Roofing Systems - PCR Commercial Roofing - Lewisville, North Carolina

ROOFING SYSTEMS - Understanding their pros, cons and what they are

TPO (Thermoplastic Polyolefin Roofing)

TPO (Thermoplastic Polyolefin roofing) is a single-ply roofing membrane used on flat or low-sloped roofs. It’s made of a blend of polypropylene and ethylene-propylene rubber and is designed to be incredibly durable, energy-efficient, and easy for commercial roof installations too. TPO roofing has quickly become one of the most popular single-ply roofing membranes in the country due to its many positive properties, including recyclability, UV resistance, and affordability.

The Pros of TPO:

Energy Efficient: Bright-colored TPO roofs reflect the sun’s harmful UV rays, helping keep internal temperatures cool while preserving the outer membrane of the roof. TPO roofing is available in many different colors, although most of the TPO roof colors you will find are white and gray.

Puncture Resistant: Punctures can occur from falling debris or human errors, TPO is a strong membrane the higher the mil is the harder to pierce. Punctures are one of the leading causes of leaks on low-slope roofs.

Cost Effective: TPO roofing has become very popular thanks to its strength and durability, as well as its low material and labor costs. When you choose TPO roofing, you truly get the best of both worlds. A TPO roof is a sound investment because it doesn’t break the bank to install, and with the proper maintenance program in place, it can last a very long time.

Weather-tight Solution: TPO is a monolithic roofing system that is heat-welded together, forming a strong bond that enhances weather resistance

The Cons of TPO

TPO membrane can lose its elasticity over time.

Effective welding requires extensive experience. Only the certified contractors should be considered when installing a TPO roofing system.

Not recommend in areas with high Chemical contamination.

There are many DIY projects that property owners can take on to save some money, but commercial roofing installation is NOT one of them! We recommend that all commercial building owners and managers hire a trusted and experienced roofing contractor to install their TPO roofs.

The truth about TPO roof installation is that while it is not heavily labor intensive, like some other roofing options, it still requires the use of specific tools for the heat welding process, which is critical to achieving a strong weld.

There are four main techniques for installing TPO roofing:

Induction Weld: This method involves using the game-changing induction welding machine system that allows an experienced crew to adhere a TPO roof membrane to the underlying plates for a fast and incredibly strong heat weld.

Adhered: With an adhered TPO roof system, the iso board and underlayment are fastened to the decking, while a layer of adhesive is applied to the sheet of TPO that is rolled out across the roof. The slightly overlapping sheets of TPO are heat welded together.

Mechanically Fastened TPO: This method involves installing screws, at the ends of the TPO rolls to attach the sheet to the substrate. Then, like other methods, an overlapping piece of TPO is heat welded to create a seam and weatherproof the membrane. This is another one of the most common installation methods.

Ballasted: This method of TPO roof installation uses river washed rocks (ballast) to hold down the TPO membrane onto the roofing underlayment with heat-welded seams. Ballasted roofing is becoming increasingly rare in the roofing industry but is still used in special situations.

When compared to other options on the market TPO roofing is relatively affordable. When deciding on roofing material, especially as it relates to pricing, be sure to factor in all of the variables. The cost of the roofing material, specialty equipment and the cost of labor are typically the biggest cost factors that property owners and managers consider, so be sure to choose a reputable roofing company that has the knowledge and tools that are specifically needed for TPO roof installation.

PVC Roofing (Polyvinyl Chloride Roofing)

PVC roofing systems have been installed since the 1960s and were one of the first single-ply materials used in roofing. PVC roofs come in many thicknesses, and they are typically white, tan, or gray in color. A PVC membrane installation can be mechanically attached, fully adhered, induction welded or ballasted. Like TPO roof systems, PVC membrane rolls, and flashing membranes are heat welded together, creating the strongest bond available in a roofing system.

A PVC roof installation is heat welded together. For welding the seams on open membrane rolls, an automatic “robotic” welder is used that automatically sets the correct temperature, applies the perfect pressure, and sets the best speed to perfectly weld the two membrane sheets together. For smaller areas, like rooftop units and curbs, a hand-held heat welding gun is used, along with a rubber roller.

Some benefits of a PVC roof are:

Proven system that has been around for over 60 years.

Easy to repair.

Resistant against a variety of chemicals.

