Are you considering a new flat roof for your home or commercial building? TPO (thermoplastic polyolefin) roofing systems are a popular choice in the industry. But what is it that sets TPO apart from other roofing materials? This article will explore TPO roofing from its composition to the installation process and compare it to other roofing materials. By the end, you’ll understand why TPO roofing is a top choice for flat-roof commercial buildings and whether it’s the right roofing system for your project.

Short Summary

• TPO roofing systems are a cost-effective and reliable option for commercial roofing and flat-roof properties, offering durability, heat reflection, and energy savings.
• Professional installation of a TPO roofing system is essential to its performance and longevity. Costs vary depending on material & labor factors but typically range from $6.00 to $14.00 per square foot for a complete TPO roof replacement.
• Ripped seams, punctured TPO, and pooling water lead to TPO repairs, but regular maintenance prevents a shortened lifespan.
• Before settling on a roofer to install or repair your TPO, ensure they have sufficient experience, licensing, references, and can provide a warranty.

Understanding TPO Roofing Systems

TPO roofing systems are a single-ply roofing membrane made with synthetic material and reinforcing scrim that provides a dependable and cost-effective roofing solution for commercial buildings and flat-roof properties.

Its UV resistance, heat-reflective properties, and flexibility make it popular among roofers, commercial contractors, and property owners.

TPO roofing is a relatively new addition to the roofing materials market, with about 33 years in existence. Still, it has already gained a reputation for its performance, especially on flat roofs.

Composition and Features

TPO is a single-ply three-layered membrane composed of a TPO polymer base, a polyester-reinforced scrim, and a TPO compounded top ply. Thermoplastic, in layman’s terms, means it becomes plastic when heated and hardens upon cooling.

TPO roofing offers superior stability and resistance to shrinking compared to EPDM, another popular thermoplastic membrane roofing material. An EPDM membrane can alligator, while TPO is less likely to shrink over time, resulting in a long-lasting, reliable system.

Furthermore, TPO roofing provides significant energy cost savings due to its highly reflective properties, which deflect the sun’s UV rays away from the building, keeping the interior cooler and reducing energy consumption.

Note: Geographic regions higher in altitude with high UV levels adversely affect the TPO and are often the number one problem TPO systems face in these regions.

Types of TPO Roofing Membranes and Their Thickness

TPO roofing membrane is typically sold in 45 mil, 60 mil, and 90 mil thicknesses, which is about the thickness of a heavy-duty trash bag. A thicker roof membrane should be considered for roofs that experience higher traffic (i.e., walkways or technicians routinely servicing rooftop units).

Two primary types of thermoplastic membrane roofing exist: Polyvinyl chloride (PVC) and thermoplastic polyolefin (TPO). TPO membranes have three layers, making them a highly durable and efficient choice for commercial buildings.

The TPO single-ply roofing membrane has gained popularity due to its energy advantages and durability. With its ability to resist heat and most UV rays, TPO roofing is an eco-friendly option that can yield significant energy savings for building owners.

TPO Roofing Installation Process

Following the specified installation process for TPO roofing is crucial to its performance and longevity. A high-level overview of installing TPO involves preparing the roof surface and substrate, choosing the proper insulation and thickness, attaching the membrane, and using a hot-air gun to weld the seams.

The heat-welded seams create a watertight seal that prevents leaks and protects your building’s interior. Hiring an experienced contractor to install TPO roofing is highly recommended due to the specialized tools and expertise required for a successful installation.

The layers of a complete, fully adhered TPO roofing system are as follows:

1. TPO membrane
2. Bonding adhesive (if fully adhered)
3. Cover board (recommended on roofs with regular foot traffic)
4. Insulation
5. Vapor barrier (optional, but roofs over concrete decking should always have a vapor barrier)
6. Underlayment (typically installed when an improved fire-resistive rating is required)
7. Roof decking

Preparing the Roof Surface

Before installing a TPO roof, the existing substrate must be appropriately prepared to ensure a successful installation. This involves cleaning, repairing, and priming the substrate to create an even surface for optimal adhesion. A flat surface is essential during installation to ensure proper adhesion of the TPO membrane and prevent water damage.

Priming the substrate is a crucial step in the installation process. It involves applying a primer to the substrate, ensuring optimal adhesion. Once the surface is prepared, and the insulation foam is installed, the TPO membrane can be attached securely to the roof deck, providing a durable and energy-efficient roofing system.

Insulation and Mechanical vs Adhered Attachment Methods

Insulation sheet foam is the component that dictates energy efficiency and must be installed to guarantee a satisfactory level of heating and cooling efficiency within the property. Several insulation options are available for TPO roofing, such as foam board or batt insulation. The type of insulation selected depends on the existing roof type, necessary insulation levels, as well as the specific needs of your building.

The TPO membrane can be mechanically attached using fasteners or attached using a fully adhered adhesive system. In mechanically fastened systems, the membrane is attached in the seams using fasteners and plates or battens. Fully adhered systems are completely bonded to the substrate beneath, creating a tighter and more secure looking TPO membrane. The bonding adhesives can’t be applied below certain temperatures. However, the adhesive in fully adhered systems evenly distributes the uplift pressure on the membrane and substrate, rather than focusing it on fastening points in the seams as the mechanically attached method does. This is why fully adhered systems typically have superior wind uplift results. Conversely, mechanically attached systems are often more cost-effective and have fewer installation restrictions. Each method offers advantages and is chosen based on factors such as the building’s structure, climate, and budget.

Regardless of the attachment method used, proper installation is crucial to ensure the longevity and performance of your TPO roofing system.

Comparing TPO Roofing to Other Roofing Materials

While TPO roofing is more expensive than some roofing materials, it offers several advantages that make it a popular choice for commercial buildings. Its highly reflective surface helps reduce energy costs by deflecting the sun’s UV rays away from the building. TPO is more energy efficient and durable than other materials like EPDM roofing.

However, TPO roofing also has some disadvantages compared to other materials. For instance, its lifespan is typically shorter than some roofing materials, lasting up to 25 years when installed correctly. Additionally, its quality may not be as certain as other roofing types since it is still a relatively new material.

Advantages of TPO Roofing

One of the main advantages of TPO roofing is its energy efficiency. The reflective properties of the TPO membrane help lower energy expenses by deflecting the sun’s UV rays away from the building, keeping the interior cooler, and reducing the need for air conditioning.

