What is a Self-Adhesive Roofing Membrane
Self-adhesive roofing membranes are highly versatile and applicable across a wide range of roofing needs. They are among the most versatile roofing products commonly used today. These membranes are available in types suitable for both low-slope and steep-slope roofs, as well as asphaltic and non-asphaltic membrane/system designs. While the adhesives used in self-adhesive membranes are most commonly asphalt-based, non-asphaltic options, such as butyl, are also available.
Polyglass manufactures and offers a broad range of self-adhesive membrane products, designed to meet nearly any roofing system or wall condition, providing effective waterproofing and weatherproofing solutions for various construction applications.
As the name suggests, self-adhesive membranes simplify the application process. Installation is straightforward—simply remove the release film and apply the adhesive side to the surface. This method eliminates the need for open-flame torches, smoky asphalt kettles, or odor-producing adhesives, resulting in faster installation and a safer application process. Self-adhesive membranes bond well to almost all substrates that are clean and properly prepared. The bond of Polyglass SA membranes is established upon installation and continues to strengthen over time as the membrane remains in service.
Also Read: [Video] How to install ADESO® Self-Adhered Membranes
What are the typical uses for Self-Adhesive Roofing Membranes
Steep-Slope Roof Applications
When discussing options for steep-slope roof coverings, the usual candidates enter the discussion:
- Asphaltic Shingles
- Concrete Roof Tile
- Clay Roof Tile
- Metal Panels & Stamped Metal Pieces (mimicking tile or shakes)
- Wood Shakes & Shingles
- Composites
Even the best and most expensive roof coverings are designed to shed water and require an underlayment. While building codes may only require a lightweight, organic, loose-laid felt that is fastened to the deck, these underlayments provide very limited, or no, weather protection should the roof covering be lost due to wind or other storm events. The roof covering helps to shed surface water, as does the roof underlayment, but if the roof covering is lost, the underlayment is often lost as well, offering no protection to keep water from entering the structure.
However, self-adhesive membranes bond directly to the deck, serving as a secondary water barrier for any roof covering system. These membranes provide a fully bonded layer of protection and are impermeable; once properly lapped, neither liquid water nor water vapor can penetrate a self-adhesive underlayment. Except for a few limited roof covering types, such as seamed and rolled metal panels, all other steep-slope products overlap and function as water-shedding systems. This is why all steep-slope systems have specific minimum slope requirements; if these are not met, the system will not perform properly and will not meet Building Code standards.
Areas around chimneys, vents, skylights, and roof edges are also vulnerable to leaks. In these locations, it is especially important to use an underlayment that can tie the details together and perform in a watertight manner.
Another important consideration is that underlayments must be fastened to the deck with thousands of nails, which put holes through the underlayment membrane. A self-adhered membrane bonds directly to the substrate and only requires back-nailing at the overlaps, ensuring that all fasteners are hidden and covered by a second layer. Even in applications that require fasteners to be exposed and penetrate the underlayment, a self-adhesive underlayment seals around the penetrating fasteners. In fact, this sealing is part of the test standard (ASTM D 1970) to ensure that fasteners do not leak.
Low-Roof Applications
When discussing options for self-adhesive low-slope roof coverings, these are less commonly known by the average consumer, so a more in-depth discussion is needed. However, the most commonly used options include:
- Asphaltic Modified Bitumen Membrane (APP and SBS)
- Thermoplastic Polyolefin (TPO)
- PVC
- EPDM (vulcanized rubber)
The common perception when discussing low-sloped roof types is often that it is an “out of sight, out of mind” issue. Rarely does the average person look at a low-slope building design and think, “I wonder what type of roof is on that building?”
Historically, low-sloped roofs have been thought of as “commercial” roof products, and to some extent, this is accurate. Whether the low-sloped roof is on a house or a commercial building, the basic membranes are the same. It is commonly believed that these roofs require smelly asphalt kettles, high BTU open-flame torches, or solvent-based adhesives for installation.
Also Read: Steep-Slope and Low-Slope Roofs – What You Should Know
Challenges and Solutions; Self-Adhesive is the Answer
All roofing products present unique challenges, some of which are easier to overcome, while others are more difficult to address.
Open Flame Torches or Heat-Welding
Many asphaltic membranes, such as APP-modified bitumen, are designed for heavy-duty services and more challenging application scenarios. In these situations, an APP-modified bitumen system is a common and well-suited choice. However, in wood deck applications, the increased fire risk must be a top priority. For these conditions, self-adhesive APP-modified bitumen membranes can be the ideal solution. Offering the redundancy of a multi-ply roof and the superior exposure weathering of APP-modified asphalt, it may be the best option for these applications.
Hot Asphalt and Solvent Odor and Equipment complications
When considering a cold-adhesive system or adhesive-bonded membrane, there are unique challenges that must be addressed first. For larger projects, adhesives for most roof types are typically applied using high-pressure equipment, which can introduce noise and increase the risk of equipment breakdown. Once dispensed on the roof, the question arises: how much solvent or other adhesive odor is tolerable to workers, building occupants, and the surrounding public? Rooftop mechanical systems bring in outside air as part of their operation, which can also bring solvent odors into the building.
