Modified bitumen roofing isn’t some fancy trend. It’s the workhorse flat roofing system property owners in Maryland turn to when they want proven roofing reliability without surprises.
At RoofPRO, we install, replace, and service modified bitumen roofing systems throughout Maryland. Our team brings technical skill, practical know-how, warranties, and the kind of local experience you need when you want things done right the first time.
What Is Modified Bitumen Roofing?
Modified bitumen (mod bit) is a layered, asphalt-based roofing system designed for low-slope or flat roofing surfaces. Modified bitumen roofing is a tough, layered roofing material. It’s similar in composition to traditional built-up roofing (BUR), but incorporates modern polymers that enhance its performance and resilience.
The core of every modified bitumen roof is asphalt that’s been “modified” with polymers (usually either Atactic Polypropylene (APP) or Styrene-Butadiene-Styrene (SBS)). This material is reinforced with fiberglass or polyester sheets, then finished with a protective cap sheet (sometimes granulated, sometimes smooth).
Brands like GAF, CertainTeed, and Polyglass manufacture some of the best modified bitumen membranes you’ll find on Maryland rooftops.
How does modified bitumen compare to other flat roof systems?
Unlike single-ply options (like TPO or EPDM), modified bitumen uses multiple plies for added thickness and redundancy. This gives you better puncture resistance and an extra layer of security against leaks. These membranes can be installed using several methods:
- Torch-down: Fuses the membrane using an open flame.
- Cold adhesive: Applies without heat, safer in sensitive environments.
- Self-adhered: Pre-treated with adhesive for clean, efficient application.
Our Modified Bitumen Roofing Services
We install and service mod-bit roofing systems across Maryland. Whether you need a full replacement, a new installation, or a surface upgrade, we are here to service your roof throughout its lifecycle while protecting your building and your budget.
- New Installation – Ground-up builds and retrofits on commercial, multifamily, and residential additions.
- Complete Tear-Off and Replacement – Remove other roofing systems or waterlogged layers, add fresh insulation, and install a new multi-ply assembly within code.
- Targeted Roof Repairs – Seal split seams, replace blistered sections, and correct membrane shrinkage to repair leaks.
- Preventive Maintenance Plans – Semi-annual inspections, core sampling, infrared scans, and detailed reporting that keeps warranties valid.
- 24-Hour Emergency Leak Response – Reach a live RoofPRO dispatcher any time and get crews on-site, often the same evening.
Benefits of Modified Bitumen Roofing for Maryland
We see a lot of roof systems in our work, but modified bitumen continues to stand out for several reasons, especially in our climate.
- Handles Maryland’s Weather: From blazing hot summers to icy winters, modified bitumen can take the temperature swings and stay strong year after year.
- Durability and Longevity: Properly installed and maintained, these roofs routinely last 20+ years. The reinforcement resists tears, punctures, and the kind of shrinking or cracking that shortens other roofs’ lifespans.
- Energy Efficient Options: With reflective “cool roof” coatings available, you can reduce heat absorption and help keep your building’s energy costs in check.
- Wind Resistance: Modified bitumen’s composition naturally holds up well during storms with strong winds.
- Low Maintenance Needs: Fewer seams than traditional built-up roofs means fewer weak spots. And if you do need repairs, patching is straightforward.
- Cost-Effective Protection: You get reliable performance at a competitive price, which is a big reason so many commercial property owners in Maryland prefer it.
- Layered defense. Multi-ply installation offers built-in redundancy that enhances leak resistance.
- Flexible membrane. SBS-modified membranes handle movement better than many single-ply options.
Types of Modified Bitumen Roofing Systems
No two buildings are exactly alike. We’ll help you select the system that best matches your property, your budget, and the unique needs of your building. That’s why modified bitumen comes in different types and installation methods.
- APP vs. SBS:
- APP (Atactic Polypropylene): APP-modified bitumen membranes are commonly installed with heat (torch-down method). They’re tough, UV-resistant, and less likely to degrade under intense sunlight.
- SBS (Styrene-Butadiene-Styrene): SBS-modified bitumen is more flexible, especially in cold weather. It can be installed with hot asphalt, cold adhesives, or as a self-adhered membrane.
- Installation Methods:
- Torch-Applied: Uses a torch to bond the membrane to the roof deck. This is a popular choice for commercial jobs but requires experienced installers for safety.
- Self-Adhered: Rolls out and sticks to the surface—no torch needed. Cleaner, faster, and safer for occupied buildings.