Secondly, TPO roofing is known for its resistance to mold and some puncturing, contributing to its durability and long-lasting performance.

Another advantage of TPO roofing is its eco-friendliness. Since it is a single-ply roofing membrane, it requires fewer manufacturing materials, resulting in less waste during production. Moreover, TPO material is recyclable, making it a more sustainable choice than other roofing materials that may end up in landfills.

Disadvantages of TPO Roofing

Despite its many advantages, TPO roofing does have some drawbacks. As mentioned earlier, the lifespan of TPO roofing is shorter when not well maintained compared to other materials like metal. TPO typically lasts from 15-25 years when installed correctly.

Additionally, TPO roofing membranes typically come in small-width rolls, resulting in seams every six to eight feet. These membranes experience contractions and expansions, and the seams are often where the membranes become loose, enabling water leaks.

In addition to more seams, TPO roofing membranes can have varying qualities depending on the manufacturer. Some manufacturers produce superior products, while others may construct lower-quality membranes. It is essential not to get swayed by price only but to choose a manufacturer with a long history and better reputation.

Lastly, TPO systems installed in high-altitude regions with high UV ray levels encounter a significant problem; as these conditions age the TPO quicker. Also, UV ray overexposure degrades the adhesives that attach the membrane and insulation to the substrate, causing the seams to separate and lose the watertight seal.

TPO Roofing Costs and Factors Affecting Pricing

TPO roofing costs can be broken down into two main components: materials and labor. An all-inclusive removal and installation of a TPO roofing system typically range from $6 to $14 per square foot, making it a competitive option. This includes material costs of $1.50 to $4.50 per square foot, labor costs of $3.50 to $7.50 per square foot, and the remaining $1.00 to $2.00 per square foot cost covers the removal and disposal of the current roofing material.

Several factors can affect your roof replacement and pricing of TPO, including hourly contractor charges, roof removal costs, climate, and accessibility. A roofing cost calculator is helpful, and it is essential to consider these factors when estimating the overall cost of your TPO roofing project, as they can significantly impact the final price.

Material Costs

The material costs associated with TPO roofing range from $1.50 to $4.50 per square foot for the TPO membrane system, while insulation costs vary. Commodity prices and supply chain dynamics impact TPO roofing material prices, so the timing of your project is a consideration and factor in your material cost.

Flashing is another essential component of TPO roofing, as it helps prevent leaks around seams and penetrations such as pipes, drains, chimneys, and skylights. The cost of flashing will depend on the specific requirements of your building and the complexity of the installation, so it’s essential to factor this in when estimating your overall TPO roofing costs.

Labor Costs and Installation Factors

Labor costs for TPO roofing typically range from $3.50 to $7.50 per square foot, depending on factors such as hourly contractor charge, climate, and accessibility. Considering these factors when estimating the overall TPO roofing cost is essential, as they can significantly impact the final price.

Roof removal cost is the third factor impacting your roof replacement and TPO installation. Typically $1.00 to $2.00 per square foot covers the removal and disposal of the current roofing system. Sometimes, this cost is just factored into labor and not itemized out separately.

However, when hiring a TPO roofing contractor, it’s crucial to obtain multiple quotes and compare labor costs and installation factors each contractor provides. This will ensure that you get the best value for your investment and select a contractor who can provide a high-quality installation at a competitive price.

Maintaining and Repairing Your TPO Roof

The first step in maintaining and repairing your TPO roof system is a regular and proactive inspection program. Your TPO needs regular maintenance and repairs to prevent water damage, preserve its integrity, and ensure a long-lasting roofing system. Maintaining your TPO roof includes cleaning debris, washing it with a light detergent, and inspecting it for damage to the membrane.

Commercial roofing companies offer maintenance plans to accommodate these needs. It is recommended to enlist the services of a professional roofer, as the maintenance professional will have the expertise and tools necessary to identify and address all issues necessary to preserve your TPO roofing system.

Regular Maintenance Tips

To maintain your TPO system, you must identify issues before they become significant problems that require costly repairs. Thus part of the technician’s routine is to regularly inspect for cracks, tears, or punctures in the membrane.

Additionally, removing debris and washing your TPO roof with a low-power pressure washer, gentle cleaner, and a soft-bristle broom is advised. This will help keep your TPO roofing system clean and free from dirt, which can cause damage over a prolonged period.

Furthermore, ensuring proper drainage will help prevent water from pooling on the surface and causing damage to your TPO membrane. Dysfunctional scuppers and clogged gutters will prevent water from escaping and cause pools of water on your TPO.

Note: Do not overlook routine maintenance, as a punctured or dirty TPO, compromised seams, degrading adhesion, or a TPO membrane with continual standing water will certainly have a shorter lifespan.

Common Repair Issues and Solutions

Common repair issues for TPO roofs include degrading seams, failed flashings, or a punctured membrane. A TPO patch is a common fix for areas that have been punctured or cracked. In some cases, small hot air welders can be used to make minor repairs to the seams of your TPO roofing.

Flashing on parapet walls and roof edges often needs re-flashing. Likewise, mechanical fastener issues and malfunctioning roof drains and scuppers call for repairs and immediate attention.

When TPO shows signs of severe deterioration or cannot be patched on its top surface, underside patch placement, and reverse-side welding can temporarily prolong its lifespan. However, eventually, a new roof will be necessary.

If you notice water entering your building or suspect your TPO system is damaged, contacting a professional roofer is essential. They can assess the situation, identify the problem, and recommend the best course of action to repair your TPO roof and protect your property from further damage.

Hiring a Professional TPO Roofing Contractor

Due to the specialized tools and expertise required for TPO roofing installation, hiring a professional TPO roofing contractor is highly recommended. They will ensure that your TPO roofing system is installed correctly and provides the desired performance and longevity for your commercial building.

When selecting a TPO roofing contractor, evaluating their experience, certifications, references, and warranties is essential. This will help you choose a reliable and qualified contractor for your roofing project and ensure that your TPO roofing system is installed correctly and efficiently.

Evaluating Contractors

To evaluate TPO roofing contractors, obtaining multiple quotes and comparing their expertise, certifications, references, and warranties is critical. This will help you select a reliable and qualified contractor for your roofing project and ensure that your TPO roofing system is installed correctly and efficiently.

Additionally, researching online customer reviews and ratings can provide valuable insight into the contractor’s reputation and the quality of their work. By evaluating potential TPO roofing contractors, including checking their membership with the National Roofing Contractors Association, you can feel confident in your decision and trust that your TPO roofing system will be installed to the highest standards.

