Flat Commercial Roof

Understanding Flat Roof Types for Commercial Buildings

As we’ve often talked about in our commercial roofing-focused blog posts, it’s possible for your commercial building to have the wrong type of roofing system.

In buildings with flat roof structures (as opposed to low-slope or steep-slope structures), a “bad roof” can sometimes be installed. Most of the time, this is because inexperienced roofing contractors and novice building owners aren’t aware of all the decision factors that go into choosing the right roofing from the long list of possible options.

Perhaps more often, the type of business being conducted in a particular building changes throughout history. And while the original commercial roof may have been a perfect fit for the building’s earlier purpose, it could now be inappropriate—or maybe just too old.

No matter what, it’s essential to understand the fundamental properties of how your building’s flat roof is constructed so you can make more informed choices about preventative maintenance, repairs, and possible future replacement. Today’s post gives you a little insight into the popular flat roofing materials that might be up on your roof now, as well as how to determine whether you have the best roof for your business.

What type of flat roof is the best?

In short, this question can be difficult—maybe even impossible—to answer in broad terms. While there are plenty of commercial buildings of nearly identical construction located in areas with similar climate conditions, the business being conducted inside the building itself will often dictate what roofing system is best. (And, of course, additional factors such as an owner’s budget will influence the ultimate determination, too.)

For example, consider our recent project at Dawn Foods’ York, PA production facility. While the old ballasted EPDM roof that we replaced wasn’t totally unsuitable for the food manufacturing taking place underneath it, we worked closely with the customer to choose a different roofing membrane material that better addressed their unique business demands.

There are plenty of situations in which we might recommend the installation of one of the following types of roofing systems, as well.

Built-up Roofing (BUR)

One of the oldest commercial roofing types that still has merit in some new installation scenarios today is built-up roofing. BUR systems feature a continuous and semi-flexible membrane made of felt or fabric layers (called plies). The plies are alternated with layers of other asphalt-based materials like tar/bitumen and aggregate, which is the reason we sometimes refer to BUR as “tar and gravel” roofs.

BUR systems are relatively easy to repair and are extremely durable. However, they don’t offer reflectivity and are not as energy-efficient as the newer, more high-tech materials like single-ply membranes.

Thermoplastic Single-Ply Membrane Roofing (PVC & TPO)

As we talked about in-depth in our recent blog post about single-ply membrane roofing, PVC (polyvinyl chloride) and TPO (thermoplastic polyolefin) roofs offer the big benefits of reflectivity. These roofs are often white in color and offer high chemical resistance.

If you run a food production operation or a restaurant, PVC may be your ideal roofing system because it actively resists substances like oils and fats that may be exhausting onto your rooftop.

TPO and PVC roofing—like all single-ply membrane roofing—is installed by unfurling the rolls it comes in and then adhering the material to the roof deck. Unlike EPDM, which we will touch on next, TPO and PVC are typically adhered with heat to weld seams and make the roof waterproof. This two-step installation process may sound simple, but it is labor-intensive and requires professional experience to get right.

Thermoset Single-Ply Membrane Roofing (EPDM)

If you’re looking for a flat roofing material with both excellent fatigue and impact resistance—meaning it can stand strong against much of what Mother Nature hurls its way—EPDM thermoset roofing could be your commercial building’s perfect match. EPDM stands for Ethylene Propylene Diene Monomer, which is a rubber-like material. In fact, you may hear roofers calling these systems “rubber roofs.”

EPDM has an advantage in the industry with its “tried and true” technology—it’s been used by professionals for the last 40+ years. The best part? Some of those original EPDM roofs are still in service. The material is extremely durable, especially here in our Heidler Roofing home service area in the Mid-Atlantic US.

Since EPDM is black, the material is typically not reflective, but the introduction of light-colored ballast can influence how energy efficient it is.

Modified Bitumen Roofing (Mod Bit or MB)

Another system that may sometimes be called “rubber roofing,” is modified bitumen. Much like BUR, MB is a flat roofing material that is constructed in layers, although the petroleum-based substance between the plies provides a rubberized appearance and properties.

One of the significant benefits of MB roofing is its ability to handle regular foot traffic versus some single-ply membranes, mainly because it’s much thicker. It is also relatively easy to install compared to BUR or even EPDM, as it typically does not require the use of heat. Instead, much MB roofing is comprised of self-adhering “cold process” sheet material. It’s incredibly durable, but it’s not reflective, so those seeking the most energy-efficient flat roofing material should likely consider other systems.

Garden or Green Roofing Systems

While not installed very often due to the complexity and high expense factor—both initially and over the literal life of the roof—garden roofing systems offer amazing “green” benefits, especially in urban settings.

These beautiful and eco-friendly rooftop gardens consist of a multi-layered roofing system that both protects the building beneath it and supports living vegetation above. And, while you surely won’t see these being installed on many manufacturing or warehousing facilities, they are becoming more popular on buildings that house hospitality-based enterprises like restaurants and entertainment venues.

Heidler Can Help You Install Your Ideal Commercial Roofing System

So, how do you find the best possible flat roofing material that ticks all the boxes on your list of “must-haves”? The surest answer is to work with an experienced commercial roofing contractor who takes the time to listen to your needs and collaborate with you.

Here at Heidler Roofing, we are that contractor for business customers of all sizes throughout the Mid-Atlantic region. We take the time to learn about your concerns, what your business does or makes, your building’s construction, and—maybe most importantly—your budget to offer recommendations for roofing we’re proud to install. We also provide comprehensive preventative maintenance plans for all types of commercial roofing systems, whether we originally installed the roof or not.

Get in touch with us today to schedule your free initial roof inspection, and discover how our skilled craftsmen and legendary service make all the difference for your roof and your business.