There’s often a misconception that liquid waterproofing is a recent development, but a combination of natural bitumen and various fillers, such as sand, was used to waterproof roofs as early as the 1820s. By the late 1800s, natural bitumen was being specified extensively, applied as a liquid with reinforcement layers using jute, straw, rag felt and other man-made materials.
Fast forward to the 1970s, and the benefits of bitumen coatings meant they were being used for a variety of waterproofing projects. However, this growth also began to trigger some negative perceptions of liquid manufacturers. Many products were being sold over trade counters to roofing contractors who were not applying them correctly or to the required specification leading to reports of failing roofs and subsequent bad publicity.
These issues were the drivers behind the launch of the Bitumen Roof Coatings Manufacturers Association (BROCMA) in 1979. The brainchild of Anthony Cobbold, the Chairman of Evode Roofing (now Hyflex Roofing), BROCMA was formed to help improve the sector’s reputation and develop initiatives that would raise standards of workmanship.
The association was reinvented as the European Liquid Roofing Association (ELRA) in the early 1990s, in-line with the growth in non-bituminous products. It also began to be recognised as an industry voice with an active role in drafting European standards. This included helping to write the European Technical Approval Guidelines (ETAG) for liquid applied waterproofing kits, with the association representing the UK alongside the British Board of Agrement (BBA).
In 2005, the ELRA evolved into the European Liquid Waterproofing Association (ELWA) to reflect the wider markets that liquid waterproofing was being used in such as car parks. As the liquids market continued to grow at pace, the association refocused to include roofing and re-launched in 2010 to become the Liquid Roofing and Waterproofing Association (LRWA).
The association now represents a total of 11 different technologies, including polymer modified bitumen emulsions, glass reinforced resilient unsaturated polyester resins (GRP), flexible polyesters, polyurethanes, poly methyl methacrylates (PMMA), methyl methacrylates (MMA), other acrylics, polyureas, thermoplastic block copolymers, hot applied polymer modified bitumens (hot melt), and silane terminated polyethers, one of the latest innovations in liquid waterproofing.
Every product has its place in the market and quality application is crucial. Ranging from highly specialised systems through to those sold through merchants, liquids are truly versatile as demonstrated by their use across a vast range of applications including roofs (domestic, large commercial and metal), car parks, balconies, walls, bridges and walkways.
This versatility has fuelled the expansion of the sector as highlighted by the LRWA’s research in 2017. This revealed that the liquid-applied roofing sector had grown by more than 30 per cent since 2013, making it the fastest growing part of the flat roofing market.
This growth has since continued as reflected in the LRWA’s membership. There are currently 27 manufacturer members compared to 16 in 2013. We also have associates plus a rapidly rising number of contractors, representing the fasting growing part of our membership.
History of Liquid Applied Membranes
The first liquid coatings used in a waterproofing capacity would have been natural bitumen and date back to biblical times. Boats were waterproofed using bitumen. Natural bitumen in conjunction with various types of fillers (sand etc) was used as roof waterproofing as early as the 1820s.
In the mid to late 1800s natural bitumen was in extensive use in roof waterproofing, the bitumen was being applied as a liquid with various types of reinforcement laid into the liquid such as jute, straw, rag felt and other man-made materials.
It was not until the 1910-1920 period that bitumen waterproofing moved into the factory.
Rubber technology was first used to produce coatings in the 1940s and with the addition of reinforcing fibres a strong waterproofing membrane was developed.
Between 1945 and 1955, various resin technologies were developed by several different manufacturers to improve the performance characteristics of liquid roof coatings and it is not long before the beginnings of the liquid waterproofing industry as we now know it.
In the 1960s and 70s, reactive acrylics, acrylic emulsions, styrene butadienes and unsaturated polyesters were developed and huge steps in improvements to the quality and durability of the liquid coating industry were seen.
In 1975 the first water based elastomeric roof coating was released on to the UK market.
The first BBA Certificate for the application of liquid systems on roofs was issued around 1975 demonstrating that liquid applied coatings provide durable, high quality roofing solutions.
Two component acrylic roof coatings were first used in the UK from 1978.
Providing greater UV stability, two component polyurethane roof coatings were launched in the UK in 1982 and two component unsaturated polyester roof coatings in 1983.
Solvent-based block copolymers coatings based on styrene- ethylene-butadiene were launched in 1985.
Single component moisture triggered polyurethane roof coatings were launched in the UK in 1987 removing the variability of mixing on site, reducing site waste and giving improved moisture tolerance.
The first BBA Certificate for GRP flat roofing was issued in 1988. This was the first recognition of the movement away from ‘general purpose or boat building’ resins towards systems designed specifically for the roofing market.
The early 1990’s saw further innovation in the polyester sector as flexible systems were introduced for direct application to a wider range of substrates.
During 1996 the first 25-year warranty systems were offered to the roofing industry for liquid applied systems further demonstrating the durability of liquid roofing systems.
European Technical Approval Guideline for Liquid Applied Roof Waterproofing Kits (ETAg 005) was endorsed in 2004 providing European-wide guidance against which quality liquid roofing systems can be compared.
Also during 2004, the first totally cold applied warm roof system incorporating all warm roof components and liquid applied membranes from a single supplier was launched. This brought the benefit of a single guarantee for the whole warm roof build-up.
In 2007 the first BBA Certificate for a complete cold applied warm roof system was issued further signifying the drive for quality in the liquid roofing market.