Professional roofers installing a commercial roof.

When it comes to commercial roofing systems, commercial building owners often have a variety of options to choose from. These roofs can be layered, bolted on or sprayed on. They can be made of metal, plastic, or asphalt. Want to go green? You may be able to build an entire garden on top of your building!

Each commercial roof type has its own advantages and disadvantages. But, when it comes to the most common types of commercial roofing and which is best for your business, it’s important to balance factors like cost, life span, efficiency and disruption during installation.

Table of Contents

  1. Roof Angles: Low Slope vs. Steep Slope
  2. Flat Roof Roofing Materials
    1. Built-Up Roofing (BUR)
    2. Modified Bitumen
    3. Singly-Ply Rubber Roofing
      1. Thermoset Single-Ply
      2. Thermoplastic Single-Ply
    4. Green Roofing
    5. Liquid Applied Roofing Membrane (LAM)
  3. Sloped Commercial Roofing Systems
    1. Asphalt Shingles
    2. Metal Roofing Systems
  4. TEMA Covers All Commercial Roofing Systems!

Roof Angles: Low Slope vs. Steep Slope

It’s important to talk about roof slope before getting into the different types of commercial roofing systems, because systems can be divided into two main types: steep slope and low slope.

While steep slope roofs are mostly found on homes, they are also fitted to small commercial buildings. The angle of the roof helps precipitation slide off, away from the building. Large commercial properties, including warehouses, factories and big box stores have low slope or flat roofs. These roofs have to support the weight of snow in the winter while managing drainage. Often, these roofs also have to support equipment, including HVAC units, vents and solar panels.

Some commercial buildings use a combination of low and steep slope roofing. For example, an apartment or office building may have a steep sloped roof along the walls to keep vents and HVAC units from being seen at ground level. While this addition is purely decorative, both low and steep slope roof sections need to protect the building.

In the end, the slope ultimately determines which types of commercial roofing material works best.

Flat Roof Roofing Materials

If your building has a low slope (or flat) roof, you can often choose between several commercial roofing systems. Each has its advantages and disadvantages.

Built-Up Roofing (BUR)

Built-up roofing systems are made of several layers. First, a waterproof layer is attached directly to the insulation or cover board. Next, asphalt or adhesive is mopped onto the roof, followed by gravel plies or reinforcing felt. Several layers of alternating reinforcement and adhesive may be applied before finishing the roof with a top layer of asphalt and gravel or a cap sheet. Some cap sheets reflect heat, reducing the building’s cooling costs.

BUR is the oldest type of low slope roof construction, with decades of proven durability. They’re low maintenance and cost efficient, great at blocking UV rays and rank high in fire resistance ratings. However, it’s also the heaviest of all commercial roof types in use today.

Modified Bitumen

These commercial roofing systems are built by modifying asphalt with synthetic rubber and other components, then attaching fabric layers and soaking them in bitumen. This creates a hard-wearing surface that is resistant to foot traffic.

Two materials are used to make modified bitumen roofs: styrene-butadiene-styrene (SBS) roofing is elastic (so it can withstand severe temperature swings and impacts) and atactic polypropylene (APP), which offers excellent ultraviolet protection, increasing its useful life. Most bitumen roofing is made using twin ply construction. While modified bitumen isn’t as strong as BUR, it’s puncture resistant and weighs far less, allowing it to be used on a wide range of structures. This commercial roofing system is similar to asphalt shingle roofing.

Singly-Ply Rubber Roofing

Rubber roofing can be divided into two classes: thermoset and thermoplastic. The main difference between the two types is that thermoplastic systems have a lower melting point.

Thermoset Single-Ply

This type of roofing is made of synthetic rubber polymers that are cured, forming a durable, seamless membrane. Thermoset roofing is extremely popular on commercial flat roofs and low-slope roofs: the most widely known being ethylene propylene diene monomer (EPDM roofing membrane). It’s a single ply membrane that’s flexible in cold weather and also chemical resistant.

Thermosetting bonds plastic sheets to the roof, creating a single, uniform layer, and allows for a high degree of flexibility when it comes to design applications.

Thermoplastic Single-Ply

Two other types of single-ply roofing options are polyvinyl chloride (PVC roofing) and thermoplastic polyolefin (TPO) – both of which are thermoplastic systems.