Questions to Ask Before Hiring

Before hiring a TPO roofing contractor, you should ask several questions to ensure you select the best person for the job. These questions may include their experience with TPO roofing, certifications, pricing, warranties, and safety precautions.

By asking these questions and carefully considering the responses, you can make an informed decision about which TPO roofing contractor is the best fit for your project. This will help ensure that your TPO roofing system is installed correctly, providing you with a durable, energy-efficient, and long-lasting roofing solution for your commercial building.

Summary

In conclusion, TPO roofing systems offer a durable, energy-efficient, and eco-friendly solution for commercial buildings. Its unique composition and installation process makes it popular among building owners and roofing contractors. While TPO roofing may be more expensive than other roofing materials, its advantages, such as energy efficiency, durability, and recyclability, make it a worthwhile investment.

By performing regular maintenance and repairs, hiring a professional TPO roofing contractor, and carefully evaluating your options, you can ensure that your TPO roofing system provides the desired performance and longevity for your commercial building. So, if you’re considering a new roof for your property, TPO roofing may be the ideal choice to meet your needs and support your commitment to sustainability.

Frequently Asked Questions

What is TPO roofing?

TPO (Thermoplastic Polyolefin) roofing is a single-ply membrane composed of 3 layers: a TPO polymer base, a polyester-reinforced scrim, and a TPO compounded top ply. It was introduced in the early 90s and is used to create a watertight covering to protect the interior of a building.

TPO provides durable and cost-effective protection from the elements for many types of buildings.

How long does a TPO roof last?

A TPO roof can last up to 20 years with proper maintenance. TPO roofing material is thermoplastic polyolefin – a blend of ethylene propylene rubber and polypropylene components fused and reinforced with polyester fabric.

Well-cared-for TPO roofs can provide many years of protection from the elements.

Which is better, TPO or EPDM roofing?

When choosing the best roofing material for your project, deciding between TPO and EPDM can be difficult. Both offer significant advantages, so it’s essential to consider their respective features and the needs of your particular project to determine the better option for you.

TPO is a thermoplastic membrane that is highly resistant to UV radiation, making it an excellent choice for areas with high levels of sunlight. It is also highly resistant to punctures and tears, making it a great choice.

Why is TPO traditionally used for roofing?

TPO roofing material is a single-ply membrane designed to protect your commercial building from the elements. It’s traditionally used for roofing because of its durability and strength, making it ideal for harsh weather conditions. Its reflective surface also helps with energy efficiency.

What is TPO roofing?

TPO roofing is a durable single-ply membrane system consisting of three layers – a TPO polymer base, a polyester-reinforced scrim, and a TPO compounded top ply – introduced in the early 90s. It provides a reliable, watertight covering that can stand up to the elements and help protect the interior of a building.

TPO roofing is an excellent choice for many commercial and flat-roof residential buildings, as it is highly resistant to moderate UV radiation and extreme temperatures. It is also easy to install and maintain, making it a cost-effective solution for many roofing needs.

See TPO Roofing: Cost, Material, Repair & Installation Guide for the first version of this content.

Prevent catastrophic damages and injuries from a failed roofing system. Knowing how long different roofing systems are supposed to last will help you get it evaluated and replaced when the time is right.

atlantacommercialroofingcontractors.com gathered the following information to help you determine when your damaged or aging roofing system needs to be replaced.

What Impacts How Long a Roof Lasts?

Each type of roofing system has a projected lifespan. What determines a roofing system’s longevity includes:

• Bi-annual inspections (spring and fall) under a maintenance program
• Early detection of hidden problems/defects in the roofing system
• Material quality
• Installation quality (workmanship)
• Weather patterns (severe weather events like hail, tornadoes, hurricanes, etc.)

A well-installed roofing system with continuous maintenance, care, and eventual repairs can last from 20 to 100 years, depending on the roofing material. Consider the following roofing systems:

Composition Shingles 15 – 40 Years

Composition shingles are a composite product made from a fiberglass or cellulose mat, asphalt, and mineral granules. Composition shingle roofing systems are also environmentally friendly. Most composite roof materials are made with a paper backing and produced using recycled materials.

This durable roofing system can last an average of 15 to 20 years with minimal maintenance and care. When properly installed and maintained, this roofing system can last up to 40 years.

Signs that a composition shingle roof replacement may be necessary include:

• Visible signs of roof or shingle aging
• Multiple leaks
• Missing mineral granules
• Shingle curling (most common along edges)
• Missing shingles
• Moss growth on shingles
• Algae growth (dark stains running down the roof slope)

Severe weather events are common factors in roofing system damages and failures. After such events, your roofing system should be inspected and repaired if possible.

Note 1: A typically hidden problem with shingle roofing systems is bad shingle adhesion. Contributing factors often include manufacturing inconsistencies, poor installation practices, advanced aging and shingle deterioration, cold weather installations, lack of attic ventilation, and repeated thermal expansion and contraction.

Note 2: Another, often hidden, issue occurs when gaps or openings are left in a roofing system's eaves, soffit, or fascia. These openings allow small animals/wildlife to enter attic space, destroying insulation or compromising a roofing system's integrity from the inside out.

Asphalt Shingles 10 – 20 Years

Asphalt shingles are not made solely of asphalt. They consist of either a fiberglass or felt paper base coated with a waterproof layer of asphalt and topped with mineral or ceramic granules. Over the past four decades, fiberglass-based shingles have been the more requested product.

This roofing system can last an average of 10 to 15 years with minimal maintenance and care. When properly installed and maintained, this roofing system can last up to 20 years.

Similar to composition shingles, signs that an asphalt shingle roof replacement may be necessary include:

• Visible signs of roof or shingle aging
• Multiple leaks
• Missing mineral granules
• Shingle curling (most common along edges)
• Missing shingles
• Moss growth on shingles
• Algae growth (dark stains running down the roof slope)

Note: Shingle roofing systems often hide water damage from failed flashing in valleys, around chimneys, and in poorly constructed chimney crickets or saddles. This type of failure can lead to multiple leaks, deck rotting, and eventual roof failure.

Severe weather events are common factors in roofing system damages and failures. Again, after such events, your shingle roofing system should be inspected and repaired if possible.

