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What Is Modified Bituminous Membrane Roofing

The Benefits Of A Self

Modified Bitumen Roofing Systems

Facing labor shortages and the need to maximize profit, commercial roofers have had to find new ways to move efficiently from one project to the next. Traditional low-slope roofing methods utilizing mopped asphalt or torch welding come with application constraints and safety considerations that can increase time spent on a jobsite and create challenges for workers, resulting in increased contractor insurance costs. Traditional installation methods can also generate fumes that cause discomfort for clients.

Evolving with market demands, self-adhered SBS modified bitumen roofing systems offer roofers a safe, clean and quick alternative to those installed by traditional methods. When installed properly, self-adhered systems can deliver the protection of those applied with hot asphalt or cold adhesive for a fraction of the labor or time, all without the mess, fumes, hassle or additional safety risks. Available with a variety of base sheet options, cool roof surfacing, impact resistance, uplift resistance and fire retardance, self-adhered products are versatile enough to accommodate nearly any residential or commercial low-slope roofing project.

App Vs Sbs Modified Bitumen

Compared to SBS-modified bitumen , the APP-modified bitumen membrane has a much higher melting point. APP also is much more UV-resistant, making it much less likely to crack or damage than SBS. Because of this, APP is the best option for flat roofs in dry and hot climates, such as Southern California.

Spray Polyurethane Foam Roof Systems

SPF roofs are built up in two components. First, a layer of foam is applied to the substrate. Second, a topping coat is added to protect the foam layer and create a watertight barrier.

Diagram of a Spray Polyurethane Foam Roof System

The base layer is a two-part foam made from isocyanate and polyol resins that get combined at the spray gun to create a rigid, closed-cell polyurethane foam insulation. The foam is applied at various thicknesses to provide the proper R-value and to slope the roof toward drains. The substrate must be clean and dry to ensure proper adhesion.

The protection layer is spray applied, but roller application is also possible. There are a few coating options depending on the situation: acrylic, silicone, butyl rubber, or one of many urethanes. The key is that the coating is elastomeric so it is flexible, which ensures longevity under varying wether conditions. Sand or other very small aggregates are applied to the wet coating to add durability and slip-resistance to the finished product.

Since the products are mixed on-site, it is important for the contractor to monitor the weather conditions during installation. Calm and dry conditions are required since wind and moisture can affect the spray application quality. Manufacturers have different formulations that are used depending on the temperature during installation.

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Advantages Of Bitumen Membranes For Commercial Roofs

There are some great reasons to opt for a bitumen membrane for your flat or low-sloped commercial roof.

  • Theyre tear- and puncture-resistant. Due to the elasticized nature of bitumen material, it takes a lot to damage it.
  • Theyre energy efficient. Many bitumen membranes can be treated to add cool roof features like light and heat reflectance. This, in turn, can drive down heating costs during those sweltering Colorado summers.
  • Theyrea cinch to repair. Thanks to the easy availability and simple installation of bitumen patches, damaged sections can be quickly restored.
  • Theyre highly flexible. As the weather in Colorado turns from cold to hot and back again, building materials expand and contract. This can place a stress load on the roof, and a bitumen membrane does a great job of accommodating this stress through enhanced flexibility.
  • Theyre incredibly waterproof. Of all of the available commercial roofing systems out there, bitumen membranes outperform when it comes to protection from water ingress.
  • As you can see, bitumen membranes are an excellent choice for commercial property owners who want decades-long protection from the elements at a price that wont break the bank.

    Remember that it matters who installs your bitumen membrane! A-to-Z Roofing & Exteriors specializes in the expert installation of all forms of commercial roofing materials, including bitumen membranes, TPO, EPDM, and others.

    Highly Durable In High Traffic Areas

    Modified Bitumen Roofing

    If your low slope roof gets a lot of traffic, modified bitumen should be on your short list of membranes. Because it is a more traditional roof membrane applied in multiple layers, it stands up to foot traffic very well. While no roof membrane should serve as a patio or a work platform, the reality is people often treat flat roofs like a deck. With a granulated cap sheet, modified has a better chance of standing up to foot traffic than other systems.