Energy Efficient: PVC roofs reflect the sun’s harmful UV rays, helping keep internal temperatures cool while preserving the outer membrane of the roof. PVC roofing is available in many different colors, common colors are white and gray

On higher-end PVC roof systems, puncture and grease resistance can be exceptional. However, this often comes at a big premium. Due to the KEE membranes.

PVC system drawbacks include:

More expensive than TPO roof systems or EPDM roof systems.

Can become brittle as life term is nearly up.

PVC membrane can lose its elasticity over time.

Effective welding requires extensive experience. Only certified contractors should be considered when installing a PVC roofing system.

There are four main techniques for installing PVC roofing (very similar to TPO):

Induction Weld: This method involves using the game-changing induction welding machine system that allows an experienced crew to adhere a PVC roof membrane to the underlying plates for a fast and incredibly strong heat weld.

Adhered: With an adhered EPDM roof system, the iso board and underlayment are fastened to the decking, while a layer of adhesive is applied to the sheet of PVC that is rolled out across the roof. The slightly overlapping sheets of EPDM seamed and bonded together. Afterward, a crew member will go over the top of the EPDM with a roller to flatten out the roof and eliminate bubbles/imperfections.

Mechanically Fastened:Mechanically attached EPDM roofing systems are held in place at the seams by a line of screws and fastening plates that keep the membrane attached to the substrate of the roof. Once the edges of the rolls of the membrane are attached to the screws and plates, the overlapping pieces of EPDM are bonded together with adhesives to achieve a weatherproof seal.

Ballasted: This old-fashioned process works by placing rocks and stones on top of a roofing substrate like EPDM to hold it down and fight against natural threats like wind damage. While a less-skilled option, ballasted roofing is labor-intensive and adds loads of unnecessary weight to a roof, considering more modern applications.

EPDM (Ethylene Propylene Diene Monomer)

EPDM (Ethylene Propylene Diene Monomer) is a resilient, single-ply, synthetic rubber material that has stood the test of time as a roofing material in the commercial building sector. Fortunately for property and business owners around the country, EPDM is on the lower end of commercial roofing solution pricing.

Pros of EPDM

Durability: One of the primary benefits of EPDM roofing lies in its extraordinary durability. This roofing material is designed to withstand the test of time with resistance to UV rays, extreme weather conditions, and temperature fluctuations. With a lifespan that can extend up to 50 years or more, under the right conditions.

Easy to Repair: Another key advantage of EPDM roofing is its repair-friendly nature. While the material is tough, in the unlikely event that a section gets damaged, it can be easily patched up. This means fewer instances where a full roof replacement is needed, which offers massive time and money savings in the long term.

Environmentally Safe: One of the primary benefits of EPDM roofing lies in its extraordinary durability. This roofing material is designed to withstand the test of time with resistance to UV rays, extreme weather conditions, and temperature fluctuations. With a lifespan that can extend up to 50 years or more, under the right conditions.

EPDM system drawbacks include:

Bridging/ tenting at walls or flashing first sign of advanced aging.

EPDM membrane can lose its elasticity over time.

Becomes UV unstable and common repairs may not be an option any longer.

There are three primary ways that EPDM roofing can be installed on a commercial property:

Adhered: With an adhered PVC roof system, the iso board and underlayment are fastened to the decking, while a layer of adhesive is applied to the sheet of PVC that is rolled out across the roof. The slightly overlapping sheets of PVC are heat welded together.

Mechanically Fastened: This method involves installing screws, usually every 12 inches, at the ends of the PVC rolls to attach the sheet to the substrate. Then, like other methods, an overlapping piece of PVC is heat welded to create a seam and weatherproof the membrane. This is another one of the most common installation methods.

Ballasted: This method of PVC roof installation uses river washed rocks (ballast) to hold down the PVC membrane onto the roofing underlayment with heat-welded seams. Ballasted roofing is becoming increasingly rare in the roofing industry but is still used in special situations.

Sloped

Sloped Roof systems, in one form or another, have been around as long as buildings have. Clay tile roof systems, for example, have been used for thousands of years, going back to the ancient Egyptians and maybe even further. The most common type of sloped roof system installed today is asphalt roof shingles, which have been around since the early 1900s. They are installed on a majority of buildings today due to their price, durability, proven performance, superior aesthetics, and ease of installation.

