Single-Ply vs. Built-Up Roofing Systems: Pros and Cons

Introduction to Low-Slope Roofing Options

When it comes to low-slope or flat roofing systems, two of the most common solutions are single-ply and built-up roofing (BUR). Each system offers its own set of strengths and challenges, making the choice dependent on your specific project goals, climate, and budget. Understanding their differences can help you make a smart, long-term investment for your commercial or residential property.

For building owners in Santa Monica, CA, selecting the right roofing type is crucial. The coastal climate, with its salt air and occasional heavy rains, requires a roof that can withstand moisture intrusion while providing long-lasting durability.

What Is a Single-Ply Roofing System?

Single-ply roofing systems consist of a single membrane layer, typically made from TPO (Thermoplastic Olefin), PVC (Polyvinyl Chloride), or EPDM (Ethylene Propylene Diene Monomer). These membranes are either mechanically fastened or adhered directly to the roof deck.

Advantages of Single-Ply Systems

• Lightweight and Flexible: Easy to install and works well with varied roof shapes.

• Energy-Efficient: Reflective white membranes can reduce heat absorption, lowering cooling costs.

• Fast Installation: Ideal for time-sensitive projects.

• Chemical Resistance: Especially true for PVC and TPO, which resist pollutants and UV degradation.

Limitations of Single-Ply

• Puncture Risk: Thinner membranes can be vulnerable to damage from foot traffic or sharp debris.

• Adhesive Sensitivity: Proper adhesion is critical, especially in areas prone to wind uplift or excessive rain.

What Is a Built-Up Roofing System?

Built-up roofing systems are made by layering bitumen (either asphalt or coal tar) with reinforcing fabrics in alternating sections. Once assembled, the surface is finished with a protective top layer, such as gravel or a reflective coating.

Benefits of BUR

• Durability: Multiple layers provide robust protection against water and mechanical damage.

• Excellent Waterproofing: Built-up systems are known for their redundancy in waterproofing capabilities.

• Proven Performance: BUR has been in use for over a century and has a well-documented track record.

Drawbacks of BUR

• Heavier System: Requires a reinforced structure to handle the added weight.

• Longer Installation Time: Can increase labor costs and project duration.

• Odor and Fumes: The installation process can release strong odors and requires safety precautions.

Comparing Cost and Longevity

Single-ply roofs generally cost less to install than BUR systems due to fewer materials and a quicker installation process. However, BUR systems may offer longer lifespans in harsh environments due to their layered construction.

In Santa Monica’s salty, humid climate, both systems can perform well when installed and maintained properly. The best choice often depends on whether you prioritize ease of installation or multi-layered protection.

Choosing the Right Brand and Installer

Both systems require materials from trusted brands to ensure long-term success. Malarkey, Owens Corning, and Polyglass offer a variety of products suited for single-ply and built-up applications. These brands are recognized for their durability, energy efficiency, and warranty support.

Equally important is choosing a contractor with local expertise. Economy Roofing is well-versed in the specific demands of Santa Monica roofing and can recommend the best system based on your building's structure, usage, and exposure to the elements.

Which System Is Best for You?

If your priority is a quick, affordable solution with reflective energy-saving benefits, a single-ply membrane may be ideal. For maximum waterproofing and durability, especially for buildings with heavy equipment on the roof, built-up roofing offers time-tested protection.

Regardless of the system you choose, regular inspections and maintenance are essential to preserving roof performance and extending its service life.

Read also our blog: Comparing Galvanized and Painted Metal Roofing