Everything You Need To Know About A Modified Bitumen Roof

Everything You Need To Know About A Modified Bitumen Roof

You’ve probably heard about different types of roofing materials—shingles, metal, tile, you name it. But today, we’re diving deep into the world of Modified Bitumen roofs. If you’ve ever wondered if this type of roofing is for you, read on!

Related Article: 6 Factors That Affect Commercial Roof Lifespan

Your Ultimate Guide to Modified Bitumen Roofing Systems

What Is Modified Bitumen Roof?

Modified Bitumen Roof (Mod Bit for short) is an asphalt-based roofing material designed for low-slope or flat roofs. It emerged as an evolution of asphalt roofing, enhanced with rubber or plastic polymers for superior waterproofing and durability.

The Layers Make the Difference

A Modified Bitumen Roof typically consists of two or more layers. The base layer is a heavy, waterproof material, often reinforced with fiberglass or polyester. On top of this goes a cap sheet with a weather-resistant surface, usually made with granules like those you’d see on asphalt shingles.

Modified Bitumen Roofing Systems

The Benefits


One of the significant advantages of a Modified Bitumen Roof is its durability. Thanks to its multiple layers, this type of roofing can last anywhere from 10 to 20 years with proper maintenance.


Mod Bit roofing systems can flex and adapt, making it less susceptible to cracking in fluctuating temperatures. This is particularly important in climates with extreme temperature variations—like good ol’ Oklahoma!

Water Resistance

The layered structure of this roofing systems provides excellent waterproofing. No more worrying about water ponding or leakages.


While not the cheapest option out there, Mod Bit offers a great balance between cost and performance. Its durability and low maintenance needs make it a wise investment in the long run.

Modified Bitumen Roofing System Installation Methods

You’ve got options here—hot-applied, cold-applied, and torch-applied are the most common. The method used will depend on your specific needs and circumstances, so it’s best to consult with professionals like us to determine the best approach for your property.

Modified Bitumen Roof Systems: Costs

Modified Bitumen Roofing being installed for flat roof

Factors That Influence Cost

Before diving into numbers, it’s important to note that several factors can influence the cost of a Mod Bit roof. The size of your roof, the condition of your existing roofing structure, labor rates in your area, and any additional features you want, like extra insulation or specific finishes, can all impact the final price.

General Cost Estimates

Now, let’s get down to the nitty-gritty. Generally speaking, for a basic Mod Bit roofing system, you can expect to pay anywhere from $4 to $6 per square foot for materials and installation. So, for a 2,000 square foot roof, you’re looking at around $8,000 to $12,000. But remember, this is a general range. More high-end systems with premium features or a complicated installation process can run upwards of $8 per square foot or more.

Life Cycle Cost

While the initial outlay might seem steep, it’s worth considering the long-term value. Modified Bitumen roofs are durable, often lasting 10 to 20 years with proper maintenance. So, over its lifetime, the cost becomes much more manageable, especially when you factor in reduced repair and maintenance expenses.

Professional Consultation

The best way to get an accurate cost estimate tailored to your needs is through a professional consultation. We’ll take into account all the variables—your specific roof’s condition, its size, your material preferences, and more—to provide you with a detailed and accurate quote.

Maintenance Tips

The Modified Bitumen Roofing System is pretty low-maintenance, but like any roofing material, they do benefit from regular inspections and upkeep.

Keep Modified Bitumen Roofing System Clean: More Than Just Aesthetics

First things first: a clean roof is a happy roof. We’re not just talking about curb appeal here; we’re talking about extending the life of your roof. Leaves, twigs, and other debris can accumulate on your roof, especially after storms. This debris can trap moisture, leading to possible water damage or even mold and mildew growth. So, it’s essential to regularly clean off any accumulated debris. Depending on the surrounding environment, like if you have overhanging trees, you might want to do this seasonally or even more often.

modified bitumen membranes being installed on flat roof

Water Ponding: No, You Don’t Want a Rooftop Pool

Watch out for water ponding, especially after heavy rains. Modified Bitumen Roofing System is good at handling water, but no material loves sitting water for an extended period. Pooling water can cause sagging and, over time, serious structural issues. If you notice water ponding, it’s a sign you should consult a professional for an assessment and possible drainage solutions.

Seal and Patch: The Dynamic Duo

Check for any lifted seams or minor punctures in the roof’s surface. These may seem small but could lead to leaks and greater damage over time. With Modified Bitumen Roofing System, these can often be sealed or patched pretty easily but should be addressed promptly. Depending on your roof’s condition, a bitumen-compatible sealant can work wonders. Just make sure to consult an experienced commercial roofing contractor like Robbins Roofing to get the right materials and application.

Annual Professional Inspections: The Ounce of Prevention

While regular visual checks are beneficial, nothing replaces the keen eye of a professional inspection. We recommend an annual roofing systems inspection to identify any potential issues that might go unnoticed by the untrained eye. This is where we can look for signs of wear and tear, examine seams, and assess the overall integrity of your roof. Think of it as a check-up for your home; catching minor issues early can prevent costly repairs down the line.

So, there you have it! Modified Bitumen roofing offers a strong, flexible, and water-resistant solution that’s particularly suited for low-sloped or flat roofs. If you’re considering a Mod Bit roof or a simple metal roof replacement, you’re in good hands with Robbins Roofing. We can guide you through the selection, installation, and maintenance process, ensuring you get the most out of your investment.

Got questions or ready to take the plunge? Give us a call, and let’s talk roofs!