A waterproofing solution as simple as it is efficient - Building NZ
A waterproofing solution as simple as it is efficient

A waterproofing solution as simple as it is efficient

Waterproof sheet membranes are often the go-to option when waterproofing a surface, but they have several disadvantages. Spray-applied waterproofing solutions are an attractive alternative — especially since they can be applied over existing roof membranes.

Words by ArchiPro Editorial Team

Food, water, clothing and shelter are generally accepted to be the four fundamental human needs that are imperative for survival. As a , and is of greatest concern when it comes to the construction and architecture industry.

To qualify as ‘shelter’, a structure must protect us from exposure — the heat, the cold, and the weather. And as a country with a largely temperate climate, for construction in New Zealand, it’s paramount that every building or structure gets its waterproofing right.

Traditionally, one of the most popular and enduring methods of waterproofing a roof, for example, is the installation of a waterproof sheet membrane — a layer of water-tight material that is physically laid onto the surface.

While these kinds of solutions have a time and place, there are some notable disadvantages: the product needs to be cut and pieced together to suit the size of the space, which can result in seams and changes of plane, and it’s labour intensive to lay down.

This is to say nothing of the fact that such membranes are not suitable for installation in certain scenarios, where it can be hard to reach or service.

This is where spray-applied waterproofing solutions present themselves as an attractive alternative, says MBP National Product Manager for Waterproofing Systems, Jeffrey Perrett.

“As an alternative to sheet membranes, spray-applied have many benefits,” says Jeffrey. “You can apply it in these hard-to-reach places, and crucially, you can also apply it over existing roof membranes — either as a fix for an end-of-life membrane, or to reinforce it.”

The MAPEI Purtop 400M - simple and effective

One of the most effective and prominent spray-applied waterproofing products in New Zealand is the MAPEI Purtop 400M offering — and as the sole distributor of MAPEI products in New Zealand, MBP is well-versed in the multitude of applications and advantages that it offers.

The Purtop 400M is an instant curing, fast turnaround spray applied waterproofing coating system that features high bond and mechanical properties. It can be applied in situ using a high-pressure, bi-mixer type pump to form waterproof and protective coatings on bridge decks, roofs, planter boxes, below ground structures and more.

Its fast-curing properties, in particular, are a prominent feature in its list of benefits, as traditionally, similar spray-applied products required a significant delay for it to dry. The Purtop, though, is fully serviceable in a few minutes, Jeffrey says.

“The product cures rapidly,” he says, “so depending on the project, you can get the spraying done, as well as a topcoat, finished in a single day.”

This obviously helps keep projects up to speed and to strict deadlines, but it also alleviates the amount of manual labour and niche expertise needed to lay a waterproof sheet membrane.

Monolithic, seamless and speedy

It also eliminates the drawback of seams that are common in traditional sheet membranes. “It’s monolithic,” says Jeffrey. “There’s no joins or seams — so it’s a continuous, monolithic, literally seamless finish.”

It’s also versatile — it not only keeps water from ingressing, but it opens the door for the surface to be utilised in a plethora of ways. Surfaces treated with the Purtop 400M solution are ‘trafficable’ — meaning they are suitable to be used as parking lots, for example in multi-storey car parks; or high foot-traffic areas like stadiums or public transport hubs.

Jeffrey also affirms that the product is suitable across all areas and climates of Aotearoa. “We get many people who ask, ‘will it work in cold areas where it snows, like Canterbury, Otago and Southland?’ And yes, this product is fully functional and serviceable in all parts of the country, in all weather conditions — from Alexandra to Kerikeri.”

But above all these standout advantages that the Purtop offers, Jeffrey finds that there’s one that often stands out delivering more value than all the others.

“The biggest benefit of this product is the time that it saves,” he says. “In an environment where all construction projects are working against the clock, on a very tight schedule, a product like this one is a breath of fresh air because it can be installed and serviceable so fast.”

For all these reasons and more, it’s definitely something to consider, says Jeffrey.

Learn more about MBP and the MAPEI waterproofing products that it offers.

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