Commercial Roofing Systems – Key Considerations For Building Owners

When replacing a roof on a commercial building there are a lot of different factors to consider, from working out the logistics with the tenants, the roof materials best suited for the job, and energy efficiency, while all trying to balance budgets as well as quality while keeping in mind the maintenance costs.

In this article, we discuss what you need to know to help you make an informed decision when it’s time to replace your commercial property’s roof.

Commercial Roof Styles

Commercial roofs are generally classified into 2 types:

Steep Slope Roofs

Steep slope roofs are classified as any roof with a slope of 2:12 or greater. Steep slope roofs are favored because of the options available, such as asphalt shingles, clay or concrete tiles, or slate and fiberglass shingles. Steep slope roofs also shed water much easier making them more suitable for a variety of buildings, and withstand strong winds, rains, and high temperatures.

Steep slope roofs may require more preparation and roofers often need to stage the installation for the safety of the installation crew, and people on the ground as materials sliding off the building becomes a real possibility.

Low-Slope Roofs

Low-slope roofs are popular among commercial buildings such as warehouses, shopping centers, and stores. Flat roofs have the benefit of accommodating the installation of machinery and hardware, such as air conditioners, water heaters, and solar panels, directly on the roof.

Flat roofs do tend to hold water after rain and the engineering of the building has to design the roof strong enough to support the structure and possibly address the drainage issue with tapered systems as there is the risk that water may pool and cause damage.

Commercial Roofing Systems

After deciding on what slope will best suit your building and needs, it’s time to choose an appropriate roofing system. These are some of the most popular roofing systems for commercial properties:

Single Ply Roofing

The three most popular single-ply roofing systems are TPO (Thermoplastic Polyolefin), EPDM (Ethylene Diene Monomer), and PVC. All three of these roofs are usually associated with low-slope roofs and are characterized by being installed in a single-layer membrane that has a strong resistance to cracking and can be further categorized into thermoplastic membranes and thermoset membranes.

1. TPO​​​​​​ is composed of polypropylene or ethylene-propylene rubber sheets that are heat-welded together and can be attached with adhesive, mechanical anchors, or ballasts. TPO comes in multiple colors, with white, gray, and tan being the most popular, as these complement its natural heat-reflective properties. TPO falls under thermoplastic membranes
2. ​​​​​​EPDMs number one strength is its ability to resist heat and UV damage and is elastic enough to deal with impact from storm debris while still being low cost. EPDM is a synthetic rubber made from oil and natural gas.
3. ​​​​​​PVC roofs are a sandwich of two pieces of PVC “bread” on either side of a heavy-duty polyester reinforced lining. The topmost layer of PVC is often coated with additives to improve UV resistance while the bottom layer contains plasticizers to make installation easy.​​​​ PVC is longer lasting than its alternatives, offers increased fire resistance, and can be welded together for a completely watertight installation. PVC is considered the more aesthetically pleasing solution for low-slope roofs, and sheets can be recycled into new sheets when they reach the end of their lifespans.

Modified Bitumen

Modified bitumen roofs combine asphalt with a chemical polymer to create a roof that is flexible and temperature-resistant. Modified Bitumen roofs come in multiple forms that require different applications, such as self-adhesive sheets, hot mop, and torch applied.

These roofs are rated against multiple hazards, including fire, wind, and hail, which makes them ideal for buildings in hurricane zones.

Metal Roofs

Metal roofs are a classic choice for both commercial and residential. They are competitive and somewhat easier to install and offer both durability and a unique aesthetic. They are still one of the longest-lasting options available for sloped roofs.

Liquid Membrane Roofs

Liquid Membrane roofs are roofs that are constructed by pouring a resin over a reinforcing polyester lining. It offers the best waterproofing property of any roofing system and can be applied to any shape no matter how hard to reach or complex it is.

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