When deciding on the best flat roofing system for your commercial property, the debate of roll roofing vs modified bitumen often arises. Both are popular choices for flat and low-slope roofing projects, but they differ significantly in terms of materials, installation methods, durability, and ideal use cases.
For commercial property owners and building managers, making the right choice requires understanding:
- The composition and performance capabilities of roll roofing and modified bitumen
- Installation and maintenance requirements for each system
- How each roofing solution suits specific projects and budget constraints
This comprehensive comparison will help you determine the better roofing option for your commercial property.
What Is Roll Roofing?
Roll roofing is one of the simplest and most cost-effective flat roofing solutions available. It’s made of asphalt-saturated material, similar to shingles but in long rolls, making it an appealing option for those seeking a straightforward and inexpensive roofing system.
✅ Advantages of Roll Roofing
- Cost-Effective: Roll roofing is a budget-friendly choice, both in terms of materials and installation. It’s an ideal solution when affordability is a top priority.
- Ease of Installation: Roll roofing can often be installed without specialized tools or expertise, which significantly shortens project timelines and reduces labor costs.
- Lightweight Material: Its lightweight composition makes it easy to transport and work with, especially for small or simple roofing projects.
❌ Drawbacks of Roll Roofing
While roll roofing is affordable and simple, it does have limitations:
- Shorter Lifespan: Compared to other flat roofing materials, roll roofing typically lasts only 5–10 years, depending on the application and climate.
- Limited Durability: Roll roofing may not hold up as well in areas with high foot traffic or extreme weather conditions, such as heavy storms or snow loads.
- Less Aesthetic Appeal: Its plain appearance and visible seams make it less desirable for properties where aesthetics are important.
Roll roofing may work for sheds, garages, or low-budget commercial projects, but its drawbacks make it less ideal for larger or high-value buildings.
What Is Modified Bitumen Roofing?
Modified bitumen is a more advanced flat roofing solution designed for durability and extended lifespan. This material is an evolution of the traditional built-up roofing systems but incorporates innovative components to improve performance.
How Modified Bitumen Works
Modified bitumen roofing is composed of layers of asphalt mixed with rubber or plastic polymers, which provide extra flexibility and strength. These layers are typically reinforced with fiberglass or polyester for added durability. Modified bitumen roofing systems are applied in rolls, but they require specialized installation methods, such as torch-down, cold adhesive, or peel-and-stick.
✅ Benefits of Modified Bitumen
- Durability: Modified bitumen is highly resistant to tears, punctures, and impacts, making it ideal for commercial roofs that encounter heavy use or weather-related strain.
- Extended Lifespan: With proper maintenance, modified bitumen roofing can last 20+ years, far outperforming roll roofing.
- Versatility: Modified bitumen is well-suited for a variety of flat roofing projects, with options for single-layer or multi-layer installations.
- Weather Resistance: Its improved material composition makes it resistant to UV rays, temperature fluctuations, and moisture infiltration.
❌ Potential Disadvantages of Modified Bitumen
- Higher Costs: Due to its enhanced performance, modified bitumen materials and installation expenses are typically higher than roll roofing.
- Complex Installation Process: Installing modified bitumen requires professional skills and equipment, which increases labor costs and project timelines.
Despite these drawbacks, modified bitumen is a preferred choice for commercial flat roofing projects where long-term durability and protection are a priority.
Installation Processes Compared
One of the key differentiators between roll roofing and modified bitumen lies in how they are installed. Each has specific methods that influence cost, time, and expertise.
Roll Roofing Installation
Roll roofing is one of the fastest installations among flat roofing systems. Here’s how it’s typically done:
- Prepare the Roof Surface: The roof must be cleaned and primed to ensure the roll roofing adheres properly.
- Cut and Position the Rolls: Long sheets of roll roofing are cut to size and placed on the roof deck.
- Nailing or Adhesive Application: The roofing sheets are nailed down or adhered with a roofing cement or similar adhesive, depending on the method chosen.
Because roll roofing requires minimal equipment and expertise, it’s often done by property owners themselves or general contractors without roofing specialization. However, this simplicity comes with its drawbacks in terms of durability and lifespan.
Modified Bitumen Installation
The installation of modified bitumen involves more advanced techniques and greater precision. Common methods include:
- Torch-Down: Heat is applied to a torch-down membrane for strong adhesion to the roof surface.
- Cold Adhesive or Peel-and-Stick: A safer alternative to torching, this employs adhesives or self-adhering sheets to secure the material.
These methods require trained roofing professionals to ensure proper application, but the long-term performance often justifies the upfront effort and cost.
Roll Roofing vs. Modified Bitumen by the Numbers
Roll roofing and modified bitumen are two great options for low-slope roofs, but each comes with its own pros and cons. Here’s a quick breakdown to help you decide:
Roll Roofing
- Budget-Friendly: Great for smaller budgets and quick fixes.
- Lightweight & Easy to Install: Perfect for DIYers or temporary projects.
- Shorter Lifespan: Not as durable as other roofing materials.
- Best For: Small projects, sheds, or temporary solutions.
Modified Bitumen
- Durable & Long-Lasting: Designed to handle tough weather and resist leaks.
- Reinforced for Strength: Made with asphalt and polymers for flexibility and durability.
- Weather Resistant: Holds up against rain, wind, and heat.
- Higher Upfront Cost: Requires more investment and professional installation.
- Best For: Long-term roofing projects where reliability is key.
Key Takeaway:
Choose roll roofing if you need a quick, low-cost option for a smaller project. Opt for modified bitumen when durability, weather resistance, and longevity are your top priorities.
When to Choose Roll Roofing vs. Modified Bitumen
Roll Roofing Works Best For:
- Temporary roofing solutions
- Small outbuildings such as sheds or garages
- Low-budget or DIY roof replacements
- Projects in mild climates with minimal exposure to severe weather
Modified Bitumen is Ideal For:
- Large-scale commercial properties
- High-use flat roofing systems that encounter foot traffic
- Urban environments requiring greater weatherproofing
- Long-term roofing investments with maximum durability
How to Choose the Right Roofing System for Your Project
If you’re still unsure whether you need roll roofing or modified bitumen, follow this 3-step analysis to make a decision:
🔍 Assess Your Building’s Needs
- Is your roof exposed to harsh weather conditions or heavy foot traffic?
- Are you seeking a long-term solution or a temporary fix?
💵 Evaluate Your Budget
- Factor in both short-term upfront costs and long-term maintenance expenses.
- Consider how the roof’s lifespan will influence your financial plan.
👷 Consult with Professionals
- A roofing expert can evaluate your flat roofing requirements and provide professional recommendations for your specific project.
Every building is unique. While roll roofing may suffice for utility-focused structures, commercial properties with high-value assets often require the durability of modified bitumen.
Conclusion
When deciding between roll roofing vs modified bitumen, it’s crucial to weigh the pros and cons of each system in the context of your specific project needs and objectives. Roll roofing may fit smaller, low-cost projects, whereas modified bitumen is the gold standard for durable and weather-resistant commercial flat roofing systems.
At G. Cannon, we take the guesswork out of choosing the best flat roofing material for your property. With extensive experience, skilled professionals, and a commitment to quality craftsmanship, our team is the team you trust to provide superior roofing solutions for every need.
Contact us today! Your roofing success is just one decision away.