Wood Shingles Up to 30 Years

Wood shake roofing and a wood shingle system are both typically made from cedar, cypress, redwood, or pine. While these wood products have similarities, they're produced differently. Wood shingles are usually machine cut on both sides, and wood shake material is created by splitting rectangles from a log.

Being rot and insect resistant, a wood shingle roofing system can last up to 30 years with diligent annual upkeep.

Signs that wood shingle or wood shake roof replacement may be necessary include:

• Visible signs of aging or damage in multiple areas of the roof
• Multiple leaks
• Cracking, splitting, or warping shingles
• Missing shingles

Often, these signs will be confined to a section of the roof, which may mean only a repair is needed.

Note: A commonly hidden problem with wood shingle roofing systems is a poorly ventilated attic. Moisture that cannot escape the attic is forced upward through the roof structure causing shingles to curl and buckle. This uneven warping traps water, exacerbating the roof's deformation and rapid decay of its framework.

Single-ply Membrane (TPO & PVC 15-30 Years, EPDM 30-50 Years)

Single-ply membrane roofing systems require fewer seams than asphalt roofing systems and don't require torches or hot asphalt for installation. Single-ply systems come with prefabricated finishing accessories that make installation easy. Consider the following:

TPO – TPO (thermoplastic polyolefin) is a single-ply membrane and is one of the fastest-growing commercial and residential roofing systems. TPO roofing systems are made of a single layer of synthetics and a reinforcing scrim used to cover flat roof substrates.

Because TPO is relatively new in the roofing industry, its full lifespan has yet to be determined. This roofing system can last an average of 15 to 20 years with minimal maintenance and care. When properly installed and maintained, this roofing system can last up to 30 years before replacement.

To learn the benefits, cost, and problems related to a TPO roofing system, read the TPO Roofing System Explained article.

Signs that a TPO roof replacement may be necessary include:

• Visible signs of aging or damage in multiple areas of the roof
• Multiple leaks
• Chronic ponding
• Severe alligatoring (shrinkage and cracking)

Note 1: Often overlooked and elusive are damages caused by a parapet wall's failed metal coping. This roofing system malfunction allows water to collect between the TPO membrane and roof substrate, ultimately resulting in leaks, membrane deterioration, and structural damages to the building.

Note 2: Another hidden problem for flat or low-sloped roofing systems occurs when internal drainage (drainage routed through the structure) becomes clogged. A blocked drainage system can lead to ponding and severe water damage requiring costly structural repairs and roofing system replacement.

Detected early, these issues can be halted with repairs. When the roofing system becomes compromised in multiple locations, replacement may be the only option.

PVC – PVC (polyvinyl chloride) roofing is a single-ply roofing system used on commercial, industrial, and residential flat or low-sloped roofs. PVC is among the world’s most widely produced synthetic plastic polymer.

Like TPO, this roofing system can last an average of 15 to 20 years with minimal maintenance and attention. When properly installed and maintained, a PVC roofing system can last up to 30 years before replacement.

Like TPO, signs that a PVC roof replacement may be necessary include:

• Visible signs of aging or damage in multiple areas of the roof
• Long tears or rips
• Multiple leaks
• Chronic ponding
• Severe alligatoring (shrinkage and cracking)

Note 1: Improperly welded or damaged seams can allow water infiltration, often remaining undetected until extensive damages have occurred to the roofing membrane and substrate, requiring the roofing system's replacement.

Note 2: Foot traffic to and from electrical equipment and other rooftop installations can result in membrane tears and roofing system damage that can also go undetected until such damages require extensive repairs or roofing system replacement. This type of damage can be prevented by installing reinforced walkways or paths wherever foot traffic may be required.

Detected early, these issues can be halted with repairs.

PVC is somewhat similar when compared to TPO, but there are some unique advantages and we suggest knowing The Difference Between PVC and TPO Roofing Systems.

EPDM – EPDM (ethylene propylene diene polymethylene) is a durable synthetic rubber roofing membrane produced using two primary ingredients, ethylene and propylene, derived from oil and natural gas.

Utilized worldwide in the roofing industry, EPDM membranes exhibit a high level of stability as they age. This roofing system can last an average of 30 years with minimal maintenance and care. However, when properly installed and maintained, an EPDM roofing system can last up to 50 years before requiring replacement.

Signs that an EPDM roof replacement may be necessary include:

• Visible signs of aging or damage in multiple areas of the roof
• Long tears or rips
• Multiple leaks
• Chronic ponding
• Severe alligatoring (shrinkage and cracking)
• Use of improper repair materials, including asphalt and roofing cements

Note: One of the more elusive complications for this and all other flat roofing systems is an incorrect slope (these roofing systems are often referred to as low-slope roofing systems). If the slope is too low, ponding can occur with heavy precipitation or even the slightest drainage obstruction. Ponding or water pooling leads to rapid deterioration of all roofing system components and will likely result in the need for a complete roofing system replacement.

To learn more of the benefits, installation process, cost, warranty, and problems with an EPDM roofing system, read EPDM Roofing System Explained.

Built-up Roofing (BUR) 30+ Years

Built-up roofing systems consist of multiple layers of asphalt alternated with felt sheets applied over the roof deck (substrate), vapor retarder, and insulation that is attached to the roof decking. The system is then covered with a reflective membrane (cap sheet) or coating system.

Depending on the climate and materials used, a built-up roofing system has an average lifespan of 20 years. Well-installed and maintained BUR systems have been known to last 30+ years.

Signs that a BUR roof replacement may be necessary include:

• Multiple leaks (especially after having been repaired)
• Chronic ponding
• Severe weather or impact damage

Note: Leaks occurring in a built-up roofing system are often elusive, remaining hidden until severe damage has occurred to the roofing system and building structure. When a layered roofing system such as this develops multiple leaks, the likely course of action is to replace the system entirely.

To learn more of the installation process, benefits, cost, warranty, and potential problems with a Built-up roofing system, read the Built-up Roofing System (BUR) Explained article.

Modified Bitumen (ModBit) 15 – 25 Years

Modified Bitumen (ModBit) roofing is an asphalt-based roofing system similar to Built-up-Roof (BUR) and is designed for structures with low-slope or flat roof structures. Its five layers of protection make this roofing system one of the most trusted in the industry today.

Location, maintenance, and roof design are influencing factors on this system’s longevity. This roofing system can last an average of 15 years with minimal maintenance and care. When properly installed and maintained, a ModBit system can last up to 25 years before needing replacement.