The most common design options for an asphalt roof system are 3-tab shingles or architectural shingles. 3-tab shingles look flat from the ground, whereas architectural shingles have more of a dimensional look and tend to be of higher quality. asphalt shingle colors vary between manufacturers, but they tend to match or complement colors typically used in other areas throughout the building. With asphalt roof shingles, typically, the heavier the shingle, the longer it will last. Some features, such as self-sealing strips, also make a big difference in terms of longevity, weatherproofing, and performance in high-wind areas. Different manufacturers also use varying technology to maintain the color over time and prevent moss buildup.

Asphalt Shingle roof systems are the most common type of sloped roof system installed for a variety of reasons.

Some advantages of an asphalt roof system are:

Proven system that has been around for over 100 years.

Extremely durable and strong puncture resistance.

Variety of colors and styles to choose from.

Excellent opportunity to improve the aesthetics of a building.

Typically less expensive than a flat membrane roof system.

Asphalt Shingle roof systems have a few disadvantages, which are:

Warranties are typically materials only and do not include labor.

Requires a slope to perform effectively. Most manufacturers recommend a 4:12 slope or greater without a full ice and water shield.

Types of Rigid Insulation

Polyisocyanurate (Polyiso) Insulation: Known for its high R-value per inch, polyiso is a popular choice for commercial roofing. It is lightweight, moisture-resistant, and offers excellent thermal performance. Polyiso is often used with a facing material, such as foil or fiberglass, to enhance its durability and fire resistance

Extruded Polystyrene (XPS) Insulation: XPS is a durable, moisture-resistant insulation material that provides consistent thermal performance. It is often used in applications where moisture resistance is crucial, such as below-grade or inverted roofing systems. XPS insulation is known for its high compressive strength and resistance to water absorption.

Expanded Polystyrene (EPS) Insulation: EPS is a cost-effective insulation material that offers good thermal resistance and versatility. It is lightweight and can be used in various roofing applications, including tapered insulation systems for proper drainage. Compared to XPS, EPS is less resistant to moisture but can be treated with water-resistant coatings.

High-Density (HD) Coverboard: HD coverboards, such as those made from gypsum, cement, or HD polyiso, provide a durable and stable substrate for roofing membranes. They enhance the roof system’s impact resistance, fire resistance, and wind uplift performance. HD coverboards are often used in combination with other insulation materials to create a robust roofing assembly.

Fiberboard Insulation: Fiberboard insulation is designed to be an inexpensive way to create a separation between two roof systems. Unfortunately, it does a very poor job resisting moisture and has a habit of soaking up water over time. Typically, it is only used in situations where low cost is the main factor.

Perlite Insulation: Perlite is a lightweight, volcanic glass material that is often used as a coverboard or secondary insulation layer. It can also be installed as the first layer of insulation, directly over the structural decking, to increase the fire rating of the roof assembly. It provides good thermal performance and dimensional stability. Perlite insulation is resistant to moisture, fire, and decay, making it a durable option for commercial roofing systems.

Composite Insulation Boards: These boards combine different types of insulation materials to leverage their individual benefits. For example, a composite board might consist of a layer of polyiso insulation bonded to a layer of HD coverboard. This combination provides high thermal resistance, durability, and impact resistance.

Each type of rigid insulation has its specific advantages and is chosen based on the unique requirements of the commercial roofing project, including thermal performance, moisture resistance, fire resistance, and structural support.

Rigid Insulation can either be installed over the structural deck or directly over the existing roof system. Rigid insulation is used to provide a substrate between the membrane and structural decking. It is also used to increase the energy efficiency, or “R-value” of your roof system.

For most flat roofing applications, the rigid insulation is fastened down to the structural deck using fasteners. This is known as a mechanically fastened installation and can be used for mechanically attached membrane systems or fully adhered membrane systems.

If the structural deck is not strong enough to fasten into, or if fastening into the deck will be highly disruptive to the building’s operations (concrete decking, for example), the rigid insulation can also adhere to the deck. This uses a 2 part foam adhesive known as an install-stick or only bond, based on the manufacturer you are using. Typically, adhering the insulation to the structural deck is used in conjunction with fully adhered membrane systems.

Most flat roofing systems require some kind of rigid insulation under the new roofing system. The biggest reason is that all flat roofing systems require a substrate between the structural decking and the new roof system. The second and more obvious reason is for higher R-values, which building owners are asking for, and building codes throughout New England are requiring.

What is Modified Bitumen Roofing?