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    What Is Modified Bitumen Roof + Pros & Cons

    Disclaimer | This article may contain affiliate links, this means that at no cost to you, we may receive a small commission for qualifying purchases.

    Flat roofs have been around for a very long time, and theyve held the spotlight for being the go-to option for commercial roofs. They were always a popular preference for commercial buildings, and now they are also gaining momentum for residential ones. One of the most preferred roofing choice for flat roofs has been Modified Bitumen.


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    What Is The Difference Between Built

    A modified bitumen roof is asphalt-based and consists of multiple protection layers. It is meant for low-sloping roofs. Typically, the bitumen within the roofing membrane has modifications comprised of polymers. And it also contains polyester or fiberglass reinforcement fabric.

    Some people confuse it with a built-up roof , sometimes referred to as tar and gravel roofs. After all, it is also asphalt-based and designed for low-slope and flat roofs. And the latter kind of roofing consists of multiple asphalt layers that alternate with ply sheets or reinforcement fabric. But these two roofing systems differ in some ways.

    Application Methods For Modified Bitumen Roof

    Torch Applied Modified Bitumen Membrane Roofing Installation

    There are different types of Modified Bitumen roofing systems to install. Below we are going to read about the two different types of installation of Modified Bitumen roofing. Two types of Bitumen roofing installation are: Torch-Down installation method and a peel and stick installation method.

    Tools used in the installation of Modified Bitumen Roofing

    • Measuring tape

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    What Is A Modified Bitumen Roof

    Modified bitumen, also known as ModBit, is more common on residential roofs but is also used on commercial roofs. Although it has a lot of advantages, it isnt for everyone. Continue reading to learn what a modified bitumen roof is, how long it lasts, how much it costs, the benefits of a modified bitumen roof, and more.

    Bitumen Roofing: Sbs And App

    Our roofing materials are certified by FM Global. Most of SOPREMAs bitumen roof membranes are SBS membranes, and we also offer APP roofing systems. SBS membranes consist of styrene butadiene polymer resins modified with synthetic rubber and APP are modified with plastic in the form of atactic polypropylene.

    More free-flowing, so even easier to apply
    Takes less heat to install. It can even be installed with cold adhesivesMelts into a liquid wax when torch-applied, so requires more heat to install
    Withstands the challenges of hot and cold climates year after year, as well as building movementSomewhat less flexible than SBS bitumen

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    How Long Does A Modified Bitumen Last

    Modified Bitumen Roof System can last for 10-20 years. Which is less time in comparison to another roofing system. The amount of time Modified Bitumen roofing lasts depends on many things.

    Like the materials used, if the system is installed properly or not, if it is checked frequently and if there is any issue repair should be done properly, and maintained well.

    Weight And Thickness Of Modified Bitumen Roofs

    Global Roofing Group

    Individual sheets of modified bitumen are typically between 120 mils and 180 mils thick.

    A typical sheet of modified bitumen roofing weighs about 1.1 lbs. per square foot.

    The vast majority of installed mod bit roof membranes have two plies, a base sheet and a cap sheet. So the average modified bitumen roof membrane is about 300 mils thick and weighs around 2.2 pounds per square foot.

    Rolls of modified bitumen roofing placed for quick access during a torch-down roof installation.

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    What Are The Benefits Of Modified Bitumen Roofing

  • Tear-resistance. Modified bitumen offers outstanding durability and tensile strength, making it resistant to tears from weathering, debris, and even consistent foot traffic.
  • Waterproof. When properly installed, modified bitumen provides some of the best waterproofing protection of any roofing material on the market. Redundant layers enhance this quality even further.
  • Ease of installation, repair, and maintenance. Modified bitumen is easy to maintain, and if it does tear or leak, it can be easily patched.
  • Flexibility. Modified bitumen expands and contracts with changing weather conditions without losing integrity.
  • Energy-efficient. Certain types of modified bitumen offer high UV resistance and reflect the suns rays for lower energy bills.
  • What Is A Membrane Roof

    Membrane Roofing is a roof system that creates a continuous watertight covering to protect the interior of a building. Membrane roofs are predominately used as a flat roofing system since they are watertight, which is critical where water is not shed immediately. They can also be used on very low pitched roofs where shingled, slate, or tiled roofing would not perform.


