Commercial Asphalt Roof

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Commercial Asphalt Roof -When it comes to protecting large commercial buildings, roofing is one of the most critical investments a business can make. The right roofing system safeguards valuable assets, ensures energy efficiency, and adds longevity to the property. Among the many options available, commercial asphalt roofing has remained a trusted solution for decades thanks to its durability, cost-effectiveness, and versatility.

In this guide, we’ll explore the fundamentals of asphalt roofing for commercial applications, the different types available, advantages and drawbacks, installation processes, maintenance requirements, and cost considerations.

What Is Commercial Asphalt Roofing?

Commercial asphalt roofing refers to roofing systems made primarily with asphalt-based materials. Asphalt is a sticky, waterproof, petroleum-derived material that has been used for roofing for over 100 years. In commercial settings, it is often applied in flat or low-slope roofing systems, making it a popular choice for warehouses, office buildings, schools, and industrial facilities.

Unlike residential asphalt shingles (commonly used for pitched roofs), commercial asphalt roofing involves advanced techniques and systems, including built-up roofing (BUR), modified bitumen roofing, and sometimes asphalt shingles on steep-slope commercial roofs.

Types of Commercial Asphalt Roofing Systems

Built-Up Roofing (BUR)

  • Overview: BUR is one of the oldest and most reliable asphalt roofing systems, also known as “tar and gravel roofs.” It consists of multiple layers (or plies) of asphalt alternated with reinforcing fabrics.

  • Surface Options: Gravel, reflective coatings, or mineral cap sheets.

  • Strengths: Excellent waterproofing, proven track record, durable under heavy foot traffic.

Modified Bitumen Roofing

  • Overview: An evolution of BUR, modified bitumen systems combine asphalt with modifiers like APP (atactic polypropylene) or SBS (styrene-butadiene-styrene) to enhance flexibility and strength.

  • Installation: Can be torch-applied, cold-applied with adhesives, or self-adhered.

  • Strengths: More flexible in cold weather, excellent resistance to cracking, easier repairs compared to BUR.

Asphalt Shingles for Commercial Steep-Slope Roofs

  • Overview: While not common for flat roofs, asphalt shingles are sometimes used on hotels, retail centers, and multifamily buildings with steep slopes.

  • Strengths: Affordable, wide range of styles, effective for smaller commercial properties.

Advantages of Commercial Asphalt Roofing

Proven Durability

Asphalt has been used for over a century in commercial applications, offering strong resistance to water, UV rays, and wind damage. With proper installation and maintenance, BUR and modified bitumen systems can last 20–30 years.

Cost-Effectiveness

Compared to single-ply membranes like TPO or PVC, asphalt systems are often more affordable upfront. Asphalt shingles also remain one of the most economical steep-slope roofing materials.

Excellent Waterproofing

The multi-ply design of BUR and the rubber-like qualities of modified bitumen provide superior waterproofing, reducing the risk of leaks in flat or low-slope applications.

Flexibility and Versatility

Modified bitumen roofing adapts well to temperature changes, making it ideal for climates with hot summers and freezing winters.

Low Maintenance and Easy Repairs

Routine inspections and minor patching can extend the life of asphalt roofs significantly. Modified bitumen systems, in particular, allow for relatively simple repairs.

Disadvantages to Consider

While asphalt roofing has many strengths, it’s not without drawbacks:

  1. Weight: BUR systems are heavy due to multiple asphalt layers and gravel surfacing. This requires strong structural support.

  2. Installation Complexity: Torch-applied modified bitumen and hot asphalt BUR installations require specialized labor and safety precautions.

  3. Heat Absorption: Asphalt tends to absorb heat, which can increase cooling costs unless reflective coatings or surfacing are applied.

  4. Shorter Lifespan vs. Modern Membranes: Single-ply options like TPO and PVC may last longer (up to 30+ years) with less maintenance.

The Installation Process

The installation process depends on the chosen asphalt roofing system:

Built-Up Roofing (BUR)

  1. Surface Preparation: Roof deck cleaning and priming.

  2. Base Sheet Application: First asphalt layer installed with reinforcing fabric.

  3. Additional Layers: Successive plies of asphalt and felt or fabric applied.

  4. Surfacing: Gravel or mineral cap sheet added for UV protection.

Modified Bitumen

  1. Base Layer: A base sheet is attached to the deck.

  2. Asphalt Membrane Application: Modified bitumen rolled out and adhered using torch, hot asphalt, or cold adhesives.

  3. Cap Sheet: A protective top layer is added for UV and weather resistance.

Asphalt Shingles

  1. Underlayment Installation: Roofing felt or synthetic material installed.

  2. Shingle Application: Shingles nailed in overlapping rows.

  3. Flashing and Sealing: Roof penetrations sealed for waterproofing.

Maintenance Requirements

Asphalt roofing requires routine inspections and preventive care to maximize longevity:

  • Semi-Annual Inspections: Check for blisters, cracks, loose seams, and ponding water.

  • Cleaning: Remove debris, leaves, and dirt to avoid drainage issues.

  • Coating Applications: Reflective coatings can extend roof life and improve energy efficiency.

  • Repairs: Promptly patch any small punctures or damaged sections.

Cost of Commercial Asphalt Roofing

The cost of commercial asphalt roofing depends on the system chosen, roof size, and complexity:

  • Built-Up Roofing (BUR): $4 to $10 per square foot

  • Modified Bitumen: $3.50 to $8 per square foot

  • Asphalt Shingles (steep-slope): $3 to $5.50 per square foot

Factors that influence cost include:

  • Roof accessibility

  • Number of plies (for BUR)

  • Method of application (torch, cold-applied, etc.)

  • Regional labor rates

  • Additional features (insulation, coatings, drainage improvements)

Energy Efficiency and Sustainability

While asphalt roofing is not as reflective as some modern membranes, energy efficiency can be improved by:

  • Installing cool roof coatings to reduce heat absorption

  • Using light-colored surfacing materials

  • Adding insulation layers under the roof system

In terms of sustainability, asphalt roofing materials can often be recycled into new paving materials, reducing landfill waste.

Choosing the Right Contractor

Since installation quality directly affects performance, selecting the right contractor is critical. Look for:

  • Licensed and insured roofing contractors

  • Experience with commercial asphalt systems

  • References from previous projects

  • Manufacturer certifications for modified bitumen products

  • Warranties covering both materials and workmanship

Is Commercial Asphalt Roofing Right for You?

Commercial asphalt roofing remains a reliable, affordable, and proven solution for flat and low-slope buildings. It is especially suitable for property owners who want:

  • A cost-effective roofing system

  • Proven durability and weather resistance

  • A flexible system that adapts to various climates

  • Straightforward maintenance and repair processes

However, businesses looking for lighter-weight systems with greater energy efficiency may consider alternatives like TPO, EPDM, or PVC membranes.

Conclusion

Commercial asphalt roofing has stood the test of time as one of the most durable and cost-effective solutions for protecting large buildings. Whether choosing traditional built-up roofing, modern modified bitumen, or steep-slope asphalt shingles, property owners can rely on asphalt systems to provide strong waterproofing and dependable performance.

By understanding the different types, benefits, and considerations, and by working with qualified roofing contractors, businesses can make informed decisions that protect their investment and ensure long-lasting roof performance.