commercial roofing pros and cons male worker picking up piece of roof

A Comparison of Commercial Roofing Systems—Process, Longevity, Pros and Cons 

 

Lots of options. Lots of variables to sort through. Lots of advantages and disadvantages. Lots of decisions to be made.  

 

When it comes to figuring out what type of roofing system is best for your commercial property, you’ve got plenty of things to work out. Attaining your best results involves having a detailed understanding of your people and business, knowing your physical location and type of facility, and analyzing the roofing systems available to you, including upfront costs and long-term warranties. When it comes to actually doing the job, use of top-quality materials and installation by qualified professionals is a must, as is performing both routine maintenance and taking care of immediate emergency repairs over the long haul.  

 

To help with all that, check chart for an overview of six common commercial roofing choices, along with a brief description of the processes, estimated longevity, and a listing of pros and cons associated with each one.  

Pros and Cons of Commercial Roofing Systems 

 

TYPE OF ROOF  PROCESS  PROS  CONS  LIFESPAN 
Built-up Systems  
 

BUR ‒ Built-up roofing 

Commonly called tar-and-gravel, roofs are built of multiple, alternating layers of bitumen (asphalt) and reinforcing fabrics, topped with a protective layer of gravel or stone. In use 100+ years, BUR offers well-proved effectiveness.  
  • Strong protection from UV rays increases energy efficiency of property  
  • Number of layers is adjustable to each situation, more layers = better protection  
  • Low maintenance is required over roof lifespan  
  • Good fire resistance built in 
  • Excellent for very large commercial properties, BUR is more affordable than newer, synthetic systems  
  • Installation is hot, messy, slow, labor-intensive, with hazardous materials, fumes, disruption of business activity 
  • Heavy materials add weight to building  
  • System can be susceptible to wind/water damage  
  • Leaks, tears are difficult to find, repair  
  • System is better suited to warmer than cold climates 
 

15-30 yrs. 

 

 

TYPE OF ROOF  PROCESS  PROS  CONS  LIFESPAN 
Built-up Systems (continued)  
 

Mod bit – Modified bitumen roofing  

Similar to BUR, mod bit has fewer layers, more adhesive options. Plys (layers) are sealed down to the roof deck or coverboard with no seams. Three different surfaces are available, mineral, foil, or laminate, with ceramic coating.  
  • System is strong, waterproof, airtight, tear-resistant  
  • Minimal maintenance is needed 
  • Mod bit is more affordable than newer, synthetic systems  
  • On-site installation is labor-intensive 
  • Dark color of materials absorbs heat, decreases energy efficiency 
  • Vulnerable to UV damage 
  • Supplemental coating is needed to improve energy efficiency 
 

10-20 yrs. 

 

 

 

TYPE OF ROOF  PROCESS  PROS  CONS  LIFESPAN 
Single-ply Membrane Systems 
 

EPDM ‒ Ethylene propylene diene monomer 

AKA rubber roofing, EPDM is a thermoset process using a membrane manufactured offsite with all ingredients incorporated into rolls of material. Chemically cross-linked polymers become rigid once applied. One layer of membrane is applied to the roofing substrate. Seams are sealed between membranes with mechanical fasteners.  
  • Rolls of membrane come in varying thicknesses to match material specifications to each property, situation  
  • Installation is easy since membranes are ready to place when delivered  
  • The system is not easily damaged by UV rays, is lightweight, durable, fire- and weather-resistant 
  • The membrane is resistant to leaks, punctures 
  • Seams between membranes can fail, allowing moisture leakage into building 
  • Finished membrane is black, looks like unfurled inner tube, and is not particularly aesthetically attractive 
  • While available, lighter colors are considerably more expensive  
 

15-25 yrs. 

 

 

 

TYPE OF ROOF  PROCESS  PROS  CONS  LIFESPAN 
Single-ply Membrane Systems (continued)  
 

TPO – Thermoplastic roofing  

Also a rubber-like membrane system, thermoplastic roofing is made of synthetic substances that soften when heated, harden when cooled, and can be reshaped over time. Seams are heat-welded, melted together for a dependable bond.  
  • Reflective white membrane repels sunlight, reflects heat, UV damage 
  • System resists corrosion, breakdown  
  • Seams are heat-welded/melted together for dependable bond  
  • Surface is resistant to mold, hail, fire, impact, air pollution, providing long-term durability  
  • Laminating of top layer, narrow width of rolls produce weak points that can shrink, crack, deteriorate, leak  
  • Fire-resistance is low, requiring integration of proper retardants  
  • Uneven quality of materials, variations in thickness lead to consistency problems  
 

7-20 yrs. 

 

 

PVC ‒ Polyvinyl chloride  

This is another type of thermoplastic system. Two layers of PVC material are reinforced with polyester plasticizers placed between plys to provide UV stability, flexibility, and prevent curling. Heat-welding keeps seams securely adhered together.  
  • Roofing is durable, flexible, energy efficient  
  • System is resistant to moisture, fire, pollution, wind 
  • PVC is well suited to fluctuating climates, varying natural settings  
  • Materials are recyclable, eco-friendly  
  • Upfront cost is higher than some other systems 
  • Membrane tends to shrink over time, pulling apart at seams, corners, causing leaks 
  • Older roofs may shatter, puncture, be difficult to repair 
 

15-30 yrs. 

 

 

 

TYPE OF ROOF  PROCESS  PROS  CONS  LIFESPAN 
Spray Foam Systems  
 

SPF ‒ Spray polyurethane foam  

A specialized system, SPF blends two chemical elements together under heat and pressure, forming a plastic that transforms from liquid to solid within seconds, expanding 30 times in volume as it dries. Once hardened, a fully adhered roof surface results. The foam must be covered with an elastomeric coating of silicone, acrylic, urethane, or butyl rubber and finished with a layer of crushed stone granules to prevent damage from UV radiation and other elements. Each roof is custom-created on-site and endlessly renewable with careful maintenance and regular elastomeric recoatings. 
  • Highest R-value of any roofing for energy efficiency that saves on both heating and cooling costs  
  • Expansion properties of foam make it self-forming around protrusions (no vulnerable flashings, fasteners, tape), formable to channel water and prevent ponding 
  • Gaps, nooks, crannies, overlaps are sealed to make roof water- and airtight 
  • System is lightweight, with good tensile strength 
  • Depth of foam can be increased for greater energy savings, weather-resistance 
  • Installation creates few business disruptions, can be installed over most existing systems 
  • Installation must take place in temperatures above 50 degrees, with low humidity, calm wind, in order for foam to form correctly  
  • Technicians must be properly trained, use highly specialized equipment for desired chemical reaction to occur  
  • Initial cost is higher than some other systems 
  • Elastomeric coating must be reapplied every 10 to 15 years to maintain integrity of system 
  • Semi-annual inspections, immediate repairs are recommended to correct issues from debris, foot traffic, weather, UV radiation  
 

25-40+ yrs. 

 

Male builder doing thermal insulation on roof of wooden frame house. Man worker spraying polyurethane foam on rooftop pros and cons of commercial roofing

It should be noted that costs vary widely and are subject to volatility. At this writing (December 2022) per-square-foot pricing ranges from $2.00 at the low end to $10.50 or more at the top. Always work with a knowledgeable, qualified professional to get the roofing system that works best for you.