    A variety of materials can be used to construct membrane roofs, for example synthetic rubber, thermoplastic , liquid polyurethane, or modified bitumen can all be used. However, the essentials of a membrane roof include weatherproofing components, reinforcement, and surfacing. Sometimes a single material performs multiple essential tasks.

    Below the main roofing layers are the substructure , insulation, plywood, underlays, vapor barriers, etc.

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    Can You Repair A Modified Bitumen Roof

    Generally, MBRs do not need a lot of maintenance one performs the installation correctly. However, if an issue arises, you can repair the modified bitumen roofing to increase its lifespan.

    For APP versions, repairs usually consist of heat welding of the seams to take care of any seam failures. Also, you may need to apply a coating to safeguard this form of MBR from degradation caused by prolonged exposure to the sun.

    On the other hand, SBS versions also require applying a protective coating to safeguard it from prolonged exposure to sunshine. In addition, you may need to hold weld the seams to deal with seam failures. Also, you may need to patch up the roof when issues such as cracks develop and blisters develop.

    Work With Reliable Roofing

    Hot Applied Modified Bitumen Roofing System — Application Excellence

    When you are considering a modified bitumen roofing system for its many advantages, consult Reliable Roofing for premium roof replacement services. Our knowledgeable commercial roofers will help you decide if a modified bitumen roofing membrane will meet your buildings needs.

    While a modified bitumen roofing system is an ideal roofing option, facility managers should be aware that components can also be used for repairs on existing built-up roofs. Our experienced roofing contractors will ensure the product is installed correctly and efficiently.

    A critical part of installing this roofing system is the insulation. Reliable Roofing crews ensure adequate insulation is installed so that the modified bitumen roofing system performs optimally. We also follow all manufacturers instructions so that your building remains protected from leaks and damage.

    Roofers at Reliable Roofing excel at roof repairs, maintenance, inspections and replacement. While servicing roofs is our primary service, we are also equipped to install roof equipment, such as flashing, HVAC equipment and exhaust fans. We facilitate waterproofing or sealing various equipment.

    When you aim to install, maintain or inspect a modified bitumen roofing system, count on Reliable Roofing for our expertise, superior knowledge of roofing products and quality workmanship. We are proud to successfully serve commercial businesses in and around Chicago, Illinois.

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    History Of Modified Bitumen

    Modified bitumen first appeared in commercial roofing in the mid-1960s in Europe. Before that time, the conventional roofing system used on most commercial structures was built-up roofing , a complicated system of alternating layers of asphalt and fabric with a top layer of gravel.

    While BUR was a tried-and-true method, it was heavy, costly to install, difficult to repair, and often had trouble holding up against extreme temperatures. By integrating the bitumen with polymers and fiberglass into a simple membrane, the developers of modified bitumen hoped to simplify the roofing process while resolving some of the most common issues with BUR.

    Overall, the efforts were successful. Modified bitumen proved to be easier to install while providing enhanced protection compared to BUR systems, even in very cold temperatures. By 1975, modified bitumen was in wide use here in the United States, and today, it has all but replaced BUR as one of the most reliable roofing materials on the market.

    The Advantages Of Sbs Bitumen

    1. Exceptional lifespan

    SOPREMAs SBS bitumen membranes have a tested life expectancy of over 30 years. With a multi-layer bituminous roofing membrane system, a reliable and robust waterproofing solution can optimise longevity for the building. Bitumen roofing requires little upkeep over the years, although annual maintenance is recommended to extend its lifespan.

    2. Versatility and sustainability

    Bituminous roofing membranes are not just for flat roofs, but can also be applied to barrel and dome roofs, ballasted and complex profile roofs, and guarantees a seamless finish for upstands and complex detailing. Bituminous membranes are also available for green roof applications. Root resistant bituminous roofing membranes, such as SOPRALENE Flam Garden 250 AF, can be used for green roofs as they stop the roots from penetrating the waterproofing system.

