Popular Types of Commercial Roofing Systems in California Explained

The types of commercial roofing systems available today vary widely in materials, installation methods, performance characteristics, and cost. Whether you are planning a commercial roof replacement, evaluating your current system, or budgeting for a new construction project, understanding the most common options helps you make a well-informed decision for your building and budget.

The Most Common Types of Commercial Roofing Systems

Commercial buildings across San Jose and the greater South Bay are predominantly flat or low-slope, and that slope determines which roofing systems are most practical and code-compliant. The overview below covers the systems most frequently specified for commercial properties in the region.

TPO (Thermoplastic Polyolefin)

Expected lifespan: 20 to 30 years with proper maintenance.

TPO has become one of the most widely installed commercial roofing membranes in the country over the past two decades, and it is easy to see why. It is a single-ply thermoplastic membrane that is heat-welded at the seams to create strong, continuous bonds. According to the NRCA, the welded seams are generally considered more durable than adhesive-bonded alternatives and less vulnerable to separation over time.

TPO is typically white or light-colored, which gives it strong solar reflectance properties. This makes it a natural fit for California’s Title 24 energy code requirements for low-slope commercial roofs, which state minimum standards for how much heat and sunlight a roof reflects. For building owners focused on reducing cooling loads in warmer months, TPO is frequently a top consideration.

PVC (Polyvinyl Chloride)

Expected lifespan: 20 to 30 years, with some installations performing well beyond that range.

PVC roofing membranes share several characteristics with TPO, including heat-welded seam construction and reflective properties, but they have a longer track record in commercial roofing and offer some distinct performance advantages. PVC is particularly resistant to chemicals, grease, and animal fats, which makes it a preferred system for restaurants, food processing facilities, and industrial buildings where rooftop exhaust or chemical exposure is a factor.

PVC membranes are also highly resistant to ponding water, which is an important consideration for flat roofs with drainage challenges. Like TPO, PVC supports cool roof compliance under California’s energy code.

EPDM (Ethylene Propylene Diene Monomer)

Expected lifespan: 20 to 25+ years depending on installation quality and maintenance frequency.

EPDM is a thermoset rubber membrane that has been a mainstay in commercial roofing for more than 50 years. Unlike thermoplastic systems, EPDM cannot be re-fused with heat after curing, so seams are bonded using adhesive tape or liquid adhesive. It is available in black and white and is known for its flexibility in a wide range of temperatures.

EPDM is a durable, cost-effective option for building owners looking for a proven system with a long service history. It handles UV exposure well and resists ozone degradation over time. While its black version absorbs more heat than reflective membranes, white EPDM is available for applications where cool roof compliance is required.

Modified Bitumen

Expected lifespan: 15 to 20 years depending on the number of layers and maintenance.

Modified bitumen roofing is an asphalt-based system that evolved from traditional built-up roofing (BUR). It is composed of asphalt reinforced with rubber or plastic modifiers and installed in multiple layers, which gives it added strength and redundancy compared to single-ply systems.

There are two main types of modified bitumen:

• APP (Atactic Polypropylene): Typically torch-applied, good UV resistance, and less flexible than SBS.
• SBS (Styrene-Butadiene-Styrene): More flexible and rubber-like, often cold-applied or self-adhered, and well-suited to roofs with varying temperatures.

Modified bitumen is a solid choice for roofs that see significant foot traffic or require a more robust surface layer. It works well on buildings with rooftop mechanical equipment that requires regular access.

Built-Up Roofing (BUR)

Expected lifespan: 15 to 30 years depending on the number of plies and surface type.

Built-up roofing is one of the oldest commercial roofing methods still in active use. It is constructed by alternating layers of bitumen and reinforcing felts, typically topped with a gravel or mineral surface. The multi-layer construction provides excellent waterproofing redundancy and solid resistance to foot traffic.

BUR systems are heavier than single-ply alternatives and require more labor-intensive installation, but they have a well-established performance record. They are still specified on some commercial projects, particularly where a proven, multi-layer barrier is preferred over a single membrane approach.

Metal Roofing

Expected lifespan: 30 to 50 years with minimal maintenance.

Metal roofing is less common on flat commercial buildings but is widely used on sloped commercial structures such as warehouses, industrial and manufacturing facilities, agricultural buildings, and some retail and mixed-use developments. Standing seam metal roofing, in particular, offers strong wind resistance, longevity, and low maintenance requirements.

Metal roofs can also be coated with reflective finishes to improve energy performance, and the the panels are recyclable at end of life. For buildings with steeper pitches where membrane systems are not appropriate, metal is often the most practical and durable option.

How to Choose the Right System for Your Building

Selecting the right roofing system depends on more than just upfront material cost. Key factors to evaluate include:

• Roof slope and drainage: Most membrane systems are designed specifically for flat or low-slope applications.
• Building use: Chemical resistance, rooftop traffic, and exhaust exposure all influence which materials hold up best.
• Energy goals: California’s Title 24 code sets reflectance minimums for low-slope roofs, narrowing the field for some projects.
• Budget and lifecycle cost: Consider total lifestyle cost; a less expensive system is the right call for some buildings, while others do better investing in a longer-lasting one.
• Existing roof condition: In some cases, a re-roofing system can be installed over the existing roof, which reduces tear-off costs and landfill waste.

A qualified commercial roofing contractor can conduct a full roof assessment, review your building’s structural and operational requirements, and present options with clear lifecycle cost comparisons.

Highland Commercial Roofing has served commercial property owners and managers throughout San Jose and the South Bay for 35 years. As an eight-time Guildmaster Award winner for Service Excellence, our team brings the experience and regional knowledge to help you select and maintain the right roofing system for your building. Contact us today to schedule a roof assessment.