantages. They’re generally reinforced to be thicker, stronger, longer-lasting and more resistant to punctures.

4. Cool Roofs

Cool roofs are designed to reflect more sunlight and absorb less heat than standard roofs. They commonly feature highly reflective paints, shingles or tiles. Practically any building type can benefit from a cool roof, but before you decide to install one, consider your climate and other factors.

A cool roof can help your business reduce energy costs significantly. Other benefits of this roofing type include:

  • Less maintenance: One of the greatest draws of this roofing type is that it requires minimal maintenance and has a longer life span. However, it’s still recommended that your cool roof is routinely inspected.
  • Lower temperatures of your building: When a roof has a cool roof coating, the temperatures in the building will be cooler. Rather than absorbing the sun’s heat, a cool roof features reflective properties that help keep temperatures down.
  • Lower energy usage: Lower temperatures on your roof mean that your interior will be more comfortable for your employees. Lower temperatures mean your AC can enjoy some much-needed rest.
  • Better air quality: With your AC being used less, your building’s carbon footprint will decrease significantly. A cool roof can help you save money as you help out the environment.

If you’re considering installing a cool roof on your building, you’ll first want to figure out if the expense can justify your energy savings. The amount of energy you’ll save will depend on several factors, including the climate and environment, the degree to which your current roof is insulated and the efficiency of your cooling and heating systems.

If your company is building a new building, you can decide during your planning phase what roof type to install and whether it should be a cool roof. If you would like to turn an existing roof into a cool roof, you have three basic options:

  • Retrofitting your roof with special heat-reflective materials
  • Recovering your roof with a tile coating or other waterproofing surface
  • Removing your existing roof entirely and installing a cool one

If your current roof is in bad condition or nearing the end of its life, it’s generally best to replace your roof with a new one.

When deciding whether to invest in a cool roof for your business, you have several important factors to consider. These include:

  • Costs: Cool roofs aren’t necessarily more expensive than non-cool roofs, particularly if you’re installing a roof during new construction or replacing an existing roof. However, it can be pricey to convert a standard roof in good condition into a cool one. The main costs are the upfront installation and ongoing repair, cleaning and recoating. A cool roof can save your business money in various ways, including energy savings, incentives and rebates, extended roof lifetime and HVAC equipment downsizing.
  • Your climate: One of the most important factors to consider is your climate. You will enjoy the most savings from a cool roof installation if you’re in a hot climate, but if you’re in a colder climate, your energy costs in the winter might increase because of reduced heat gains, which are beneficial in colder weather.
  • Humidity: In warm, humid regions, the surface of a cool roof may be more vulnerable to mold or algae growth than in a drier climate. However, roof coatings with special chemicals can help prevent the growth of these organisms for several years. In colder climates, cool roofs can accumulate moisture via condensation, although this can be prevented with the right design techniques.

5. Foam Roofs

Spray foam roofs are another one of the popular commercial roof types for many businesses, and for many reasons, which include:

  • Ease of installation: A spray foam roof is installed by spraying liquid foam over an existing roof. This foam will expand and conform to the roof. Spray foam works with all roof sizes, shapes and materials. Furthermore, no expensive materials or equipment are required to install this kind of roof, which significantly cuts down on the price.
  • Energy efficiency: Spray foam serves as a barrier against thermal heat, air and moisture, meaning that it serves as excellent insulation for your building and your AC and heating units won’t need to work as hard to keep you and your employees comfortable. This will be reflected in your power bills, as well.
  • Low maintenance: Once the foam has been sprayed on, there’s very little you’ll need to do for the next 50 or more years. If damage does occur, such as a tear, you can have someone come out and fill the gap. This repair procedure is very different from repairs on other types of roofs on commercial buildings, where part of the roof often must be ripped up for repairs to be made.
  • Waterproof: One of the main reasons for roof leaks is because there are seams. A foam roof, however, is a seamless application. The foam is in liquid form when it is installed, allowing it to seep into existing cracks to make a seamless and waterproof seal. After application, the foam can also be leveled down to prevent water from pooling and causing water damage. Even if water does accumulate on the roof, cleaning and drying it is easy.
  • Durability: Roofs shrink and expand depending on outdoor temperatures. Unlike many other kinds of roofs, spray foam will move along with the roof, meaning there’s no chance of cracks due to stress.
  • Resistance to strong winds: If you live in a region prone to hurricanes, you won’t have to worry about your roof being damaged by strong winds.

Foam roofs are not without their drawbacks, however. Possible downsides include:

  • Small installation window: You can only install a spray foam roof in very specific weather conditions. For instance, if there is rain or ice the night before your installation was scheduled, you’ll have to postpone your roof installation. Basically, if there’s any moisture on the roof, the installation will not be possible. Finding the right time to install the roof can be frustrating, especially if you live in a rainy area.
  • Chance of over spraying: When working with spray outside, the wind could carry it away. This can be a major inconvenience for you, and it could also affect other buildings and vehicles nearby. While it won’t cause any health problems, your workers and clients won’t like finding bits of foam on their cars.

