The 5 Most Common Styles of Flat Commercial Roofing

Jan 9, 2020 | Roofing

There are numerous areas where commercial roofs differ from residential roofs, but one of the most important is their shape.  Commercial roofs are usually flat, unlike the steep slopes associated with most residential properties.  This causes commercial roofs to be entirely unlike residential roofs, in terms of both usage and construction. Different materials and construction techniques will bring different benefits over the years, ranging from energy efficiency to overall longevity.

The type of roof you choose will also affect your maintenance and operations, making it a particularly important decision. Here are some of the most common options for constructing a flat, commercial roof. 


The 5 Most Common Styles of Flat Commercial Roofing

1.  The Built-Up Roof

A built-up roof is constructed of several layers of material, which are then stacked one on top of the other.  These layers generally consist of a specialized felt that has been soaked in a binding agent and covered in asphalt.  Each additional layer adds more weatherproofing and insulation.  Finally, there is a cap sheet for the upper layer which is surfaced with gravel or slag to create a stable surface for walking upon.

BURs have traditionally been a popular choice due to being relatively inexpensive, as well as having above-average durability and insulative properties.  The primary drawback is that BUR-style commercial roofs are extremely heavy, and their low theoretical costs may be mitigated by the need for additional supports holding up the weight.

2.  Membrane Roofs

Roofs based around a synthetic plastic membrane are one of the fastest-growing areas of flat commercial roofing services.  These roofs involve the installation of a seamless layer of plastic, which is then heat-welded to a plain concrete roof. This membrane usually consists of either thermoplastic polyolefin (TPO) or polyvinyl chloride (PVC).  The resulting roof is generally white or otherwise light-colored, giving it excellent light reflectivity. This can be beneficial for commercial property owners looking to cut daily utility costs.  The single-ply, lightweight nature of membrane roofs also makes them attractive to businesses looking to keep construction costs low.  Membrane roofs offer exceptional energy efficiency and are also entirely water-impermeable.

PVC membrane roofs are always white and tend to be slightly more durable than TPO.  TPO, on the other hand, can come in different colors and is more environmentally friendly than PVC.  Either could make for an exceptional commercial roof.

3.  Single-ply EPDM

Ethylene propylene diene terpolymer (EPDM) is a synthetic rubber and another common alternative to roofs based on gravel or asphalt.  EPDM comes in sheets that are laid down on the roof.  Unlike membrane roofs, EPDM roofing is not seamless.  Adhesives are used to connect many sheets across the rooftop.  These seams are the most vulnerable part of the roof, and will likely need maintenance from time to time.

However, the tradeoff is that EPDM roofs offer exceptional weather protection – even against hazards such as hailstorms which would damage most other roof types.  EPDM roofs are most often seen in areas where adverse weather is commonplace.  Also, repairs to EPDM roofs are usually inexpensive, giving it a strong cost-benefit ratio when its overall damage resistance is taken into consideration.

4.  Asphalt Roofing

Asphalt roofs based in modified bitumen are one of the older forms of flat commercial roofing, but still popular due to their low install costs and good insulative properties.  These roofs are constructed from rolls of asphalt which has been bound to a rubber material, then adhered directly to the roof.  These roofs are single-ply and relatively easy to install.  Due to the ease in recycling and reusing asphalt, they are also considered environmentally-friendly.

Asphalt roofs are not as durable as other options and, in particular, cannot stand too much foot traffic.  However, they remain a good choice because of the low costs of the materials and installation often outweigh the increased need for maintenance over time.

5.  Roof Coating Systems

Coated roofs are a more recent invention and one which has also seen rapid adoption among businesses in need of a safe, affordable, long-lasting roofing solution.  Roof coating systems can come in many formulations but are generally a variation on rubber or silicone.  They begin as a liquid which is either sprayed or rolled directly onto the roof substrate, then smoothed out to create a single seamless surface across the entire roof.  This method of application makes them especially well-suited to roofs with unusual topography, such as a large number of vents and other features emerging from the rooftop.

Roof coatings can be formulated to meet a variety of needs, but they all tend to be light-colored and highly-effective at reflecting sunlight and UV rays.  The rubbery surface is also excellent at impact damage resistance, although it remains vulnerable to puncture damage.  They are also among the easiest of roofs to patch since additional coating material can be applied at any time to seal up holes, tears, or other damage.


Choose Durable Roofing for the best in commercial roofing materials & workmanship

When you are choosing a commercial or residential roofing contractor, experience matters.

Greenawalt Roofing Company is a Certainteed 5-Star SELECT ShingleMaster. By choosing Greenawalt Roofing Company for your roof replacement you are selecting a contractor in the top 1% of his profession who has met the most stringent credentialing requirements in the roofing industry. In other words, your home is in the very best of hands. Greenawalt Roofing Company has proven expertise in roof installations, is properly insured, and held to the highest standards of the program’s code of ethics.

Greenawalt Roofing Company is fully licensed and insured and we will provide a Certificate of General Liability and Worker’s Compensation for every job we perform.

Contact us today for a FREE estimate, 717-898-6000 or 610-779-3111!


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