Modified Bitumen (MOD-BIT) Roof Systems have been installed since the mid-1970s. A Modified Bitumen roof system is typically installed with 1-3 ply and comes in a wide variety of colors. There are many ways to install a modified bitumen roof, but the four most common methods are cold-applied (liquid adhesives), torch-applied (torch with open flame), hot-applied (hot asphalt) and self-adhered (adhesives built into the sheet)

Modified Bitumen systems are typically seen as the next generation of asphaltic or pitch-based Built-up roofs (BUR). It carries many of the same strengths as a traditional BUR roof system, while the Modified Bitumen installation can be completed using a much safer and less expensive method. We typically install self-adhered MOD BIT roof systems at PCR Commercial Roofing due to their safe and effective installation technique. Self-adhered Modified Bitumen roof systems are similar to fully adhered single-ply roofs in that the entire system adheres to the self-adhered Modified Bitumen roof installations are completed by:

Fastening the rigid polyisocyanurate insulation to the steel deck.

Then, on the first ply, which is called the ply base, the backing paper is peeled off. Then, the ply base is placed over the rigid insulation and then rolled in.

Now that the ply base is fully installed, each additional ply, known as the mid-ply, is installed directly over the last ply. If it is only a two-ply system, this step is skipped.

Finally, the last ply, known as the cap sheet, is installed in the same manner, with the cap sheet being rolled into the mid-ply.

Some of the benefits of Modified Bitumen roof systems are:

Proven system that has been installed for over 40 years.

Proven performance of asphalt, which is known to go the distance.

Strongest puncture resistance of any roofing system.

Available in a wide variety of colors with little to no quantity restrictions.

Modified Bitumen roof systems have a few disadvantages, which are:

1-ply modified bitumen roof systems have not shown any long-term success.

Very high cost if there are 2-3 ply that require labor and materials to install.

Asphaltic-based roofs rely on granules for protection from the sun. Without granules, Asphalt-based roofs crack and break apart.

If granules are not included with your modified roof system (known as a smooth surface mod-bit), the materials must be coated with an aluminum roof coating, or the surface will show accelerated aging. Typically, periodic recoating will be required.

Modified Bitumen roofs systems age prematurely if used on roofs that hold any water.

Some installation methods, such as torch down, are very unsafe and pose a major risk to your building.

PCR Commercial Roofing will not install any 1-ply Modified Bitumen roof system and will not use any open flame torch application methods. Modified Bitumen roof systems are a great option for roof systems that have heavy foot traffic or an increased likelihood of punctures. Roofing modified bitumen is also great for any roof system that requires a certain color that is unavailable in a single-ply membrane.

BUR

Built-up roof systems (BUR) are the oldest roof systems that are still being installed today, even though a new BUR roof installation is rare. They have been installed since the mid-1840s and, like modified bitumen roofs, are typically installed in 2-5 plys. BUR roofs come in black and need to be covered by either gravel or granules to prevent cracking caused by heat from the sun. BUR roofs are installed by hot-mopping. The product itself comes in a solid form and needs to be broken down into smaller pieces. Once broken down, the pieces are thrown into a heated kettle, where it is cooked to 400 degrees.

At 400 degrees, the product turns from a solid into a liquid, where it can be picked up by a mop or bucket and spread across the roof. After the product is spread, felt or fiberglass-based paper is applied over the liquid product which, as it cools off, turns back into a solid again. Once the felt paper is applied, another layer of liquid asphalt or pitch can be applied right over it.

Some of the benefits of Built-up roof systems are:

Proven system that has been installed for over 150 years.

Proven performance of asphalt, which is known to go the distance.

Excellent puncture resistance.

Built up roof systems have a few disadvantages, which are:

Very high cost since there are 2-5 ply’s that require labor and materials to install.

Asphaltic-based roofs rely on gravel or granules for protection from the sun. Without them, asphalt-based roofs crack and break apart.

Mop-down installation methods are very unsafe for the workers.

Asphalt products don’t last as long as they used to.

Much heavier than comparable single-ply roof systems, since 2-5 plys of heavy product are installed.

Very few contractors still have the required equipment to install a BUR roof

Thank You!

We understand that your roof is a crucial part of your home, and we're here to help keep it in top shape. If you have any concerns or need a professional inspection, don’t wait—call us now! Our experienced team is ready to give you the peace of mind you deserve.