I Have a Flat Roof. What's Available?

Published on: 8/1/2023

5 mins read

Three of the most commonly used types of flat roofing materials are Built-Up Roofing (BUR), Modified Bitumen Roofing, and Single-Ply Membrane Roofing. Each type has its unique characteristics, advantages, and drawbacks, making them suitable for different applications and environments.

Built-Up Roofing (BUR):

Built-Up Roofing, often referred to as "tar and gravel" roofing, is one of the oldest and most traditional flat roofing materials. BUR consists of multiple layers of bitumen, typically asphalt, and reinforcing materials such as fiberglass or organic felts. The layers are alternated and applied with hot asphalt or cold-applied adhesive, creating a durable and robust roofing system.

One of the key benefits of BUR is its exceptional waterproofing capability due to the multiple layers of bitumen and felts, making it highly resistant to leaks. Moreover, the aggregate surfacing, often gravel or mineral granules, provides excellent UV protection, increasing the roof's lifespan. BUR can endure heavy foot traffic and is relatively low in maintenance, making it suitable for commercial and industrial buildings.

However, BUR has some drawbacks. It can be labor-intensive to install, making it more expensive initially. Additionally, the hot asphalt application can release strong odors and require skilled labor. Furthermore, BUR tends to be heavy, so it may require additional structural support.

Modified Bitumen Roofing:

Modified Bitumen Roofing is an evolution of BUR, incorporating polymer-modified bitumen sheets instead of the multiple layers of hot-applied bitumen. The polymer reinforcement enhances the material's flexibility, weather resistance, and elongation properties, making it ideal for areas with temperature fluctuations.

Modified Bitumen Roofing can be installed using various methods, including torch-applied, cold-applied, or self-adhered sheets. Torch-applied sheets are heated to bond to the substrate, while cold-applied sheets use adhesives. Self-adhered sheets have a peel-off backing that sticks to the roof.

This roofing material offers excellent durability, resistance to punctures, and ease of repair. It is well-suited for both commercial and residential applications and works effectively in areas with extreme weather conditions.

One drawback of Modified Bitumen Roofing is that torch-applied installation can pose a fire risk, making it unsuitable for certain buildings or locations. However, cold-applied and self-adhered methods eliminate this concern.

Single-Ply Membrane Roofing:

Single-Ply Membrane Roofing is a popular flat roofing material known for its ease of installation and versatility. It comes in large rolls of flexible synthetic materials, primarily EPDM (Ethylene Propylene Diene Monomer), PVC (Polyvinyl Chloride), and TPO (Thermoplastic Olefin).

EPDM is a rubber-like material that offers excellent weather resistance, UV protection, and durability. PVC and TPO are thermoplastic materials with added reinforcement that provides strength and chemical resistance. Single-ply membrane Roofing is usually mechanically attached, adhered, or ballasted to the roof.

One significant advantage of Single-Ply Membrane Roofing is its lightweight nature, which minimizes the need for additional structural support. The installation process is quicker and less labor-intensive compared to BUR or Modified Bitumen. Additionally, Single-Ply Membrane Roofing is highly resistant to environmental factors, including chemicals, oils, and microbial growth.

However, Single-Ply Membrane Roofing can be vulnerable to punctures and tears, especially during installation or due to heavy foot traffic. Proper installation and maintenance are critical to ensuring its long-term performance.

In conclusion, Built-Up Roofing, Modified Bitumen Roofing, and Single-Ply Membrane Roofing are three commonly used flat roofing materials, each offering unique advantages and disadvantages. The choice of material should be based on factors such as budget, building type, climate, and specific project requirements. Proper installation and regular maintenance are key to maximizing the longevity and performance of any flat roofing system.