A low-slope roof embodies minimal incline, lacking steepness and is defined by the Building Code. As defined, any roof having a slope below 2:12 falls into the low-slope category. To fortify these roofs against water damage, precisely designed protective systems are essential.
Products and Technologies for Low-Slope Roofs
Low-slope roofs rely on a variety of products and technologies to achieve optimal performance and longevity. Among the most common are multi-ply roofing systems and single-ply systems. The two most common types of multi-ply systems are Built-Up Roofing (BUR) membranes and Modified Built-Up Bitumen Membrane Roofing (MBUR).
Single-Ply Roofing Systems for Low-Slope Roofs
Single-ply roofing systems may consist of a single layer of a flexible membrane rolled out over the roof’s surface and seamed together. The three primary types of single-ply membranes used in low-slope roofing are:
Thermoplastic Polyolefin (TPO): TPO membranes can offer lightweight and cost-effective solutions but may experience stiffness issues and reduced performance in elevated temperatures. Due to significant formulation changes, these products have had challenges with their long-term weathering characteristics.
Ethylene Propylene Diene Monomer (EPDM): EPDM membranes, may offer advantages in colder climate zones where its dark color is advantageous where roof drying is imperative but can have limitations regarding chemical compatibility to many common construction materials and external flame resistance.
Polyvinyl Chloride (PVC): PVC membranes are a flexible plastic co-copolymer. Similar to TPO systems they can offer lightweight systems, however come at a higher installed cost than comparable TPO systems offering a premium product to TPO. This product category can come with temperature constraints for optimal performance.
What Challenges are Associated with Single-Ply Roofing Systems?
Despite being a favorable choice for low-slope roofs, single-ply roofing systems pose challenges stemming from their materials. Incorrect installation and inadequate maintenance can adversely impact their construction and longevity. Neglecting these issues may result in blistering and ridges in lap areas, membrane shrinkage, leaks, punctures, wind damage, and detachment.
Multi-Ply Roofing Systems for Low-Slope Roofs
Multi-ply roofing systems represent the most historically significant product category with over 200 years of use. Multi-ply systems offer a prevalent option for low-slope roofs, providing multiple layers of protection from damaging effects, unlike single-ply membranes. Modified bitumen membranes maintain a consistent thickness over their lifespan, whereas single-ply membranes lose thickness due to exposure and weathering. Built-up roof membranes and modified bitumen membranes stand out as a commonly utilized roofing materials for low-slope roofs.
Built-Up Roof (BUR) Membranes
A BUR roofing system, also referred to by some as a “tar and gravel” roof, is constructed through the layering of bitumen and manufactured reinforcement membranes, sometimes surfaced with embedded gravel to form the completed roof assembly. The incorporation of multiple layers offers robust protection to the elements.
BUR membranes prove particularly advantageous for near-zero slope roofs or low-slope roofing systems, boasting several benefits when combined with the use of thermal insulation as part of the roofing assembly:
- Multi-layered protection and water resistance.
- Exceptional thermal performance.
- Resistance to heat conduction between a building’s exterior and interior.
- Fire and uplift resistance.
However, despite their unique design and advantages, BUR systems present challenges. Their installation can be labor intensive. Moreover, BUR membranes can be vulnerable to withstand extreme hot or cold weather conditions. Additionally, the fumes related to the heating of the mopping asphalt utilized during application can pose potential health risks to contractors and installation teams if workers are not properly protected.
Modified Bitumen Roofing (MBUR) Membranes
Polymer Modified Bituminous Membranes consist of premium asphaltic base materials enhanced with rubber or plastic polymers, distinguishing it from traditional asphalt products. Similar to its predecessor, the BUR system, MBUR systems are normally installed in multiple layers, however, some systems are available as a single-layer system. The key distinction in versatility and accelerated performance lies in the modifications made to the base asphalt compound.
The creation of modified bitumen involves incorporating polymers into the asphalt at a molecular level, saturating, and coating fiberglass or polyester reinforcements, to create a resilient roof membrane. This modification renders the membrane impermeable and durable against even severe climatic conditions and the harshest weathering environments.
In comparison to traditional asphalt BUR systems, modified bitumen offers enhanced protection against weatherproofing and greater durability. The membrane exhibits remarkable flexibility, tear resistance, and ease of repair. Moreover, it can withstand a wide range of temperatures without compromising its integrity.
Modified Bitumen Roofing Systems and Products Offered by Polyglass
Polyglass offers an array of Modified Bitumen Roof Assemblies and Products tailored to meet your roofing needs. Whether you require specific materials or complete assemblies, Polyglass USA, Inc. specializes in modified bitumen roofing solutions. Our extensive product line caters to various application methods, ensuring that you find the perfect fit for your roofing project.
Modified Bitumen APP Roofing Membranes
Polyglass manufactures Atactic Polypropylene (APP) modified asphalt roofing membranes, renowned for their durable construction and high-quality plastomeric compounds. These membranes are engineered to deliver long-term weathering performance, ensuring reliability and longevity for your roofing needs.
Our APP membranes are available in both heat-welded and self-adhered options, offered as cap sheets and base/interply sheets, forming integral components of a warranted multi-ply system. Polyglass provides a variety of APP products, including APP Heat-Welded membranes, Self-Adhered APP membranes, as well as base, felt, and synthetic membranes for your roofing needs.
Modified Bitumen SBS Membranes
Polyglass’ Styrene-Butadiene-Styrene (SBS) modified asphalt roofing membranes feature reinforcement with polyester and/or fiberglass mat, ensuring exceptional flexibility, outstanding tensile strength, and dimensional stability. Designed to integrate seamlessly into multi-ply roof systems, Polyglass’ SBS modified bitumen membranes are engineered to meet the demands of various roofing applications.
Polyglass provides a range of SBS products, including Self-Adhering Elastomeric SBS roofing membranes and SBS Heat-Welded membranes.
Self-Adhered Modified Bitumen Membranes
Self-adhered (SA) modified bitumen roofing systems present a safer and efficient alternative to conventional installation methods. When properly installed, self-adhered modified bitumen roofing systems offer the same level of protection as systems applied with hot asphalt or cold adhesive, yet require significantly less time and labor, without the associated safety hazards.
The SA membranes available at Polyglass are engineered to facilitate a cleaner application, expedite installation, and eliminate the need for torches, hot asphalt, or bonding adhesives on-site. This feature is particularly advantageous for sites with restricted access to specialized installation equipment or where the use of torches or hot asphalt is impractical or prohibited.
Polyglass stands at the forefront as the premier manufacturer of self-adhered modified bitumen roofing membranes, incorporating patented ADESO® Technology.
ADESO technology revolutionized the modified bitumen industry by introducing dual-compound self-adhered (SA) membranes. These membranes feature a genuine APP or SBS formulation on the top weathering side and a robust self-adhered formulation on the bottom side of the reinforcement.
ADESO Technology integrates patented elements that enhance lap sealing and facilitate product design with a diverse range of customized surfaces.
Polyglass offers a comprehensive range of self-adhered products for low-sloped roofs, including self-adhered APP and SBS membranes, as well as base sheets, cap sheets, flashing strips, and end laps tailored for various applications and purposes.
Polyglass provides a comprehensive range of products tailored to offer exceptional coverage for virtually any challenge you encounter in your roofing application.
If you have technical inquiries about the best low-slope systems for your project, don’t hesitate to contact our knowledgeable team of experts.