- Cold-Applied: Uses adhesive for attachment, making it a good fit when you want to avoid heat or open flames.
- Surface Options:
- Granulated: Has a textured, shingle-like finish that adds protection from the sun and foot traffic.
- Smooth/Reflective Coatings: Great for maximizing reflectivity and lowering building temperatures.
Modified Bitumen Roofing Installation Process
Getting a modified bitumen roof from RoofPRO is a straightforward process, but each step matters.
- Inspection & Prep: We start by evaluating your current roof. If the deck is solid, we clean and prep the surface. If there’s hidden damage, we fix it before going any further.
- Layering: First goes the base sheet, then a second base sheet of modified bitumen membrane depending on your roof package, topped with a cap sheet.
- Application: Depending on the system chosen (torch, self-adhered, or cold-applied), our team applies each layer with care—making sure seams are tight and everything is properly sealed.
- Quality Checks: We double-check seams, flashings, and penetrations for leaks or weaknesses.
- Cleanup and Walkthrough: Once we’re finished, we clean up every scrap and walk you through the new system so you know exactly what’s overhead.
Modified Bitumen Roofing vs. Other Flat Roofing Options
Property owners often ask us how modified bitumen compares to other flat roofing types.
Modified bitumen comes in both entry-level and higher-end systems. The basic setup uses one base sheet and one cap sheet and normally lasts about 12 years. The upgraded system uses two base sheets and one cap sheet and can reach roughly 20 years.
By comparison, TPO, PVC, and EPDM generally start as 20-year systems and can extend to 30 years with thicker mil options. These membranes are single-ply, have far fewer seams, and TPO and PVC feature heat-welded seams for added durability.
Because of these differences, modified bitumen tends to be a strong fit for residential homes, while TPO, PVC, and EPDM are more commonly used on commercial buildings.
Modified bitumen is a middle-ground system: more rugged than single-ply but easier to maintain than old-school built-up roofing. We help our customers pick what works for them, factoring in the building’s use, expected traffic, and the owner’s long-term goals.
Why Maryland Chooses RoofPRO
When you want modified bitumen roofing that’s built to last, trust a team with local expertise and real, proven results. We take the time to do the job right, use the best products, and back our work with real support.
We’ve spent over 20 years building relationships with Maryland property owners, and our work speaks for itself. We know the local codes, the permitting process, and how Maryland weather affects roofing systems.
- Certified & Insured – We maintain current OSHA safety training, full liability coverage, and certifications from leading manufacturers. We do the work right, so your warranty stays intact.
- Transparent Process – You’ll always know what’s happening, when it’s happening, and why. We take the time to answer questions, explain materials, and give real guidance.
- Warranties & Quality Control – Many of the modified bitumen systems come with 10, 15, or 20-year warranties, depending on the material and install method. We also back our labor with a workmanship guarantee.
Who We Serve
Modified bitumen roofing works for a wide range of building types, and so do we. If you manage a flat-roofed property anywhere in Maryland, we’ve likely worked on a building like yours. Our clients include:
Commercial & Industrial
- Warehouses and logistics centers
- Retail centers and strip malls
- Office buildings and business parks
Multi-Family & Residential Complexes
- Condominium associations
- Apartment buildings
- Senior living and assisted care facilities
- Garage roofs
Public & Institutional
- Government buildings
- Medical offices and clinics
- Religious facilities and churches
- Schools and university buildings
Get a Free Quote for Modified Bitumen Roofing in Maryland
Thinking about a modified bitumen roof for your property? We make it simple to get started. Contact us for a no-pressure inspection and estimate. We’ll review your building’s needs, explain your options, and give you a clear breakdown of costs.
We offer free on-site consultations across Maryland. After your inspection, we’ll provide a full proposal with system recommendations, pricing, and a clear timeline. Give us a call or fill out the form below, and we’ll help you figure out if modified bitumen is the right choice for your roof.
Author Bio
Tim Taylor – Owner & Founder of RoofPRO
Tim Taylor began his roofing career in 2003 and founded RoofPRO in 2004 with a mission to fix the poor workmanship that often causes roof leaks. With over 20 years of hands-on experience, he’s earned elite credentials like CertainTeed’s ShingleMaster Wizard certification, HAAG inspection certifications, and OSHA safety training. His expertise in leak repair, flashing repair, and post-storm restoration has made RoofPRO one of Maryland’s most trusted roofing companies. Tim continues to lead with the same principle that built his reputation—roof it right the first time.