Numerous systems utilize hot asphalt, which requires large, bulky kettles that occupy valuable building space and pose an exposure risk to the surrounding public. Like solvent odors, those from hot asphalt can also enter the building, creating a noxious smell for occupants.
Self-adhesive systems, on the other hand, have the adhesive already integrated into the self-adhered membranes, eliminating the need to prepare and apply it separately. There is no mixing, applying, or waiting for the adhesive to reach the right tackiness or cure level before proceeding. The membrane is ready to use as soon as the backing is peeled off. The factory-applied adhesive is evenly and optimally distributed, which eliminates inconsistencies in thickness and coverage that often occur with manually applied adhesives. The use of fewer materials allows the work to be completed faster and cleaner, with less site debris.
Less Project Equipment
With the simplicity of primary and secondary materials, the entire process requires less loading and storage equipment, resulting in a less cluttered project site. Loading materials onto the rooftop becomes a simplified, one-step process. Rolls can be easily transported to the roof by crane, conveyor, or other equipment capable of moving rolls from the ground or delivery truck to the rooftop.
This streamlined process also reduces the need for equipment such as nail guns, compressors, torches, propane tanks, and other tools typically used in other membrane applications. Not only does this speed up the job, but it also enhances safety and reduces clutter, which is particularly beneficial on complex or steep roofs.
Seams and Laps are Simplified
The seams and laps of self-adhesive membranes are simplified. To install, ensure the membranes are laid straight with the proper overlapping width, then simply apply pressure. In some cases, flameless heat may be used.
Self-adhered membranes are designed with precise edge areas that have enhanced adhesive properties. When one roll overlaps another, these areas align to automatically create a tight seal. The factory-applied, consistent adhesion ensures there are no weak spots along the seams, which is often a concern with manually applied adhesives where inconsistency can result in leaks.
Once the protective backing is peeled off and the membrane is pressed down, the adhesive activates and forms a waterproof bond. There is no curing or drying time required, and the seal begins protecting from moisture immediately.
Reduced Waste Management
Traditional roofing systems inevitably generate significant amounts of cutting and trimming, resulting in membrane pieces that cannot be repurposed. Additionally, traditional systems often require many secondary materials, such as adhesives in pails and hot asphalt packing. In contrast, most self-adhered membranes come in rolls with minimal packaging, reducing the amount of waste. Simply put, there is less waste to dispose of at the job site.
Using self-adhesive membranes also eliminates the risk of adhesive spills or drips that can occur with manually applied options. Cleanup not only wastes time but also requires the use of industrial-grade absorbents or cleaning solvents. Since self-adhered membranes are easy to cut and fit to the roof’s shape, there is less scrap and offcuts left over. In fact, most cut-offs can be reused for patches or other flashing conditions.
Importance of Choosing a High-Performing Roof
This discussion has explored a variety of roofing choices and types for both steep-slope and low-slope roof designs. In doing so, we are reminded of the complications often associated with many traditional roofing options. In nearly every scenario, self-adhesive roof membranes offer a viable alternative to other systems. Additionally, self-adhesive systems provide a simplified application, with the potential for reduced labor and waste, making them a sustainable choice.
The use of self-adhesive roofing systems does not diminish the essential qualities we expect from our roofing options; rather, it adds a level of ease and simplicity. Self-adhesive systems offer high-performance products, and when considering modified bitumen self-adhesive products, they provide value that traditional systems cannot match.
Building codes establish minimum standards for systems and processes, and manufacturers are increasingly emphasizing the importance of using at least code-compliant materials and systems. In the State of Florida, the building code requires roofs in hurricane-prone areas to have a secondary water barrier, which means using a self-adhesive membrane over the entire deck or, at a minimum, on all joints in the wood decking. In the State of California, the building code mandates that roofs in areas with a high wildfire risk must include an underlayment to help achieve a Class A roof covering rating.
In higher climate zones across the U.S., building codes also require an ice barrier consisting of at least two layers of underlayment cemented together, or a self-adhering membrane sheet, in regions where the January average temperature is 25°F (-4°C) or lower.
Polyglass’ patented ADESO® self-adhered technology checks all these boxes. It combines two distinct layers of compounds in a single membrane: an aggressive self-adhesive on the bottom layer to form a strong bond that prevents water infiltration and ensures the membrane stays fixed in place over time; and a cutting-edge modified bitumen compound on the top layer designed to withstand UV rays, resist tearing, and handle the thermal expansion and contraction caused by temperature changes.
Polyglass’ ADESO membranes are engineered to offer superior durability and reliability compared to traditional membranes, where a single compound rarely performs both functions as effectively. Contact us to learn more about the ADESO product range and discover the most advanced self-adhered underlayment for your next project.