Most low-slope commercial roofing systems have three principle components:
Surfacing — surfacing is the component that protects the weatherproofing and reinforcement from sunlight and weather. Some surfacings provide other benefits such as increased fire resistance, improved traffic and hail resistance, and increased solar reflectivity.
If you’re in the process of constructing a new building, or planning the replacement of an outdated roof on an existing building, there are five main types of commercial roofing systems to consider:
TPO roofing systems are among the fastest growing commercial roofing systems. Made of an especially durable material with a low-temperature flexibility and a high-temperature tolerance, these roofs are exceptionally resistant to ultraviolet, ozone and chemical exposure. TPO roofs can be expected to have a lifespan of 20+ years, and also feature a high resistance to fire, punctures, chemicals and high winds.
EPDM roofing offers superior durability and versatility, making it one of the longest lasting types of commercial roofs available. EPDM commercial roofing systems are also typically easier to install, maintain and repair than most other types of commercial roofs.
BUR (Built-Up Roofing) System
A traditional built-up roofing (BUR) system derives its name from the building of a roof on-site using layers of base sheet, interply sheets and cap sheet or other surfacing such as gravel or liquid coating.
Hot asphalt (bitumen) is the bonding and waterproofing agent between layers. BUR is suitable for most low slope roofing applications. The higher the quality of the BUR materials and asphalt used and the greater the number of plies (and separate asphalt moppings), the more superior the roofing system.
APP and SBS modified bitumen
In the 1970s, technological advances in asphalt sciences led to the development of modifiers such as APP (atactic polypropylene)and SBS (styrene-butadiene-styrene) which, when added to unblown (unoxidized) asphalt, impart either plastic (APP) or rubber (SBS) characteristics. These additives provide enhanced performance characteristics to traditional asphalt. When coupled with reinforcements, such as polyester (superior elongation abilities) or fiber glass (high tensile strength), they create high-performance roof membranes.
APP modified bitumen membranes are self-adhering when heated using a roofing torch. SBS modified bitumen membranes can be formulated for torch application, but are more commonly applied using hot asphalt or cold SBS modified bitumen adhesive. The result is a BUR system with significantly enhanced performance capabilities. Continuing improvements in technology have also resulted in self-adhering SBS roof membranes.
When an SBS or APP cap sheet is combined with traditional BUR base sheets and interply sheets, the result is a hybrid roof offering the best of both systems – multiple plies and superior performance and longevity.
Photovoltaic Solar Panels
As energy costs continue to rise and America looks towards green and sustainable energy, many building owners are turning to solar energy roofing systems. PV solar panels installed over a rooftop or used with glass, membrane and roof-mounted tile, absorb sunlight and convert it to energy that can be used to power a building. Although not in wide use, PV panel roofs offer great potential to conserve energy and control skyrocketing costs.
Perhaps of all the types of commercial roofs available today, green roofing systems have experienced the greatest surge in popularity in the last few years. Sedum green roofs are typically flat roofs that are partially or completely covered with vegetation and soil and planted over a waterproofing membrane. Green roofing systems reduce the urban heat island effect by soaking up heat and also are found to dramatically improve a roof’s insulation value – lengthening the lifespan of the roof by as much as two to three times longer and saving on heating and cooling costs.
All of these commercial roofing systems are excellent choices for industrial, institutional and residential low slope roofing. In choosing, factors such as site access, structural load, finished appearance, desired warranty and performance criteria should all be considered. Your ADCO project manager can help with more information.