PVC commercial roofing systems use sheets made from a light, UV-resistant PVC, a polyester reinforcement layer, and a darker PVC layer packed with plasticizers. This combination creates a flexible, tear-resistant surface. However, it can’t come in contact with asphalt, so it’s not an option on buildings that have used BUR or modified bitumen roofing.

TPO roofing is cheap, heat reflective and resistant to UV light, punctures and bacteria. However, it’s also prone to shrinking, so it doesn’t last as long as EPDM or PVC. All three roof coatings are weather resistant and have energy efficiency. They are also resistant to fats and oils, making them a great choice for restaurant roofing.

A major benefit of thermoplastic commercial roofing systems is that they are highly recyclable.

Green Roofing

There’s an evolution happening in the roofing industry – many industrial and commercial buildings are choosing to take a more environmentally friendly approach.

A green roof has a lot in common with an elevated garden bed. Both types of construction use a waterproof layer and a root barrier to contain plant life. This is topped by layers for additional protection and drainage to support the soil. The plant life on the roof can be chosen for minimum maintenance, use intensive agriculture to create a garden, or be something in between.

This option helps with stormwater management by soaking up some of the water runoff as well as insulation. It can also help combat high energy bills.

A green roof turns carbon dioxide into oxygen, reflects heat, increases local biodiversity, and absorbs storm water…all while reducing the building’s environmental impact. However, the weight of the soil and vegetation is far higher than a traditional roof, so it’s not always a viable option for some industrial buildings.

Liquid Applied Roofing Membrane (LAM)

A liquid applied roofing membrane is made from a combination of resin and polyester. This adhesive mix is sprayed or rolled onto the surface of the roof, creating a waterproof membrane as it dries. A primer layer may be required to get good adhesion. However, in most cases, the primer and membrane layers can be applied the same day, shortening project times.

LAM is available in a wide range of colors and is ideal for roofing with complex shapes and bonds to a wide range of materials, including steel, aluminum, bituminous roofing, and most types of roof membranes.

LAM roofing is cost-effective when it comes to roof replacement because it can be applied to existing roofing membranes. However, it can be quite stubborn to remove. It’s important to hire professional commercial roofing contractors to install not only LAM roofing, but any type of commercial roofing materials.

Sloped Commercial Roofing Systems

Steep sloped roofs refer to buildings with a slope of 3:12 or higher, and the slope of the roof line will ultimately affect the types of materials used.

Asphalt Shingles

While you might think of residential roofing when you hear the term asphalt shingle, this material is also widely used in commercial applications with steep slopes. Shingles are fiberglass-reinforced pieces that are soaked in asphalt. The surface is covered in granules, which protects each piece from the sun and debris. Keep in mind that shingles come in a variety of architectural styles, so it’s important to consider the design of your building when choosing your final look.

Metal Roofing Systems

Metal roofing solutions are gaining market share because they offer the longest life span per dollar spent. Steel is popular for flat roofs, thanks to its low cost and durability. Aluminum trades impact resistance for excellent corrosion resistance and low weight. Zinc and copper are expensive, but they develop a patina that is desirable for decorative roofs.

Metal roofing can be attached with visible or hidden fasteners, or it can be mechanically seamed, folding the edges together to create a uniform, waterproof surface. We install a range of Butler Manufacturing roof products, including their MR-24 standing seam system.

A metal retrofit roof is built on top of the existing roof. Since the old roof doesn’t need to be torn out, a retrofit can be more cost-effective and less disruptive than replacing the original roof. They also help with energy costs – when painted with a heat-reflective paint, energy bills can be slashed by 40%. Metal roofing is also great at resisting severe weather conditions like high winds.

TEMA Covers All Commercial Roofing Systems!

Tema Roofing Services has over a century of combined experience installing commercial roofing, and we offer numerous options to fit your needs.

Not sure where to start? Our design-build service covers every aspect of installation, including inspection, design, construction and project management.

Do you work for a public or private organization that requires cooperative purchasing? We work with partners including TIPS and OMNIA, making it easy to get new roof installations approved. Need to have your roof repaired or restored? We do that, too! Contact us today to get started.