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20/01/2017 16:03

Bitumen in roofing: Keeping you covered

To meet the diverse requirements of the roofing and waterproofing industries, consistent bitumen quality and effective logistics are vital factors.

The vast majority of the world’s bitumen supply – around 85 percent – is used in road applications. But bitumen’s properties also make it ideal for use in a wide range of applications. For example, Nynas bitumen is used to protect against moisture, sound, electricity and fire in materials such as pond linings, sound dampening panels, high-voltage electrical cables and wind barriers for buildings. In fact, after roads, the segment that uses the most bitumen each year – around 10 percent – is the roofing industry.

Bitumen roofing products can be applied using cold, soft or hot techniques. Cold and soft applied products dominate the marketplace. In Europe, soft-applied products, such as polymer modified bitumen membranes, are widely used in the low slope or flat roofing segment of the market.

An essential ingredient

The roofing industry spans a wide range of products that need to meet various requirements, and just as in the road industry, bitumen plays an important role in shaping the characteristics of the end product in diverse applications.

A bitumen roofing membrane usually contains limestone filler and a very high proportion of bitumen – around  65-70 percent. Low-temperature flexibility, heat resistance, the ability to withstand ageing and fire retardancy can all be affected by bitumen choice. Moreover, it represents the main mechanical characteristic of the membrane, making it a key factor in the processability of the end product.

As the roof is the most exposed part of a building, it must be able to withstand tough conditions, from rain, wind, snow and ice, to heat and sunshine on summer days. To achieve greater durability, polymers are often added to bitumen roofing membranes. Bengt Sandman, Product Application Specialist, Hot Mix and Industrial Applications, Bitumen Nordic, Nynas, explains: “The advantage is that the polymer modification increases the bitumen’s elasticity at both low and high temperatures and results in increased joint strength. Polymer modification also makes it possible to use softer bitumen and therefore improve the ageing resistance while still maintaining good low temperature properties.”

Teaming up for success

Given the significant influence that bitumen has on the qualities of the end product, it is essential to have a high quality, stable bitumen supply to achieve product consistency. Marc Hannes is Director of DeBoer Waterproofing Solutions, a producer of bituminous membranes in Belgium. He explains the benefit of having access to bitumen of a consistent quality. “Our aim is to always work with a partner that is trying to achieve a stable quality. If we have bitumen that is stable from the start, we don’t have to alter the polymer modification recipe, and our clients feel they are always getting the same quality.”

Supply security and reliability are other important factors, and for this, efficient logistics are a must. Getting the right product at the right time and at the right temperature is a crucial requirement for customers. “It is important that when the truck arrives the temperature is still high enough to unload in an effective way. If the temperature is too cold, it’s too difficult to unload and we have to heat it up before we can use our polymers. So reliable logistics is important,” Marc Hannes adds.

Moreover, to ensure that products meet changing future demands, innovation is needed. “There is innovation taking place in our industry and what you can do with bitumen you cannot always do with synthetics. Bitumen is an important part in our product and it is always of interest to have good technical support from our supplier,” affirms Marc Hannes.

Further reading

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