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48 | J U N E 2 0 2 3 Waterproofing P H OTO G R A P H Y CO U RT E S Y F L E X S TO N E; K RY TO N I N T ER N AT I O N A L I N C .; EN G I N EER ED S I T E P RO DU C T S Sundecks in residential, commercial, and even industrial facilities are as susceptible as roofs to the damage caused by the elements, but Flexstone deck coatings continue to gain favour as the best alternative to traditional membranes. Their desirability starts with the manufacturing process: Flexstone is formulated to handle vehicle traffic and dramatic temperature fluctuations. This contributes to the product being long lasting – on residential sundecks Flexstone can easily last up to 30 years before repairs or a new topcoat is needed. All the components of the Flexstone system are designed to flex together, so movements and shifts in a deck won't cause cracking or leaks. Also, unlike tra- ditional membranes, if part of the four-ply CCMC approved rubberized coating is damaged, the fix is easy: just sand the damaged area, wipe down, and apply a new coat. Yet another benefit of Flexstone is aesthetic appeal. A variety of finishes are available to suit nearly any design scheme (the mock-aggregate finishes also act as tough but flexible outer shells that keep the underlying membrane safe). One of the main challenges faced by Glade Schoenfeld, a professional engineer in the building science and restoration practise of RJC Engineer's Vancouver office, is impressing clients about the critical role maintenance plays in the ongo- ing ability of any system to provide efficient waterproofing. "Rooftops in strata developments are a great example, especially roofs that double as rooftop gar- dens," he says. "Plants with aggressive roots such as bamboo are popular because they tend to grow fast and are very hardy but super-aggressive roots can easily destroy waterproof membranes within a few years." "I've even seen a root ball of a beautiful 35-year-old rhododendron plant that had grown entirely under a roof membrane destroying it in the process. The fact is if any tree or plant grows too big, it spells trouble – and pulling them all out and replacing with new growth is not only costly, but in residences it can cause problems with homeowners because their view changes or the privacy provided by the mature planting gets removed." That's why Schoenfeld and his colleagues spend considerable time during the planning stages of new developments and renewal projects working with landscape architects to advise on appropriate ways to 'green' areas that must also be waterproofed. "For instance, we talk a lot about the use of planters on rooftops, which are a simple and effective way to isolate the plantings from the waterproofing system and protect membranes from root growth," he says. "This is in addition to other worthwhile measures, such as installing leak detection systems beneath membranes that protect sensitive spaces below, along with regular roof maintenance." As for waterproofing products, Schoenfeld says his team puts a focus on dura- bility and longevity of the waterproofing systems, "and the systems used must be selected very carefully, because you only have one shot to get things right." The real challenge in Schoenfeld's work pertains to all these measures being fully embraced by building owners. "Unfortunately, whenever you have rapid development, shortage of skilled labour, and escalating costs there is pressure on owners to select lesser products and systems," Schoenfeld says. "So, we have our job cut out for us. We continue to advocate for quality systems installed by skilled contractors. It may cost more initially, but the outcome is tremendous cost savings over the long run." Ashley Foster, technical representative for Engineered Site Products Ltd. (ESP), is even more outspoken in the challenges facing the waterproofing sector in construction. ESP has been collaborating with design and construction teams in Western Canada since 1983, providing full support for division 7 construction detailing and design assistance. The company's primary focus is new institutional, commercial, and mixed-use projects, along with a strong commitment to tunnel work. Foster says, "Our biggest focus is quality assurance, which begins with a review of substrate preparation – because if the preparation isn't done correctly or is skimped over, the best waterproofing system in the world won't perform as intended." For the record, ESP is the master distributor in Western Canada of CETCO waterproofing products, including Voltex (sodium bentonite layered within a durable geomembrane to provide protection for below-grade concrete construction such as that of Soho, a mixed-use project that utilized Voltex DS under slab and Voltex on the walls) and Coreflex (reinforced thermoplastic membrane integrally bonded to a proprietary Active Polymer Core layer, with fully welded seams). Foster says that inadequate substrate prep "is a common failing, and voids that should be filled with foam or grout cause membranes to swell and inhibit perfor- mance. Also, virtually everything needs to be checked to guard against disruptions." Foster reports that inspections have greatly dropped off over the past five years, "Yet the warrantees we provide are contingent on the owners paying for inspections from our certified team. "I understand the resistance: proper prep, waterproofing, and inspections are expensive, and in a time when developers are trying to save costs we're typically the first service to be engineered down. But waterproofing isn't just about innovative products. We have to take a holistic approach to the issue, in all building projects." A Sundeck protection from Flexstone deck coatings. Krystol Internal Membrane hydrophilic admixture creates permanently waterproof concrete. Coreflex reinforced thermoplastic membrane.

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