Benefits of multi-ply roofing membrane vs. single ply

By admin on January 4, 2017 in Solutions for Facility Project Managers


The materials that comprise modern buildings have changed over the years to become lighter and more durable. Therefore, it only makes sense that the materials used to protect and insulate the core structure should adapt as well. For decades, asphalt has been among the most common substance used to cover the roof of many large structures, thanks to its waterproofing capabilities, light weight, low cost and ease of application. But traditional asphalt comes with some drawbacks too – constant exposure to large amounts of water can leave it cracked and prone to rapid aging. Traditional asphalt also warps significantly in either very hot or cold weather.

Without a way to not only enhance the asphalt layer but provide additional levels of protection, facility managers will find themselves spending an inordinate amount of time and money making repairs and replacements to roof materials. Some single-ply materials aim to solve issues with ordinary asphalt by acting as a total replacement, but these materials come with their own disadvantages.

The drawbacks of single-ply roofing can be easily avoided with a membrane system utilizing multiple layers of modified asphalt polymer bonded to a strong membrane. This method provides greater strength, flexibility and ease of maintenance compared to single-ply options.

Where traditional asphalt and single-ply falls short

Ordinary asphalt and single-ply roofing materials come with a number of drawbacks compared to the latest technology available:

  • Asphalt becomes more brittle with age, which presents problems due to natural shifting a building experiences over time. Although these shifts are too small to be seen, they add up over many years to crack brittle asphalt, thus exposing the roof to rain and sun.
  • Thin, single-ply roofing can be easily punctured by foot traffic or machinery, which may make movement on the roof difficult. This presents as particular problem in buildings that require roof access for maintenance.
  • Installation of normal asphalt involves a number of special safety precautions, and will release hazardous fumes into the air.
  • Some single-ply adhesives often comprise volatile organic compounds which might degrade quickly in the presence of certain chemicals, like cooking oil that is vented from kitchens.
Multi-ply roofing membraneSBS modified bitumen roofing systems maximize durability while keeping costs low.

Solving roofing problems

The shortcomings of single-ply and typical asphalt can be largely avoided by using roofing materials that combine multiple membrane layers sealed with an enhanced form of asphalt called SBS modified bitumen. The advantages of an SBS modified bitumen roofing system include:

  • Greater tensile strength and flexibility: Modified bitumen can withstand greater levels of fatigue for longer periods of time than asphalt, negating the need for constant maintenance to repair brittle roofing.
  • Multiple plies equals multiplied strength: Whereas single-ply roofing tends to break under pressure, using two or three layers of a compound like polyester offers more resistance to punctures and elongation. Multi-ply systems can be as thick as 300 millimeters, much more than even the thickest single-ply membranes.
  • Easy maintenance: The strength and flexibility of modified bitumen combined with multi-ply coatings means more than just greater resistance to foot traffic and the elements. It’s also much easier to repair and replace if a problem does occur.
  • Multiple application methods: Modified bitumen can be applied similarly to hot asphalt, but can also be installed with cold adhesive or heat welding in situations where the former would be impractical or unsafe.

Which roofing material is right for your building or facility? When it comes down to making this decision, the initial cost is only part of the equation. By choosing a high-quality roofing solution, it’s possible to see numerous financial and practical benefits.

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