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Asphalt-Based Roofing Systems: BUR & Modified Bitumen

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Proven Protection for Commercial & Industrial Roofs

Highland Roofing offers reliable asphalt-based roofing systems designed to withstand the demands of commercial buildings across Louisville and Southern Indiana. From traditional Built-Up Roofing (BUR) to modern Modified Bitumen (Mod Bit) membranes, these multi-ply systems provide exceptional waterproofing, flexibility and long-term durability.

Whether you’re facing an aging flat roof or planning a new installation, our expert team delivers time-tested roofing solutions backed by over 135 years of local experience.

What Are Asphalt Roofing Systems?

Asphalt-based roofing systems are built with layers of asphalt and reinforcing plies, forming a flexible yet robust barrier against moisture and weather. These systems are ideally suited for low-slope and flat commercial roofs, providing:

  • Multiple waterproofing layers for built-in redundancy
  • Strong resistance to UV rays, hail, and heavy rainfall
  • A more proven alternative to single-ply or metal systems

Both BUR and Modified Bitumen systems offer unique advantages, but all rely on asphalt as the core waterproofing material.

Quick Benefits

Exceptional waterproofing performance, UV & storm resistance, and proven long-term value for Louisville businesses.

Built-Up Roofing (BUR)

Commonly known as “tar and gravel” roofs, BUR systems have been used for over a century. They consist of alternating layers of hot asphalt and reinforcing felts (often fiberglass or organic), topped with a gravel or mineral-surfaced finish.

Benefits of BUR:

  • Long-term durability from multiple waterproofing layers
  • Excellent fire and UV resistance
  • Outstanding protection against foot traffic and impact
  • Ideal for large commercial buildings with flat or low-pitch roofs

Built-Up systems are favored in warehouses, schools, and healthcare facilities where redundancy and lifespan are essential.

Modified Bitumen Roofing (Mod Bit)

Modified Bitumen roofs evolved from BUR technology, combining asphalt with modern polymer modifiers to improve flexibility, especially in extreme temperatures – something Louisville sees in both summer and winter.

Types of Modified Bitumen:

  • SBS (Styrene-Butadiene-Styrene): Flexible and resilient; best for freeze-thaw cycles
  • APP (Atactic Polypropylene): UV-resistant and durable in high heat

Installation methods include torch-down, cold adhesive or self-adhered sheets – allowing customized solutions for your building.

Why Choose Mod Bit?

  • Greater flexibility than BUR
  • High tensile strength
  • Fast, low-odor installation methods
  • Excellent choice as an alternative to a built up roof system 

Advantages of Asphalt-Based Roofs

Asphalt systems remain a go-to option for commercial roofing because they consistently perform under pressure:

  • Exceptional waterproofing
  • UV and storm resistance
  • Long-lasting with proper maintenance
  • Easy to repair and maintain
  • Cost-effective for long-term performance
  • Proven track record in Louisville’s commercial climate

Installation & Maintenance

Highland Roofing brings precision and care to every installation. Our crews are highly trained in asphalt roof systems and adhere to the industry’s highest safety and quality standards.

Extend Your Roof’s Lifespan

We also offer a Preventative Maintenance Program tailored to flat and low-slope systems. This service helps identify issues early, prevent costly damage, and ensure your roof performs year-round.

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Why Louisville Businesses Choose Highland Roofing

Highland Roofing has served Kentucky’s businesses since 1890, delivering trusted roofing solutions for generations. From factories to retail centers, our clients know they can count on us for:

  • Over 135 years of commercial roofing experience
  • Local knowledge of Louisville weather and building codes
  • Family-owned service across five generations
  • Licensed, insured, and safety-first crews
  • Work backed by warranties and ongoing support

We’re more than roofers. We’re your long-term roofing partners.

Ready for a Roof That Lasts?

Whether you need a new Mod Bit roof, a BUR system for a flat warehouse, or just a trusted opinion — we’re here to help.

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Asphalt Roofing Systems: Frequently Asked Questions

BUR is the traditional “tar and gravel” system — alternating layers of hot asphalt and reinforcing felts topped with gravel or a mineral surface. Modified bitumen evolved from BUR by blending polymer modifiers into the asphalt, producing a more flexible membrane that installs in fewer plies. BUR gives you maximum redundancy and impact resistance; mod bit gives you better movement through Louisville’s freeze-thaw swings and a faster install.

With proper installation and regular maintenance, BUR systems commonly last 20 to 30 years and modified bitumen systems 20 to 25 years. Drainage, foot traffic, and how quickly small flashing and seam failures get caught matter as much as the membrane itself — which is why we pair every asphalt system with a preventative maintenance plan.

SBS (styrene-butadiene-styrene) stays flexible in cold weather and handles freeze-thaw cycling well, which makes it the usual choice for Louisville winters. APP (atactic polypropylene) is more UV-resistant and holds up better under sustained high heat. We spec the membrane based on your building’s slope, sun exposure, and how the roof will be used.

They solve different problems. Asphalt-based systems give you multiple waterproofing layers for built-in redundancy and stand up better to foot traffic and impact. Single-ply membranes are lighter and often less expensive up front. For warehouses, schools, and healthcare facilities where a leak is expensive, the redundancy of a multi-ply asphalt system usually wins.

Usually, yes. Asphalt-based systems are among the easiest commercial roofs to repair because the material is patchable and readily available. A roof survey tells us whether you are dealing with isolated flashing or seam failures, which are repairable, or saturated insulation across the deck, which calls for replacement.

Three methods: torch-applied, cold adhesive, and self-adhered sheets. Torch-down produces the strongest seams, while cold adhesive and self-adhered sheets are low-odor and low-flame — an important consideration on occupied buildings like schools and medical offices. We recommend the method based on your building’s occupancy and fire requirements.

Experts since 1890

Throughout multiple generations, our impressive legacy of leadership has consistently left a lasting impression on our local clientele. For five successive family generations, our unwavering commitment to excellence and prioritizing the needs of our customers has remained our guiding principle.

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