Why specify PMMA liquid technology?

Gary Hemmings, managing director of WestWood Liquid Technologies, explains how PMMA technology is meeting the need for more aesthetic and durable waterproofing across multiple applications.  

Polymethyl Methacrylate (PMMA) liquid-applied systems were first developed by chemists in 1928 and have been benefiting the construction industry for decades. Yet, ongoing research, development and investments have seen the technology advance in recent years, making it more versatile and effective than ever before. 

Offering strength, flexibility and superior aesthetics, PMMA systems are suitable for a vast range of applications. As well as waterproofing roofs and balconies, they can be used for refurbishing car parks and infrastructure such as roads and bridges. The durability of the technology also lends itself to new build work as well as more specialist projects ranging from swimming pools, fountains and spas through to industrial kitchens.  

Maximising Speed and Durability

Solvent free and cold applied, PMMA systems are compatible with most substrates and usually comprise at least two components – the resin and a catalyst or activator. Contractors will mix the components together on site, starting an exothermic reaction, which initiates the curing process.

As part of the installation, a polyester reinforcing fleece will be saturated with the PMMA resin, bonding the membrane to the substrate. The surface layer is then applied onto the embedment coat while still wet forming a single, seamless membrane of uniform thickness.  

Compared to other liquid technologies, PMMA is one of the fastest curing. The process can take as little as 15- 20 minutes even at sub-zero temperatures, minimising disruption in occupied sites and the risk of any delay to construction schedules. In practice, this means a balcony could be refurbished in just a day or a car park ramp reopened to vehicles within just a few hours.

When installed correctly by an approved contractor, the PMMA build-up can offer a long-lasting solution guaranteed for up to 25 years. The chemical structure of PMMA means it is free from plasticisers and has a high tensile strength and elasticity. This ensures the membrane can withstand structural and thermal movements and is highly resistant to UV radiation. 

Adding Colour and Functionality

For architects, another key benefit of specifying a PMMA system is the superior aesthetic finish that can be achieved. A vast range of colour options offer full design flexibility for both interior and exterior spaces.  Bright vibrant shades can be used to create an eye-catching appearance or functional benefits such as easier orientation in multi-storey car parks.  For domestic properties, a variety of natural colours help to convey warmth while shades of grey can create more intensity for architectural projects, including public spaces.

Adding further design flexibility, it is possible to match a PMMA system to any RAL colour and a variety of special finishes can be achieved to meet a range of aesthetic requirements. These include modern tile effects as well as more intricate patterns that reflect traditional architecture.

As the cured system is UV resistant, aesthetics are maintained as there is no risk of the membrane fading after the installation is complete.

A Perfect Match

A unique waterproofing project, involving an impressive structural piece of art, demonstrates the qualities of PMMA liquid-applied systems. 

Named ‘The Wedding Cake’ the art was designed by renowned Portuguese artist, Joana Vasconcelos and commissioned by the Rothschild Foundation as a celebration of love, festivity, and joy.

Standing 12 metres high, the ceramic sculptural pavilion is inspired by Baroque architecture and traditional ceramic traditions of Lisbon. Incorporating the sounds of trickling water, it features thousands of ceramic tiles glazed in delicate shades of pink, green, and blue, reminiscent of icing on a cake. 

The steel modular structure was shipped to the UK and subsequently constructed by Westgreen contractors. A PMMA system was specified to waterproof stairways on three levels of the structure as well as the walkways and terrace areas around the ‘cake’. This ensured each level of the cake-shaped pavilion was watertight, including step access, flat areas, and gullies for rainwater drainage.

The comprehensive waterproofing solution included a customised non-slip wearing course also manufactured using PMMA and developed specifically for heavily trafficked areas. To maintain the artistic integrity of the structure, it was crucial that this coating complemented the appearance of the delicate porcelain tiles that feature throughout the artwork.

Thanks to meticulous colour matching, the PMMA coating was manufactured in the yellow, pink, green, and blue pastel colours required ensuring the structure aligned aesthetically with the artist’s vision.

The installation showcased the ability to seamlessly integrate art and practicality, transforming a unique concept into a functional and visually stunning public attraction.