Buildings are either leak-free or not, there is no in-between.
A building can’t be almost waterproof. It is either leak-free or it’s not – there is no middle ground when it comes to waterproofing, says Lance Anderson, waterproofing consultant at a.b.e. Construction Chemicals.
In his view, waterproofing is a very particular business, with the industry today being far more technical in nature than in years before, while fewer skills are available.
“As we move towards newer products, the associated requirements are higher,” he explains. “For example, with some of the polyureas that need to be applied under high pressure, you ideally need a person to be more of a mechanic than a waterproofer, because something like the speed and temperature at which the mix should be leaving the nozzle of the gun, becomes crucial. Any variation can in fact alter the characteristics that you are seeking, such as a specific degree of elasticity or robustness.”
According to Anderson, the skills requirement is prevalent and will always remain an issue. Although there are many training options available, most of the training is done in parts and very rarely seems to produce a finished article. Much of the training is also done by subcontractors themselves, which isn’t the answer.
“The industry almost teaches itself, which on the one hand can be good or, in fact, you can keep problems going forward because they are not being properly addressed,” he says.
Then and now
According to Mapei South Africa’s building line product manager, Paul Nieuwoudt, a decade ago, the waterproofing industry in South Africa was almost exclusively based on traditional bituminous technology, which is still widely used. However, there is now increasing attention paid to the safety and biodegradability of construction chemicals.
“Green, low-carbon footprint technology is in high demand, both to meet environmental specifications and because of all-round advances in performance, ease of use and application productivity,” he says.
Anderson adds that the one thing that has stayed a constant for many years, the use of bitumen, is like gold – it is always recoverable. Although the recycling of bitumen is not currently driven in the country because the cost of doing that is not balanced, it is something that is worthy of attention.
Over the last 18 months, there has been a bitumen shortage in the country, necessitating imports. And the bitumen required for a waterproofing membrane is of a much higher quality than that required for roads, the big user of the material.
Modern ways to seal the cracks
In addition to more environmentally-friendly products, mainly ones that are not solvent-based, Anderson adds that crystalline waterproofing is something that is gaining momentum in the industry, although it has been around for quite some time in various forms.
In essence it is introduced to the concrete mix to make it waterproof, with no need for further intervention. When concrete cracks, as it does, the system grows crystals in the presence of water that form within the pores of the concrete, and in fact heal and waterproofs itself.
As with the crystalline system, Anderson points out that rather than new technologies being added to the market, what tends to happen is that solutions that have been around for a while are improved. These include things such as the polyureas and the polyurethanes.
“The regeneration of liquid systems is being led by the polyurea and polyurethane technologies, where the financial entry levels for waterproofing contractors is being reduced,” says Anderson. “There are also new generation polymers and the formulating of waterproofing products that are being used to increase product performances.
“The market is slowly moving away from traditional waterproofing systems due to new technologies being introduced in the form of pre-formed quick application products and longer warranty periods for TPO and PVC membranes that offer ultraviolet (UV) stability and excellent waterproofing properties,” he states.
Nieuwoudt points out that the competitive business environment in the construction sector requires fast-track applications and flexible cementitious systems, which achieve quality results with a longer life.
“Self-adhesive systems that offer reliability with labour and time cost-savings are recent introductions to the local market,” he notes.
“The trend to sustainable development of commercial buildings also means that engineers are looking at the thermal efficiency of roof designs. This has highlighted the importance of heat-reflective waterproofing coatings with solar reflectance index (SRI) ratings.”
Safeguarding buildings against the weather
He further explains that for any waterproofing job to be successful, 90% of the attention needs to be paid to 10% of the area: the corners, the joints, the cracks and the fills between horizontal and vertical surfaces.
“While careful attention to these areas is required, the demand is for rapid easy-to-apply, effective systems that have long service intervals,” he says. “Whether waterproofing a typical flat roof, balcony or terrace, curved roof, guttering and downpipes, a total product package should offer appropriate priming, bonding to all typical construction surfaces, crack-sealing ability and a strong weather-resistant final layer.”
According to Anderson, waterproofing failures can only be attributed to four reasons: bad material, bad workmanship, bad design or damage, and the biggest culprit is the latter. Typical causes include additions to a roof, such as a television mast cable being nailed down through the waterproofing.
A lack of maintenance also causes unnecessary problems. “When a product is said to be ten-year maintenance-free, it doesn’t mean that you don’t have to clean out the outlets where the leaves have fallen,” Anderson explains. “One still has to look out for the high-risk areas such as the outlets, the up-stands where movement of the roof is normally picked up and the fit pulls away. Getting things like this fixed quickly can save time and further damage.”
Sitting on a committee that has been reviewing waterproofing regulations in South Africa for the past couple of years, Anderson advises that the South African Bureau of Standards (SABS) is currently updating its regulations and is very close to publishing an updated version.
Full thanks and acknowledgement are given to a.b.e. Construction Chemicals and Mapei for the information given to write this article.
Waterproofing innovations to look out for:
– Crystalline system.
– Polyurea and polyurethane technologies.
– New-generation polymers.
– Pre-formed quick application products.
– Fast-track applications.
– Flexible cementitious systems.
– Self-adhesive systems.
– Heat-reflective waterproofing coatings.