Very similar to BUR, signs that a ModBit roof replacement may be necessary include:

• Multiple leaks
• Chronic ponding
• Severe weather or impact damage

Note 1:When this or other flat roofing systems are ballasted with gravel or stone, repairs will often require the removal of that gravel or stone. This process may ultimately require the partial or complete replacement of the roofing system.

Note 2: A common and barely noticeable problem with ModBit roofing systems involves vibrations from mechanical equipment causing mechanical fasteners to loosen and back out, leaving holes in the membrane. As this condition progresses, severe water damage including rusted components, substrate or decking deterioration, leaks, and costly structural damages occur and can remain virtually unnoticed until a partial or total failure of the roofing system.

Note 3: Roof coatings are commonly applied to aging roofing systems to extend their lifespan. In doing so, a roof coating may fail, allowing slow leaks to develop and remain undetected until severe structural damages occur. These damages become evident as interior leaks, sagging areas in the roof, severe ponding, and roofing system failure if left to develop.

To learn more about the modified bitumen product, benefits, warranty, cost, and potential problems with this roofing system, see this Modified Bitumen Roofing System Explained article.

Metal Roofing Up to 70 Years

Metal or tin roofing is a popular roofing system around the United States and in Canada. The term “tin” is used interchangeably with metal, steel, or galvanized steel roofing. However, tin is an incredibly rare element and unused for roofing.

This incredibly durable roofing system can last an average of 25 to 40 years with minimal maintenance and care. When properly installed and maintained, a metal roofing system can last up to 70 years before requiring replacement.

Signs that a metal roof replacement may be necessary include:

• Multiple leaks
• Rusting components
• Multiple damaged panels
• extensive weather or impact damage

Note: Due to the expansion and contraction of metal roofing, fastening and anchoring systems can weaken and fail over time. This problem can result in complete roofing system failure and is often only detected during routine maintenance visits.

To learn whether this type of roof suits your needs, read Metal Roofing Advantages and Disadvantages.

Clay Tiles 50 – 75 Years

In use since the 17th century, clay tiles are made by baking molded clay. Tile density is determined by heating time and at what temperature. Known for their ability to withstand high winds, hail, and fire, these tiles are produced in white, yellow, orange, and brown shades.

A clay tile roofing system can last an average of 50 years. With proper installation and maintenance, a clay tile roofing system can reach 75 years before replacement is needed. In rare cases clay tile roofing can even reach a whopping 100 years.

Signs that a clay tile roof replacement may be necessary include:

• Multiple cracked, damaged, or missing tiles
• Roofing system sagging
• Severe weather or impact damage

Note: While clay tile roofing systems can be long-lived, flashing failures (corrosion or cracking), and fastener failures (rusting) often result in water damage to the roof's decking and multiple leaks in the structure below. This type of damage can remain dangerously elusive, only appearing during a maintenance inspection or when the roofing system partially or completely fails.

When damages are minimal or confined to a small area, clay tile roofing systems can be easily repaired. More extensive damages will likely require partial or full replacement.

Roofing Maintenance Program

Roof maintenance plans are provided by commercial and residential roofing contractors, in which they agree to perform scheduled inspections, cleaning, debris removal, and scheduled or recommended preventative roof maintenance.

Acquiring a roofing maintenance program from a licensed roofing contractor allows property owners to protect the roof’s warranty provisions, extend the roof’s lifespan, and ultimately save money by preventing significant damages and costly repairs.

Most roof warranties require a minimum of one roof inspection per year performed by an authorized contractor. These inspections allow early detection of problems and their timely repair before developing into catastrophic problems, leading to a roof’s replacement.

Commercial Roofing Maintenance Programs and Services can greatly extend the life expectancy of your roofing system. If you are beyond repair and in need of a new roof, consider starting a maintenance plan after its replacement; a preventative service will add years to the life of your roof, and considerable savings to your investment.

Commercial And Residential Roof Replacement

In this article, you discovered information about roofing system longevity to help you determine when your roof should be repaired or replaced.

When you know your roof’s projected lifespan, the durability of its materials, and have diligently provided for its care and maintenance, it is likely that your roof will far outlive its life expectancy.

Ignoring your roof and its maintenance needs will sharply abbreviate its lifespan, potentially leaving you with costly repair bills, significant leak damage, and in need of an emergency replacement when it suddenly fails.

Sources:
epdmroofs.org/what-is-epdm/
asphaltroofing.org/bur-multi-ply-built-up-roofing/
energy.gov/energysaver/design/energy-efficient-home-design/cool-roofs

See When Does a Roof Need To Be Replaced? for the first version of this content.

Avoid unexpected, expensive surprises when you replace your worn out commercial roof. By knowing the variable costs in a commercial roofing system replacement, you can ask the right questions to get a more accurate idea of the project cost.

atlantacommercialroofingcontractors.com gathered information about commercial roof replacement, what aspects of the project are variable in cost, what you can expect to spend on a new roofing system, and some of the available commercial roofing types.

Commercial Roofing System Replacement

The replacement of a commercial roofing system is a rare event for building owners and managers. When a roof is installed and maintained correctly, it can last for decades before needing replacement.

The following information will help you reach an informed decision about how to project roof replacement cost variables, and which type of roofing system to install:

Commercial Roof Accessibility

When replacing your commercial roof, access to your property and the roof can impact project costs as much as the roof type. Consider the following:

Commercial Building Height – Roof replacement for a 2-story commercial building will be much less costly than a 10-story commercial building. This is due, in part, to the need for cranes to remove old roofing material and lift new material to the work area.

Access to Building Property – Property access also has an impact on the project. The ability to freely move equipment to the property near the building will influence the logistics and project cost.

Material Storage Areas – Material storage is also a determining factor. Large “lay down” areas near the building facilitate the logistics of the roofing project and can lower its cost.

Building Occupant Safety – Building occupancy can pose a series of challenges to the roofing project. The safety and productivity of the building’s occupants must be considered at all times. If this requires roof replacement activities to occur after regular business hours, additional costs will likely be added to the project.

The easier it is to access your roof, execute the removal of the old roof, and install the new commercial roofing system, the less costly the project will be.

Commercial Roof Substrate Condition

Roof replacement costs can be heavily influenced by the condition of the substrate material. A commercial roof substrate may be composed of:

• A concrete, wood, or metal deck
• Plywood or cover board
• Insulation

Damages to the substrate must be repaired before roof replacement. This cost is a variable, as even the most experienced roofers with the best detection technology may not identify substrate damages until the old roofing materials are removed.

