Waterproofing & Concrete Curing Agents

To achieve perfect and reliable waterproofing, it is essential to have skilled applicators and high quality products.  It is also essential that the substrate that is to be waterproofed is ready and prepared correctly.  The substrate should be smooth and clean and free of previous coatings.

One good example is in the case of concrete slabs.  Curing agents or moisture evaporation retardants are coated on the surface of the slab during the curation period to help maximise the extent of the cure, leading to stronger and denser concrete.  The curing agents are designed to break down over time, and through wear.

To correctly waterproof such a slab, it is necessary to remove any remaining curing agents.  These curing agents prevent the waterproofing membrane from coming in to physical contact with the slab surface.  When the curing agents break down the waterproofing coating will lack adhesion to the substrate.  Because the issue is mechanical in nature and not about chemical compatibility, it will be the same for both solvent-borne and water-based coatings.

Although the curing agents do break down, it is sometimes not practical to wait before the waterproofing can begin.  In these cases, the curing agents can be abraded to ensure that following coats will adhere to the concrete substrate.  Sometimes the curing agents may be visible and easy to spot, other times it may be necessary to employ other detection methods.  The best practice though, is always for Builders to advise the Waterproofer if curing agents have been used so they can be on alert for any potential adhesion issues.

To determine if the curing agents have broken down an easy test can be performed on site.  Sprinkle or spray some water on the concrete surface and observe the behaviour of the water droplets.  If the water doesn’t soak in to the concrete surface but just beads on top (Figure 1.), then that is an indicator that those areas need to be abraded by mechanical means.  If the water soaks in to the concrete (Figure 2.), it indicates that there is no remaining curing agent and it is ready for waterproofing.

Wet-seal provides both the high quality membrane system and the skilled applicators.  Wet-seal Franchisee applicators understand the substrate requirements necessary to ensure a water tight outcome for your builds.

 Elisabeth Arif, MSc. BSc(Chemistry) – Wet-seal Product Manager