User:Waller42/Liquid Waterproofing

Liquid Roofing Liquid Roofing is the process of utilizing protective liquid roof coating systems in a waterproofing capacity on roofs. Liquid roof coating systems offer a highly durable waterproofing solution to new and existing roofs.

The History of Liquid Roofing
•	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 in to 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.

Applications & Benefits of Liquid Roofing
There are many benefits to using liquid waterproofing systems and there are literally millions of square metres to prove it.

Liquid waterproofing systems provide one of the most cost effective methods for making a new or existing roof waterproof. Correctly installed and maintained they can provide a long term life often in excess of 25 years. And in refurbishment situations liquid systems can provide savings of upto 70% on roof replacement costs.

Many manufacturers can offer liquid waterproofing systems for roofs, balconies, walkways and car parks, thus providing the benefit of a watertight surface that is also hard wearing.

Liquid Applied Waterproofing Systems offer a highly durable solution. There are many benefits which can be summarised as follows:

• Seamless • Fully bonded

• Cold applied systems

• Minimum disruption

• Ease and speed of installation • Cost effective

• Compatible with most substrates and easily detailed.

• Proven and guaranteed performance. • Long life.

• Technologically advanced.

• Range of specifications to suit all needs.

• Range of finishes including solar reflectives. • Availability of elastomeric systems.

Generic Types of Liquid Roofing
There are many types of liquid waterproofing membranes and the majority of them are covered by European Technical Approval Guideline 005 Liquid Applied Roof Waterproofing Kits. This provides an ideal basis for a system to describe the different type of liquid waterproofing membranes. There are some, however, that are not covered by the ETAG, but this should not detract from their use as long as they have a valid BBA Certificate for their intended use. Further information on these generic types can be found in Guidance Note No. 3 Generic Types of Liquid Applied Waterproofing Systems for Roofs, Balconies and Walkways and suitable applications are shown in the Product Selector. It is recommended that only systems holding current BBA Certification or ETAs should be specified.

Polymer Modified Bitumen Emulsions and Solutions
In these systems bitumen is modified with suitable polymers or co-polymers in order to enhance durability, flexibility and elasticity to the dried coating. These products can be supplied as waterbased emulsions or solvent based solutions. Water based products are normally applied in appropriate weather conditions as recommended by the manufacturer. In addition to bitumen and polymer modifiers, both the emulsion and solutions may also contain inert fibres and fillers. The products are designed for application by brushing or spraying or may be suitable for spreading. The systems may also require primers, reinforcements and solar reflective or protective finishes.

Glass Reinforced Resilient Unsaturated Polyester Resins
These systems are often referred to as GRP, glass fibre or fibreglass. They consist of a glass fibre reinforced polyester resin cold applied on site. The unsaturated polyester resins used need to be specifically formulated for roofing or balcony purposes to provide a combination of wear-resistance, flexibility, elasticity and fire performance. Pre-formed components usually referred to as GRP trims can be used to provide a fast, reliable and neat solution to finishing details.

Flexible Unsaturated Polyester Resins
These systems consist of an unsaturated polyester resin reinforced with a polyester fleece. They can be sprayed or hand-roller applied. It is recommended that only systems using unsaturated polyester resins specifically formulated for roofing or balcony purposes should be specified. The unsaturated polyester resins incorporated within the system must be specially formulated for roofing purposes to provide a high degree of flexibility and elasticity combined with fire performance.

Hot Applied Polymer Modified Bitumen
More generally referred to as Hot Melts, these products are based on hot applied polymer modified bitumen which is usually applied in two layers incorporating a polyester reinforcement. Due to the relative softness and tacky surface of the material a surface protection membrane is applied to the top coat. The protection membrane varies dependent upon roof usage and access required. The system can only be used as an inverted/buried roof membrane application or in roof garden/green roof design and therefore can only be used on roofs of up to 15 degrees pitch. The material is sensitive to UV light and at all upstands/details where the membrane becomes exposed a protective membrane must be applied to prevent UV degradation.

