Why PVC (Vinyl) is the Sustainable Roofing Solution

Rising temperatures and prolonged heat waves are fast becoming the key challenge for our cities and urbanized areas. A white PVC commercial roof can reflect 80% or more of the sun’s rays and emit at least 70% of the solar radiation a building absorbs. Regardless of climate, when the sun beats down, a cool roof will counteract the effects of heat islands formed by heat-absorbing surfaces – dark roofs, concrete, pavement and parking lots – to keep ambient temperatures low.

Why does the cool roof effect work? In full sun, the surface of a black low-slope commercial roof may experience a temperature rise of as much as 50 to 90 degrees, reaching midday temperatures of 150 to 190 degrees in summer. A white PVC roof on the same building typically increases only 10 to 25 degrees above ambient temperatures, lowering surrounding air temperature and reducing smog formation.

In addition to building resilience and improving the quality of the urban environment, the long service life of PVC roofing membranes – combined with recyclability, relatively low use of non-renewable resources, inherent energy efficient characteristics, and suitability for green roof assemblies – make them the sustainable choice among commercial roofing systems.

The reflectance, emittance and solar reflectance index criteria for LEED, ENERGY STAR, Green Globes and California’s Title 24 all can be met when a commercial building uses a reflective PVC roofing membrane. White PVC roofs achieve some of the highest reflectance and emittance measurements of which commercial roofing materials are capable.

An asphalt roof only reflects between 6 and 26% of solar radiation, resulting in greater heat transfer to the building interior and greater demand for air conditioning – a strain on both operating costs and the electric power grid. Net annual energy savings are typical even in northern climates. Cool roofs can have more impact on energy cost than energy use, cutting consumption during peak power demand when the rates are the highest and offsetting any minimal wintertime increases in use when there is less sunlight to reflect.

Other sustainability benefits of PVC roofs include:

• LONG SERVICE LIFE – The first hallmark of sustainability is to put on a roof that lasts a long time. While all products have environmental impacts resulting from manufacturing and shipping, durable PVC roofing membranes have a long service life that is second to none. Many PVC roof systems have been in service in excess of 30 years.
• RECYCLABILITY – Manufacturing scrap from PVC roofing membrane has long been recycled into new accessory roofing products. But PVC is the only commercial, sustainable roofing material that is being recycled at the end of decades of service life into the feedstock to make new membranes.
• COMPATIBILITY WITH GREEN ROOFING COMPONENTS – PVC can be a component of building integrated photovoltaic (BIPV) solar electric roofing systems because the material’s proven long lifecycle, high reflectivity, superior fire ratings and hot-air welded seams assure that the roofing substrate will function as long as the PV modules. PVC roofing membrane is also used in concealed applications such as the waterproofing layer in planted roofs. The permanent hot-air welded seams do not deteriorate in the perpetually moist environment of a green roof, and those same seams provide the highest resistance to root penetration of any waterproofing membrane.
• LOW EMBODIED ENERGY – When compared to other commercial roofing materials, less energy is needed to produce the PVC resin and process it into the end product. Most alternatives have far more embodied energy.
• COMPRISED OF RENEWABLE RAW MATERIALS – 57% of PVC resin is derived from salt. Less oil is consumed to produce PVC than in the production of base materials for any other single-ply roofing membrane.

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