BUILT-UP ROOFING (BUR):
Built-Up Roofing has been in use for more than 170 years, and was originally referred to as "composition roofing". In this type of roofing system, a waterproof base sheet is first applied to the cleaned and prepped roof deck. Then, multiple layers (traditionally, 3-, 4-, or 5-plies) of roof "felts" are adhered together with a bonding agent, such as asphalt or coal tar. Finally, a protective surfacing layer is applied to complete the process. As one can surmise, the more intermediary layers that get applied, the greater longevity that the roof is expected to provide.
EPDM (Ethylene Propylene Diene Monomer):
EPDM roofing systems have been in use for about 50 years and, throughout that time, they have been successfully employed as a waterproof roof covering. For those ecologically conscious folks among us, you should note that EPDM does not in any way pollute the runoff rainwater. This is clearly a benefit to the property owner who wishes to use the water runoff for gardening, personal sanitation, or hygiene purposes. EPDM offers the user ease of installation, increased durability, and versatility of design.
PVC (Polyvinyl Chloride):
PVC roofing systems have been in use for about 40 years, and they currently account for about 10% of the roof coverings in America. They are extremely durable, highly resistant to punctures, dirt, and debris. PVC systems are waterproof and they are often used in "green" roofing settings, where plants, trees, and shrubs are planted and incorporated into the roof's "landscape". This very flexible material allows for use on nearly any shape of roof, and it is basically maintenance-free. Due to the chemical make-up of PVC roofing systems, they are also fire-resistant and energy-efficient.
SBS-MODIFIED (Styrene Butadiene Styrene):
SBS-modified roofing systems are highly favored in climates with greater extremes in both Summer and Winter temperatures. By adding SBS to a basic roofing sheet, the result is a product with greater pliability and flexibility. Fibreglas and polyester are just two of the materials used to reinforce SBS roofing systems, and materials such as these give the product greater elasticity which, in turn, provides for a faster "return to normal" after experiencing the aforementioned temperature extremes.
TAPERED INSULATION SYSTEMS:
Tapered insulation systems are designed to provide the slope that is lacking on flat roofs so that proper drainage can then occur as desired, thereby extending the life of the roofing system as a whole.
As architects, structural designers, and roofing professionals have gained greater understanding of how standing water and improper drainage can have a negative impact on both new construction and existing roofing, tapered insulation systems have truly come to the forefront in terms of their utilization and need. Many construction-related regulatory agencies now recommend or even require designated minimums for roof slopes on both new roof construction and existing roofs.
TPO (Thermoplastic Polyolefin):
Currently, one of the fastest growing products for use in commercial roofing is TPO (or, thermoplastic polyolefin). Throughout the roofing industry, TPO roofing membranes have many advantages, both in terms of installation and performance. As the world continues to focus on roofing systems that are energy-efficient, TPO roofing systems resist ultraviolet, ozone and chemical exposure levels in significant amounts.
TPO membranes are environmentally friendly, and their flexibility makes them highly durable and resistant to punctures. These membranes are usually laid across the roof, and then secured in one of three ways: "fully adhered" means that an adhesive is applied to the roof's surface prior to the TPO being placed atop it; "mechanically attached" means that the TPO is secured to the roof's surface using some type of screw; "ballasted" means that the TPO is laid across the roof's surface before being weighted down with rocks, gravel, or similar materials. TPO roofing systems have been in use for over 10 years. TPO roofs are gaining in popularity for new construction and as the replacement roof of choice.