Local, Regional, and State Commercial Roofing Code Requirements

The location of your commercial building may make your roofing system subject to code requirements, including more robust fasteners at more frequent intervals, insulation, substrate, ventilation, and/or slope requirements.

An example of this would be commercial structures along the coast of Florida. Codes in these areas require commercial roofing systems to be designed to withstand higher wind loads. For these roofing systems, more durable fasteners at closer intervals would be required, increasing the cost of the roof replacement project.

Commercial Roof Load-Bearing Capacity

Another crucial factor in determining the cost of replacing your commercial roofing system is the calculation of its dead, live, and transient load capacity.

Calculating your roof load capacity is one of, if not the most crucial aspect when determining the construct of the roof’s substrate and selection of a roofing system. Your roof must be able to support its projected dead load (HVAC units, ducts, vents, exhaust units, etc.), live load (installers, repairmen, and technicians), and transient load (rain, wind, and snow).

Read more about commercial roof loads at atlantacommercialroofingcontractors.com/what-is-commercial-roof-load-why-you-need-to-know/

Commercial Roofing Types

No two roofs are the same. Thus, there are several commercial roofing systems to choose from. The following are some of the more popular commercial roofing types, installation information, and typical price range:

TPO, PVC, and EPDM Single-Ply Membrane Systems Can Cost from $3.50 to $8 per square foot

TPO, PVC, and EPDM are all known as single-ply roofing systems, they require fewer installation steps and are installed with a straightforward process:

• The old roofing system is removed
• The substrate is cleared of anything that may damage the selected membrane
• The membrane is rolled out onto the roof
• The membrane is then adhered to the roof using tape, glue, or heat (for thermoplastic material)
• The membrane is also adhered to itself where its edges overlap
• Protrusions are sealed

The time it takes to install a membrane, or single-ply roofing system also depends on the width of the membrane. The wider it is, the fewer seams there are to seal in the roofing system, which also leaves fewer opportunities for leaks and eventual substrate damage.

A BUR/Asphalt System Can Cost from $5 to $9 per square foot

Built-up roofing systems are among the oldest in modern times. BUR systems are durable and effective at resisting leaks while repelling water. The installation process occurs in the following steps:

• The old roofing system is removed
• Base sheets are laid down and attached to the roofing deck
• Felt is then glued to the base sheets using an adhesive, concrete, asphalt, or tar
• Gravel or cap sheets are installed over the felt
• A top layer of asphalt completes the installation

A BUR system creates a robust roof, able to keep severe weather and the elements from entering the building it protects.

A Metal Roofing System Can Cost from $5 to $14 per square foot

One of the most long-lived roofing options (forty + years), metal roofing is also one of the more expensive options. The following details how a metal roofing system is installed:

• The existing roof is removed
• The roof deck is built/prepped (framework and insulation installation)
• The flashing and eaves are installed
• Metal panels are laid out and fastened to the roof deck (fastening depends on which material the panels are composed of; aluminum, copper, steel, etc.)

Metal roofing comes in panels or steel shingles. Steel shingles are installed in the same manner as slate, clay, or concrete shingles.

A Modified Bitumen System Can Cost from $4 to $8 per square foot

Modified bitumen is a result of the evolution of asphalt roofing. It is a form of membrane flat roofing. The system is durable and can sustain substantial foot traffic without wear. The following is the installation processes of a “torch-down” modified bitumen roofing system:

• The existing roof is removed
• The substrate is cleared of any debris
• Heavy roofing felt is rolled out and nailed down
• Flashings and primer are installed
• The first sheet is rolled out along the edge of the roof for trimming and fitting
• The sheet is then rolled back up
• A torch is used to slightly melt the bitumen as the first sheet is rolled back out
• Overlapping sheets are then applied in the same manner until the roof is covered and sealed

Before selecting modified bitumen, verify that the existing substrate is compatible. Improper adhesion can lead to leaks and likely failure of the new modified bitumen system.

Disclaimer: The preceding price ranges are for comparative purposes only and should not be considered a part of any bid or quote for roofing installation, repair, or replacement.

Replacing Your Commercial Roofing System

In this article, you discovered information about replacing a commercial roofing system, the variables involved in calculating the cost, and commercial roofing types with their price ranges.

By knowing what to look for in a commercial roofing replacement estimate, you can avoid surprises by asking informed questions about installation variables.

When you choose to rely solely on a contractor’s bid or estimate, you may be in for a surprise when unforeseen damages and difficulties cause your roofing project to go quickly over budget.

Sources:
asphaltroofing.org/bur-multi-ply-built-up-roofing/
roofcalc.org/metal-roofing-prices/
nrc.gov/docs/ML1214/ML12146A122.pdf

See Commercial Roof Replacement for the first version of this content.

Don’t let the wrong roofing system or a poorly installed one cripple your business. Knowing what goes into installing or replacing a commercial roof will help you make informed decisions when it is time to act.

atlantacommercialroofingcontractors.com gathered information about commercial roof installation, replacement, and answers some common commercial roofing FAQs.

Commercial Roofing System Installation

Installing a roof on a new commercial building or replacing an old one may seem procedurally simple enough. However, some roofing system installation differences should be addressed.

TPO, PVC, and EPDM Membrane System Installation

Also known as single-ply roofing systems, these systems require fewer steps and are installed with a relatively straightforward process:

1. The roof is cleared of any material that may damage the membrane
2. The membrane is rolled out onto the roof (single-ply roofing material typically comes in rolls)
3. The membrane is then adhered to the roof using tape, glue, or heat (for thermoplastic material)
4. The membrane is also adhered to itself where its edges overlap
5. Protrusions are sealed

The time it takes to install a membrane or single-ply roofing system will also depend on the width of the material. The wider the material is, the fewer seams in the roofing system, which also translates to fewer opportunities for leaks and roof failure.

Elastomeric Coatings and Spray Polyurethane Foam (SPF) System Installation

Both Mesh Reinforced Elastomeric Coatings (MREC) and SPF coatng systems are intended to extend the life (up to 20 years) of an existing roofing system. Their installation includes:

Mesh Reinforced Elastomeric Coatings (MREC) – Composed of acrylic, elastomeric, and polyester reinforcing mats, MREC mats are applied in multiple layers until the desired thickness is reached.