Polyurethanes
Polyurethanes may be single or two component, aliphatic or aromatic and cure/dry by reaction, or moisture trigger from latent hardeners, or by moisture cure from the air – possibly some of these in combination. They are formulated to give good fire performance and are highly resistant to UV light with aliphatic based product having better colour fastness. Whilst single component polyurethanes usually contain solvents, two component systems can be formulated solvent free. Reinforcement is used either locally or overall to produce tough, long-lasting systems; although unreinforced polyurethane is a very tough material in its own right and reinforcement may be added selectively.

Bitumen Emulsions and Solutions
In these systems either blown (oxidized) or unblown bitumen is supplied as waterbased emulsions or solvent based solutions. In both cases these products do not have added polymer modification. Water based products are normally applied in appropriate weather conditions as recommended by the manufacturer. In addition to bitumen, both the emulsion and solutions may also contain inert fibres and fillers. The products are designed for application by brushing or spraying. The systems may also require primers, reinforcements and solar reflective or protective finishes.

Water Dispersible Polymers
These products form a generic family which covers a wide range of emulsion or dispersion coatings, the common characteristic is a waterbased binder plus additives which dry via the coalescing process as water evaporates. They can be applied by airless spray, air-assisted spraying, roller or brush. The systems may also require primers, reinforcements and solar reflective or protective finishes. Water based products are normally applied in appropriate weather conditions as recommended by the manufacturer, but are highly waterproof once dry.

Additional systems
A range of resins for Liquid Applied Waterproofing Systems has evolved over the years, which are not covered by the existing ETAG (parts 2-8):

Methacrylates
Sometimes described as Acrylics, MMA or PMMA, these products are formulated to achieve the required physical performance by using various polymers dissolved in reactive methacrylate and acrylate monomers. These two-component, solvent-free products are generally applied by spray, although they can be formulated for roller, brush, trowel or squeegee applications. They cure by an extremely rapid in-situ polymerisation, which is activated by the addition of a peroxide catalyst. This curing proceeds rapidly even at temperatures around 0°C. All methacrylate coats chemically react with each other to produce a fully-bonded composite. The systems incorporate primers to ensure adhesion on a variety of substrates and reinforcement can be incorporated if required. The use of Bond Coats can allow them to be overlaid with asphaltic surfacing. On exposure to UV light, they display very good retention of physical properties. Although not specifically covered by the ETAG, some manufacturers have tested their roofing products against Part 4.

Acrylic Roof Coating Systems (Solvent Based)
A one component polymeric composition for use in repairing and coating leaking roofs, gutters and similar structures. They are particularly useful in an emergency repair situation in adverse weather conditions and will cure under water. Applied by roller or brush direct onto a clean, dust-free surface with any wide gaps being reinforced with glass-fibre tape. Most sound surfaces are suitable without a priming coat but priming is required on fresh bitumen, metal or asbestos.

Thermoplastic Block Copolymers (S-EB-S),(S-EP-S)(Solvent Based)
These are flexible single component systems which are applied to produce multilayer coatings. They can be spray, roller or brush applied. Internal reinforcement layers can be incorporated to increase the lifetime of the coating. Most sound surfaces are suitable without a priming coat but priming is required on fresh bitumen, metal or asbestos.

Market for Liquid Roofing
From the beginnings of the liquid market in bituminous solutions and emulsions, the liquid roofing industry has grown into a £multi-million market with products at the very forefront of waterproofing technology. Whether for refurbishment or new build projects, there are systems and products available that can be used in all areas of roofing, pedestrian areas, car parks and structural waterproofing.

Liquids are the fastest growing sector of the flat roofing market. LRWA members have seen roof area supplied and installed in the UK growing from 2005 to 2009 by nearly 70%, demonstrating the increased importance of these systems. With this substantial growth has come the opportunity for the development of suitable high quality ancillary products such as insulation, adhesives, trims and other components specifically designed for use with liquid systems.