Guide for Residential Flat Roof Materials

Throughout ancient history, flat roofs were favored for their simplicity and accessibility. Evidence of flat roofs can be found all over the world, from the Pueblo Indian culture in America to Mediterranean and Arab communities dating back thousands of years. In more arid climates where timber was not always readily available, flat roofs made home construction cheaper and less time-consuming. Meanwhile, these roofs made it possible for people to utilize the space on top of their houses for storage, gardening, or other needs.

Thanks to the discovery of improved roofing materials and construction techniques, flat roofs have risen in popularity in recent decades. Today, flat roofs are used in the construction of commercial, industrial, and residential buildings all over the United States. This flat roof guide will explore various types of flat roof systems, the differences between them, and how homeowners should maintain their flat roof to extend its lifespan. Read on to learn everything you need to know about how flat roof systems work and why spray polyurethane foam is rapidly becoming the flat roof material of choice for many.

What Is a Flat Roof?

Also called low-slope roofs, flat roof systems aren’t exactly flat. Instead, these roofs are built at a slight pitch that’s difficult to detect with the naked eye. This slight angle to the roof allows rain to flow freely from the roof edge, preventing water from pooling and potentially leaking into the home. Unlike a-frame and gable rooftops that often have attic space for storage, residential flat roof systems allow homeowners to utilize their roof for functional purposes like accommodating solar panels or installing a rooftop garden.

Common Types of Residential Flat Roofs

Flat roof systems have gone through many changes over the years. Today, there’s a wide selection of flat roof materials from which to choose, with each types offering its own advantages and downsides. Some of the most common types of flat roofs include:

Built-Up Roof (BUR)

These roofs have a long history in the U.S. dating back more than a century. A built-up roof is composed of multiple layers. First, a cover board is mechanically fastened to the existing roof deck. From there, several layers of asphalt and ply sheets are applied to create a water-tight barrier. Finally, roofers will add a layer of gravel or a reflective coating to help protect the layers beneath. While BUR roofs are relatively affordable to install, they can put a great deal of weight on a residential structure. In addition, the nature of BUR roofs can make it difficult to identify the source of roof leaks when they occur.


Ethylene propylene diene monomer or EPDM flat roofs first emerged on the construction scene in the early 1960s as an alternative to BUR roof systems. Essentially, EPDM roofs consist of a thin but durable layer of rubber secured to the roof deck with either adhesive or a ballast material like gravel. Although this material is easy to repair, EPDM roofs tend to puncture easily and they can be a little pricey compared to other flat roof options.

Metal Flat Roof

Residential flat metal roofs are usually made of aluminum and are especially effective at reflecting sunlight. Their reflective property helps to reduce energy costs for cooling during summer months. With that said, metal roof installation and repair can get quite expensive. Metal roofs are also prone to corrosion and multiple applications of protective paint may be needed throughout a metal flat roof’s lifespan.

Thermoplastic Membranes

The two types of thermoplastic membranes used in flat roofs today are PVC and TPO. These flat roof materials are made from various combinations of synthetic materials that are formed into thin sheets. Once spread into place on the roof, these thermoplastic sheets are often either heat-welded into place or secured mechanically at the seams. Thermoplastic flat roofs offer excellent protection against ultraviolet (UV) rays, oil, and chemicals, but like EPDM roofs, the smallest punctures in the material can lead to roof leaks. In addition, prolonged exposure to excessive heat can cause thermoplastic membranes to bubble or peel away from the roof deck beneath.

Spray Polyurethane Foam (SPF)

One of the newest residential flat roof options available today is spray polyurethane foam. Historically used to insulate attic spaces, this material is rapidly rising in popularity due to its moisture resistance and unparalleled energy efficiency. Once applied, SPF effectively creates a seamless barrier that can last for many years until any repairs are needed. This is because an SPF roof is installed all at once with no seams between sections, requiring no screws or mechanical fasteners that could potentially create breaches in the roof.

At American Foam Experts, our team has years of combined experience installing, inspecting, and maintaining residential SPF roof systems throughout California. Our spray polyurethane foam comes with a 15-year no-leak warranty and we offer competitive pricing on all our installations. In addition, it’s estimated that homeowners can save up to 50% on their heating or cooling costs by switching over to an SPF roof.

Rely on American Foam Experts for Exceptional Service and Quality Craftsmanship

If you’re looking for an alternative flat roof material to protect your California home, American Foam Experts can help. Our SPF flat roof systems provide superior protection against UV rays, rain, hail, heat, and other forces of nature that can rapidly wear down other flat roof options. Aside from its excellent insulating and waterproofing properties, our spray polyurethane foam emits zero harmful emissions and is 100% environmentally friendly. Not only that, installing a new SPF roof on your California home can be much more affordable than other options available on the market today.

Is your flat roof reaching the end of its service life and you’re tired of dealing with repairs? Contact our team of roofing specialists at American Foam Experts today to learn more about the benefits of an SPF roof system. Request your free quote today to receive an accurate cost estimate within 48 hours. We will walk you through the SPF installation process and answer any questions you may have along the way.