Sprayed Polyurethane Foam (SPF) – SPF coatings may be acrylic, polyurethane, silicone, aggregate, or mineral granules. SPF coatings are sprayed onto a roof and should be applied by skilled workers.

• SPF can be applied directly to the roof deck or existing roofing system
• An SPF membrane is created by spraying a two-part liquid material onto the substrate
• The mixture expands and solidifies creating a waterproof polyurethane foam

Besides the protective nature of SPF coatings, the thickness and slope of the roof can be controlled during application.

BUR/Asphalt System Installation

Built-up roofing systems are among the oldest roofing processes in modern times. BUR systems are durable, they look nice, and are effective at resisting leaks and repelling water. The installation process occurs in four steps:

1. Base sheets are laid down and attached to the roofing deck
2. Felt is glued to the base sheets using adhesive, concrete, asphalt, or tar
3. Gravel or cap sheets are then installed over the felt
4. A final layer of asphalt completes the installation process

A properly installed BUR system creates a virtually impenetrable roof, able to keep severe weather and the elements from getting into the building it protects.

Modified Bitumen System Installation

Modified bitumen is an evolution of asphalt roofing that is a form of membrane flat roofing. The roofing system can sustain substantial foot traffic without wear. The following are the installation processes of torch-down and peel-and-stick modified bitumen roofing systems:

Torch-Down Modified Bitumen

1. The roof is cleared of debris
2. Heavy roofing felt is installed and nailed down
3. Flashing and primer are installed
4. The first sheet is rolled out along the edge of the roof (trimmed and fitted)
5. The sheet is rolled back up
6. A torch is used to slightly melt the bitumen as the sheet is rolled back out
7. Overlapping sheets are applied in the same manner until the roof is covered and sealed

Peel-and-Stick

1. The roof is cleared of debris
2. Heavy roofing felt is installed and nailed down
3. Flashing and primer are installed
4. The first sheet is rolled out along the edge of the roof (trimmed and fitted)
5. The sheet is rolled back up
6. The protective film is removed to expose the adhesive and rolled into place
7. Sheets are overlapped by about six inches until covering the entire roof
8. The system is pressed into place using a weighted roller
9. The roof edges are sealed with roofing cement and rolled again to seal the layers together

Before installing modified bitumen, verify that the existing material on the roof is compatible (previous systems using rubber can be eaten away, causing weaknesses and potential failure of the new modified bitumen system).

Metal Panel Roofing System Installation

One of the most durable roofing options (up to forty years), metal roofing is also one of the more expensive options. The following detail how a metal roofing system is installed:

1. The existing roof may need to be removed (depending on municipal codes and/or roof load capacity)
2. The roof deck is prepared (framework and insulation installation)
3. Flashing and eaves are installed
4. Metal panels are laid out and fastened to the roof (how they are fastened depends on which material the panels are composed of; aluminum, copper, steel, etc.)

Metal roofing can be installed using panels or steel shingles. Steel shingles are installed the same way as slate, clay, or concrete shingles.

New Commercial Building Roofing System Installation

A commercial building’s roof is its primary defense against damaging weather and natural hazards. Architects, builders, and building owners decide early in the designing stages which roofing system will be installed. Some of the factors that lead to a decision are:

• What equipment will be installed on the roof
• What is the needed roof load
• What type and how many protrusions will be needed (vents, exhaust pipes, skylights, drains, etc.)
• How and where will the roof shed water
• What is the expected foot traffic on the roof (walkways and reinforcements may be required)
• What is the anticipated lifespan of the roofing system
• Which commercial roofing system offers the best performance for future building activities (the roof used for an office building may not serve that used for a restaurant)
• Regional weather patterns (wind, rain, snow, hail, ice, and heat)
• Natural disasters (tornadoes, hurricanes, wildfires, earthquakes, etc.)

Many regions across the country experience one sort or another of natural disasters or recurring weather events. In many cases, these regions have developed laws or ordinances that require specific materials to be used when installing a new commercial roofing system.

Read more about what a commercial roof load is at atlantacommercialroofingcontractors.com/what-is-commercial-roof-load-why-you-need-to-know/

Replacing A Commercial Roofing System

For building managers, replacing a commercial roofing system is a rare event to see in one’s career. A well-installed and maintained roofing system can last decades before needing replacement.

When it comes time to replace the roof on your commercial building, the following steps will help you hire the right contractor to install the right roof for your building’s needs.

Bidding Process: Request bids from at least 3 contractors. By doing so, you can compare their prices, suggestions, more importantly, their work history, quality, and online reviews.

Roofing System Selection: The roofing system you select should accommodate the structure and purpose of your commercial building. An honest, professional roofer will help you determine which roofing system will serve your building best and advise you whether or not replacement is necessary.

Selecting a roofing system for your commercial building will require you to determine the best fit for your building, which system fits within your budget, which one offers the best protection and durability, and which maintenance program makes the most sense.

Roofing System Tear Off: If your current roof has reached the end of its life, it must be removed before installing a new one. This process exposes any flaws or defects in the roofing deck, which must be addressed before installing a new roof.

Roofing System Installation: Since every roofing installation is unique, a definitive installation timeline is difficult to project. The following should be taken into consideration when determining how long your installation will take:

• Roof deck repair (if required)
• The type of commercial roofing system
• The size of the roof (the larger the roof, the longer it will take)
• Unexpected weather events

Sometimes, when a permit is required to replace your roof, there may be stipulations that affect how and when the work can be done. To avoid delays, fines, and further punitive measures, permit requirements must be adhered to at all times.

Roofing System Guarantees, Warranties, and Maintenance Programs: Once your roofing system installation is complete, you should receive a:

• Guarantee covering the installation of your roof
• Warranty covering parts and materials
• Maintenance program proposal from your roofer to periodically perform inspections and minor repairs

Read more about what goes into a commercial roofing maintenance program at atlantacommercialroofingcontractors.com/maintenance-programs-services/

Commercial Roofing System FAQs

The following are answers to common FAQs based on general roofing information. Since no two commercial roofing systems are exactly alike, your specific situation may require further investigation for a more accurate response.

Question: How long will a commercial roofing system last?

Answer: A well-installed and maintained commercial roofing system can last from 30 years to the life of the structure it protects. The longevity of a roof depends mostly on the quality of its materials, installation, and maintenance program.

Question: My roof is leaking, what should I do?

Answer: Immediately contact your roofer. Whether you have a maintenance program or not, leaks must be addressed immediately to prevent structural damage to the roofing system and building.

