When it comes to external waterproofing in Australia, a large percentage of pedestrian and vehicular trafficable coating systems are based on modified polyurethane waterproof coating systems. These coating systems can be based on one component polyurethanes, (one component, cured by exposure to atmospheric moisture), or they may be derived from two component polyurethane coatings, which require an added catalyst to initiate the curing process (two components, cured by a chemical reaction).
But what happens over time when the coating is placed in a high-traffic area, exposed to wear and tear over time? This can include a podium area with large volumes of pedestrian traffic, roofs which have regular maintenance foot traffic passing over the membrane, and so on. In these cases, the coating systems are subject to external environmental stresses such as wind, rain and thermal changes as well as foot or vehicular traffic.
Coating systems will naturally degrade over time with exposure to external elements. Typically this occurs in the form of localised loss of gloss at areas where the coating is most exposed to the elements. In high traffic zones you might see a degradation of the topcoat, eventually exposing the underlying membrane. With pedestrian traffic, this tends to be gradual and is noticeable due to the visible degradation of the topcoat in patches (patches will appear at high traffic zones such as entries, exits or dedicated walking lanes). Loss of non-slip aggregates also occurs here. For continued safe passage for users, non-slip resurfacing should be undertaken as soon as the issue becomes apparent.
With car park situations, the loss of topcoat and aggregate will also be most noticeable at high traffic areas (entries and exits, driving lanes, and turning zones). It’s important to keep in mind that this is not a failure of the coating system to perform, but rather, an expected result of long-term exposure and wear.
The good news is that because we can reasonably anticipate this kind of wear and tear over time, we can combat it by periodically resurfacing the topcoat to maintain its protective qualities. This will help keep the body of the waterproof membrane intact, which is the part of the system that performs the waterproofing function.
This type of wear can be accommodated with periodic re-application of the non-slip topcoat from time to time. Topcoats should be inspected on a regular 6 to 12 month cycle, depending on the use of the area.
Proactive maintenance planning is imperative. If your facility has this type of waterproof coating system protecting yours or your client’s asset, it’s important to budget for continued long-term protection to maintain a safe facility.
Waterproofing maintenance of these types of coatings are on a long-term cycle and cannot be accurately predicted, as they will depend on patterns of use and foot traffic density - however, it’s generally unlikely that any localised repair work would be required during the first two to three years of service.
More highly trafficked areas may require a maintenance recoat sooner, depending on just how much traffic there is - and this may not be fully understood until the facility has been in operation for a period of time. Existing structures may be more easily predicted based on past experience.
Cleaning is an important part of maintenance, and can help slow down the degradation of the topcoat. Coating systems may be cleaned at any time by low pressure washing with a weak (0.1%) solution of neutral detergent. Cleaning annually is recommended to remove built up contamination, and to give you a chance to spot coating issues before they become a serious problem.
Cleaning should be carried out without harsh or heavy scrubbing of the surface of the topcoat, as this could inadvertently damage the coating. If using a water blaster, ensure the pressure is just high enough to rinse the surface of the topcoat. General dirt should rinse off easily, but if not, you may want to use a neutral detergent spray-on solution to loosen any stubborn contamination. Oil deposits may require a more aggressive detergent, but this should be done with care and ideally with a trial first to ensure no adverse effects damage the coating.
Want to enquire about our waterproofing consultancy services? If you have any questions or would like to explore our assistance with reviewing and programming of ongoing maintenance of your waterproof coatings, get in touch.