An ancient product with modern prowess - Building NZ
An ancient product with modern prowess

An ancient product with modern prowess

Mastic Asphalt has been used since the 1700s as a waterproofing construction material. It’s a unique product that, despite hundreds of years of technological advances, has not been surpassed in its waterproofing ability. While there are alternatives, all have their drawbacks compared to this age-old product.We chat to Neuchatel Limited about its history and benefits in contemporary construction.

Words by ArchiPro Editorial Team

The waterproofing properties of Trinidad Lake Asphalt, the basis of Neuchatel Mastic Asphalt, was first discovered by Sir Walter Raleigh in the 1700s who used it to waterproof his fleet for the journey back to the old world. Over the centuries, its use has exploded into all facets of construction and today, it’s still the most favoured option for waterproofing, especially for roofs, decks, carparks and high-rise buildings.

“Although it has been refined over the years, it’s still essentially the same product that was first used back in the 1700s,” Neuchatel’s CEO, Brian Mohan says. “Today, there are more complex polymers added to optimise the products for specific uses such as on roads and carparks.”

Mastic Asphalt, when applied correctly, is completely impervious to water and will usually last the lifetime of the building. “When you pour mastic asphalt, it’s a very viscous liquid so it creates a single layer which is totally impermeable to water,” Mohan says. “The viscosity of the material even after it has set, absorbs vibration and movement without cracking, which is a distinct benefit compared to rigid alternatives.”

Under Paving Waterproofing 

Mastic Asphalt is derived from only a few sources in the world, and Trindad Lake Asphalt in particular is renowned for it’s quality and purity. Once refined, this translates to high quality products, which are both effective and robust as well as extremely durable. For Mohan, it was a delight to be called in by the owners of a building to replace the original Neuchatel Mastic Asphalt waterproofing that had been installed 70 years earlier. “It was still performing effectively despite being well past its recommended lifespan.”

Although commonly used for waterproofing renovations, mastic asphalt is also used to achieve a watertight seal on new projects too. Auckland’s Aotea Square, for example, has a layer of mastic asphalt underneath the paving to protect the underground carpark that sits below it from water.

While there are alternatives to mastic asphalt that are commonly used, each have their drawbacks, and – for the most part – are derivatives of mastic asphalt anyway. Torch-on bitumen membranes are perhaps the main alternative. “While these are sometimes cheaper, it’s much harder to create a seamless waterproofing layer, especially if there is piping or ducting to worry about. With Mastic Asphalt this is a given because it will adapt to the contours of the job and there are no seams or air pockets that could attract water over time so the entire surface becomes one impenetrable sheet.”

More recent developments in mastic asphalt technology have led to the development of special-purpose products like Permapark, which is designed specifically to cope with the high traffic loads and hot sun of open-air carparks. In contrast, Permatrack is designed for road repairs.

Under Paving Waterproofing 

Neuchatel has specialised in residential and commercial mastic asphalt aplications in New Zealand for a century and is one of the country’s longest running construction businesses.

Get in touch with Neuchatel on ArchiPro here to discuss the waterproofing requirements of your next project.

Neuchatel Carpark Waterproofing Membrane
Recommended reading