    3. Ideal for refurbishment projects

    Bituminous roofing membranes are perfectly suited to refurbishment projects where existing bituminous or asphalt systems have exceeded the performance lifespan of the existing waterproofing system.

    For more information contact .

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    There Are Two Main Types Of Modified Bitumen Sheets: Sbs And App

    APP. This stands for Atactic Polypropylene, and is a thermoplastic that is placed in the asphalt to reflect UV rays while protecting against colder temperatures.

    SBS. This stands for Styrene-Butadiene-Styrene, which is a rubber polymer mixed with asphalt. SBS is more akin to BUR systems.

    APP has qualities of todays modern thermoplastic systems. The differences between APP and SBS are beyond the scope of this blog.

    Pros And Cons Of Modified Bitumen Roofing

    Modified Bitumen Roof Installation Minneapolis MN ...

    By Reliable Roofing

    Modified bitumen roofing, being asphalt-based, is designed for low slope roofs. Mod-bit has been successfully used in the United States for over 40 years. Its unique properties give it many of the benefits of old-fashioned built-up roofing and some of the convenience of todays single-ply roofing systems. If you are re-roofing a flat roof, mod-bit should be on your list of options.

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    What Is A Bitumen Membrane

    Bitumen membranes are popular for the protection of flat or low-slope roofs, especially for commercial buildings with large square footages.

    This method of waterproofing and shielding the roof has been around for decades, but some recent advancements in material technology have yielded even stronger, more resilient roofs that can last for as long as 20 years or more. This is great news for commercial property owners in Colorado!

    In this article, the roofing experts at A-to-Z Roofing and Exteriors are diving deep into the fundamentals of bitumen membranes as theyre used on commercial roofs. Well be discussing what exactly these membranes are, how theyre applied, and what the pros and cons are.

    Lets get started!

    Types Of Roof Membranes For Flat Or Low

    Materials & Systems> Thermal & Moisture Protection

    Flat roof membranes are used in both residential and commercial roofing projects. In residential, it is used predominantly for large apartment buildings, garage roofs, and small extensions. It is also increasingly used for larger main roofs in single-family housing with modern designs that integrate flat roofs.

    Most large commercial projects such as apartments, warehouses, sports facilities, schools, and hotels utilize membrane roofing on flat roofs. Most of these commercial buildings require roof access for mechanical systems or they have occupied roof terraces, making membrane roofs an ideal cost effective solution.

    The two most common types of flat roof membranes are EPDM and PVC. While modified bitumen is also still used, most owners are moving away from asphalt based products due to the environmental and health hazards.

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    What Are Modified Bitumen Membranes

    Modified bitumen membranes are made by combining bitumen and styrene-butadiene-styrene a family of synthetic rubber originating from styrene and butadiene. This process modifies the bitumen to create a copolymer with vastly improved elasticity, tensile strength, abrasion resistance, ageing stability and a higher softening point whilst retaining the phenomenal waterproofing performance of bitumen. The SBS modified bitumen is integrated with reinforcing mats consisting of polyester, fibreglass, or a composite of the two, to form the finished membrane

    Modified bituminous systems utilise two layers of factory manufactured SBS modified bitumen sheet material. Firstly, an underlayment is applied to your roofing structure, followed by a cap sheet with a mineral slate finishing for added UV protection and an improved aesthetic finish.

    These are available for either torch-on or self-adhesive roofing application. The resulting system provides multiple layers of high-performance waterproofing protection.

    App Modified Bitumen Roofing Systems

    Installing Self-Adhering Modified Bitumen System Garland Roofing

    Count on IKO for the best in APP modified bitumen roofing systems. IKO APP Modified Bitumen Roofing Systems are asphalt based and constructed of a tough non-woven reinforced polyester mat strengthened with select glass fiber strands treated with Atactic Polypropylene polymers to impart plastic type qualities. IKO Armourplast Classic and Armourplast Granular APP modified bitumen membranes may be used as either a cap sheet or a base sheet, depending on the application.

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