6. Tar and Gravel

Tar and gravel, or built-up, roofs have been a popular option for over a century. This roof type normally consists of layers of asphalt, tar and other supportive materials that serve as a base and stone or gravel as a top layer.

Some benefits of built-up roofs include:

  • Affordable installation: Installing a built-up roof is relatively easy and the materials are also reasonably priced compared to other industrial roof types.
  • Low maintenance: Once installed, they require very little attention outside of routine inspections and maintenance. Repairing the top layer is also fairly easy.
  • Durability: A built-up roof has multiple layers, including a seamless layer that makes it more waterproof. These multiple layers also mean it can withstand foot traffic better than most other industrial roofing systems. They are also effective at protecting against UV rays, which help to prolong the life span of the roof, reduce the temperature of the roof and prevent large temperature fluctuations in the building.
  • Longevity: When properly installed and maintained, tar and gravel roofs can last over three decades.

Some of the main disadvantages of built-up roofs are:

  • Lower performance in cold climates: Built-up roofs tend to perform better in warm or mild climates than extremely cold ones.
  • Toxic odors: When installing the roof, the asphalt and heated tar can release toxic odors.
  • Weight: The multiple layers of tar, asphalt and gravel or stone mean that built-up roofs can be quite heavy. For this reason, sometimes the roof joists must be reinforced to support the weight of a built-up roof.
  • Lack of charm: Built-up roofs are designed for functionality, not aesthetics. If your business has specified aesthetics, a tar and gravel roof may not be the best choice.

7. Thermoplastic Polyolefin (TPO)

Thermoplastic polyolefin (TPO) roofs are another popular commercial roofing option. This roof has a single-ply, flexible membrane that is either mechanically attached to the roof or glued down to it. It’s usually white, smooth and made of a rubber compound. TPO membranes come in several thicknesses and may even include a fleece backing to install on top of abrasive surfaces.

Other advantages of this roofing material include:

  • Eco-friendliness: TPO roofs are reflective, allowing your building to stay cooler in the summertime, which will lower your carbon emissions and energy use.
  • Flexibility: The flexible quality of TPO roofs means the material can be easily shaped around details of any roof and maintain its integrity when the building moves.
  • Long-lasting performance: When a TPO roof is installed, the membranes are heat-welded together at extremely high temperatures, creating fused seams. These fused seams provide over six times the strength of glued seams but are also flexible, which helps explain their longer performance.

The main drawback of TPO is its susceptibility to punctures. As TPO is a single-ply membrane, it’s vulnerable to punctures, making the underlying layers more vulnerable. If the TPO is less expensive, this means it is probably even more vulnerable. If a puncture occurs in a place on the roof where water pools, severe leaks could result. However, this can be largely alleviated if you opt for thicker membranes, specialized work pads and other improved types of industrial roofing materials.

8. Asphalt

Asphalt has been one of the most common roofing types for businesses for many years due to its durability and reliable performance. Most commonly found on low-slope or flat roofs, asphalt roofs consist of a weather-proofing layer, reinforcement layers and a protective surface layer. These roofs fall into two board groups:

  • Built-up roofing: Layers may include insulation, vapor retarder, a surfacing material and a membrane, which is made of layered components that are adhered and waterproofed using asphalt. These materials are all assembled on site.
  • Modified bitumen systems (MBS): This roofing type features a modified polymer, which provides the system with more strength and is assembled at the factory. it can be installed in one or multiple plies, similarly to built-up roofing.

Another option for an asphalt commercial roof is integrating materials like gravel and asphalt surfacing, aluminum, fiberglass, minerals, copper and various bitumen grades. Some advantages of asphalt include:

  • Exceptional performance
  • Durability
  • Multi-layer protection
  • Uplift protection
  • Fire and UV protection
  • Little required maintenance
  • Wide variety of materials to choose from

Both asphalt categories offer their own benefits. Built-up roofs, for example, are exceptionally good at resisting water, uplift, daily wear and tears resulting from foot traffic. It also has strong insular qualities, making your structure more energy-efficient.

MBS roofs, on the other hand, offer more flexibility and strength. They also offer more methods of application and are suitable for all climate types.

The major con of asphalt commercial roofing is its potentially tricky installation. For an asphalt roof to perform as it should, it must be installed properly, which requires expertise and specialized equipment. Built-up roofs are usually built on the surface of the roof using bitumen heated to at least 400 degrees F. The roofing crew must transport this hot bitumen to the roof and install it before it cools. However, there are cold adhesives alternatives, and certain MBS systems utilize open-flame heat welding for adhering asphalt already applied at a factory. If a roof installation needs an open flame or hot asphalt, the contractor must make a safety plan specific to the site.

Contact Capital Coating Commercial Roofing Services

Commercial roof coatings can be rolled or sprayed onto your existing roof to prolong its life span and protect it from damage. Here at Capital Coating, we offer spray foam and elastomeric coatings, which are exceptionally versatile, energy-efficient and long-lasting. If you want to know what is the best commercial roofing material for your business, we can offer guidance. Contact us to receive a free quote.