Question: What is the difference between a commercial and residential roof?

Answer: Similar roofing systems can be applied to both commercial and residential structures. However, most commercial roofs will require a higher roof load to support HVAC and other equipment. They may appear very similar but are structurally different.

Read more about why you need to know your commercial roof load at atlantacommercialroofingcontractors.com/what-is-commercial-roof-load-why-you-need-to-know/

Commercial Roofing System Installation Process

In this article, you discovered information about new commercial building roof installation, commercial roofing replacement, and answers to common roofing questions.

By knowing what is involved in the commercial roofing installation or replacement process, you can make informed decisions when it’s time to select a roofing contractor and the best roofing system for your commercial building.

Not knowing what to do when you need a new roof can lead to the wrong roof installed, possible municipal code violations, expensive fines, and continuous roofing maintenance problems.

Sources:
wbdg.org/guides-specifications/building-envelope-design-guide/roofing-systems
buildings.com/article-details/articleid/4937/title/the-basics-of-roof-maintenance
asphaltroofing.org/bur-multi-ply-built-up-roofing/
whysprayfoam.org/spray-foam/roofing-systems/
amtrustfinancial.com/getmedia/7d774cf7-d8f4-455f-8b0d-a0d03a1c23fb/IBHS-Commercial-Roof-Best-Practices-Guide.pdf

See Commercial Roof Installation for the first version of this content.

Don’t let wet spots on your ceiling or streaks down your wall make your property look ugly and worth less money. Your leaky roof is often times the result of a failure in the roofing system’s flashing.

Without sufficient flashing, a roofing system cannot repel the elements, will ultimately fail and begin to leak. When installing a new roof or repairing a current one, it is essential that the flashing be compatible with the roofing system and be installed properly.

atlantacommercialroofingcontractors.com examines the purpose, types, and application of flashing used in commercial roofing systems.

What Is Flashing?

Flashing is a layer of waterproof material that keeps water from penetrating your roofing system at joints, vents, exhausts or appliance connection points. While caulk is used to fill small gaps around doors and windows, it has an entirely different purpose, and shouldn’t be confused with flashing.

Water naturally runs downhill to the lowest point of gravity. For flashing to work correctly, all seams must be installed facing downhill. Properly installed, the upper edge of flashing should be covered or protected by tarpaper, TPO, or whichever membrane or material is used in the roofing system.

Flashing Material

Numerous materials can be applied as flashing. The two criteria commonly used when determining which material to use are:

1 – The material won’t degrade from being in contact with other incompatible material.

2 – The material is impermeable to water.

The following materials are commonly used as flashing in both commercial and residential roofing systems:

Plastic and Rubber – While primarily used as caulk, plastic and rubber are excellent water-repellants when applied as flashing.

PVC and TPO – Both PVC and TPO are popular types of roofing systems, and the same material can be used as incredibly effective and durable flashing.

Roofing Felt – Asphalt-saturated roofing felt can be used as flashing, but is not as durable as other options.

Aluminum – Durable, easy to form, and somewhat inexpensive. When left in contact with alkaline material like concrete, or treated lumber, aluminum flashing will corrode.

Galvanized Steel – Not as durable as other options, but it is very inexpensive.

Copper and Lead-Coated Copper – More difficult to bend and form than aluminum, but much more durable. Copper flashing is typically used during the installation of solar panel piping, wiring and sensor connections.

Lead – Because of its super-flexibility and durability, lead is a popular choice in the roofing industry (a favorite of masons for chimney flashing). There are potential health risks, but the use of lead flashing continues, and when properly installed can last for up to 200 years.

While most flashing is sold in rolls that vary in thicknesses and can be cut, bent, and shaped at the job site. Pre-molded flashings are also available for standard-sized exhaust pipes, vents, and fittings.

Flashing Types for Roofing Systems

The following are the names and descriptions of different types of flashing used in commercial and residential roofing systems:

Ridge Flashing – This flashing is applied at the “peak” of a dually sloped roof.

Bargeboard – This is the flashing along sloped roof edges.

Wall Abutment – This is where roof edges meet walls.

Corner Flashing – This flashing is used where walls meet, and it runs from roof to floor.

Inverted Corner Flashing – This flashing is used when the corner of a structure meets a wall. Instead of wrapping around the corner as in “corner flashing,” it is applied to the structure and the wall in an “inverted corner” from roof to floor.

Eaves Flashing – This flashing runs along the length of flat edges of a roofing system.

Drip Cill Flashing – This is the flashing which runs along the lower perimeter (at the foundation).

Valley Flashing – The point where two downward slopes meet is where valley flashing is applied.

Step Flashing – Commonly used in place of wall abutments or chimney and skylight flashing (on slopes), step flashing is the downward overlapping alternate layering of roofing and flashing material.

Metal Edge Flashing – Also known as “drip edge flashing,” this is installed around the perimeter of a roofing system to direct the flow of water off of it without entering the structure . To learn more about commercial edge flashing and coping visit disastersafety.org/ibhs/commercial-roofs-flashing-coping/

Saddle Flashing – This is the flashing used where joists meet walls or other support structures, wrapping around connection points to form a water-tight seal.

Vent Pipe/Exhaust Flashing – This flashing provides a water-tight seal at the point where vent or exhaust pipes protrude through a roof.

Cap Flashing – This flashing is usually composed of metal and is used to shield the upper edges of membrane base flashing along the top of a wall or column.

As you can see, flashing is a critical element in a roofing system. There are a few more essential components that comprise a complete roofing system. To learn these, and for more commercial roofing information and tips, visit atlantacommercialroofingcontractors.com/info/

Roof Flashing Weatherproofs Your Structure

Don’t let your building unnecessarily look run-down and develop water damage from preventable water infiltration and leaks. Keeping the elements outside is what a successful roofing system does, and it dramatically relies on properly applied flashing.

In this article, you discovered what roofing system flashing is, what it is used for, the different types, and its application.

The use of the wrong flashing material on a roofing system may lead to leaks and its ultimate failure. Save money and avoid unexpected interruptions of your business by having the appropriate flashing material properly installed in your commercial roofing system.

Sources:
http://web.mit.edu/parmstr/Public/NRCan/CanBldgDigests/cbd069_e.html
https://www.nachi.org/flashing-part1-12.htm

See Types and Purpose of Commercial Roof Flashing for the first version of this content.