Types of Commercial Roofs

As a business owner, you need your livelihood to be protected. One of the most basic ways you can do that is with a solid roof over your place of business. Phoenix commercial roofing contractors know which are the best types of roofs, and for the most part, they’re broken into two categories: steep-slope and low-slope.

Steep-slope Roofing

As the name implies, these roofs have a steep slope and are designed for watershedding. To qualify, the roof needs to exceed a 14º angle. While we don’t necessarily need this type of roof in the Sonoran Desert, we still see roofs like this in the Valley of the Sun.

Types of steep-slope roofs include asphalt shingles, clay and concrete tile, metal roofs, slate, wood shakes and shingles, and synthetic materials. These roofs are usually applied in a shingle style, a piece at a time. These are built in three layers:

Roof deck: This is the structural beginnings of a roof and is usually a wood-based material such as plywood or oriented strand board.

Underlayment: This provides protection to the structure while the roof is being installed, and it also provides a second layer of weather protection once the final layer is added. It is sometimes referred to as felt or paper.

Roof covering: This is the final part of the roof, the one seen by the world.

Low-slope Roofing

Commonly used by Phoenix roofing contractors in Arizona, low slope roofs have less than a 14º angle. The low-slope systems, or membranes, fall into five categories: built-up roofing (BUR), metal panel, polymer-modified bitumen, single-ply, and spray polyurethane foam based (SPF).

Built-up roofing (BUR) is a tar and gravel roof. Phoenix roofing contractors use alternate layers of bitumen, typically coal tar or asphalt, and reinforcing fabrics to create a common membrane. The top layer is covered with rock and gravel, which holds the roofing materials like a ballast and prevents UV damage. Because of the slope, BUR systems require effective drainage to reduce water after rains. These roofs generally last 10–15 years.

Metal panel roof systems can be zinc, aluminum, stainless steel, coper, lead, tin, or some mix of any of those metals—and more. These are a go-to roof because they are low maintenance and have a long lifespan of 30–45 years when properly maintained. Because metal is susceptible to rust, these roofs must be treated with a protective coating that withstands sun and rain.

Polymer-modified bitumen sheet membranes are composed of reinforcing fabrics and hot polymer-modified bitumen in layers. They are usually installed as a two-ply system and can last up to 30 years. Due to the materials used, these are often referred to as rubber roofs.

Single-ply membranes come in two types: thermoplastic and thermoset. They are factory produced in a sheet. Thermoplastic membranes can be repeatedly heated and cooled; they soften when heated and harden when cooled. Thermoset membranes, on the other hand, permanently set when heated. These roofs last between 10 and 15 years.

Spray polyurethane foam-based (SPF) roofing is created by mixing and spraying a two-component liquid. The thickness of the roof can vary based on the desired slope and level of thermal resistance. Built in two layers, the first layer is rigid foam insulation and the second is a protective coating. Foam roofs can last 20 years with no coating and no maintenance, but when a protective coating is included, they can last the life of the building.

Which Roof Is Right for You?

So if you’re building a new commercial building or looking to replace your existing roof, there are plenty of choices. Which is right for you? Let the professionals at Gryphon Roofing answer that question.

Call us to schedule a consultation and protect your investment.