Epoxy Formulations for Non-Yellowing Waterproofing Sealants

What to look for in an epoxy formulation

Most clear epoxy systems use a two-part reaction. The ratio affects how forgiving the mix is and how hard the cured film becomes. Lower-viscosity formulations wet out aggregate or porous surfaces more quickly, which is useful in pebble-bound floors and thin sealing coats. A UV filter or UV-stable hardener is the main lever for reducing ambering in sun-exposed areas, but heat resistance should also be checked where dark surfaces or hot objects are involved.

• Mix ratio: 2:1 systems are common in clear casting and coating epoxies.
• Viscosity: lower viscosity helps penetration into grits and porous substrates.
• Cure depth: some clear epoxies are limited to around 15 mm per application.
• UV package: non-yellowing claims usually rely on UV absorbers or stabilisers rather than the epoxy base alone.

Epoxy binders vs clear coating resins

For decorative gravel and pebble floors, a low-viscosity epoxy binder such as Trasparente – Epoxy Binder for Coloured Pebbles and Grits is formulated to coat and stabilise aggregate while staying clear. For table tops, countertops or coatings up to 1.5 cm per layer, a casting-style clear resin may be more appropriate. The difference is less about basic chemistry and more about how the formulation is tuned for wetting, self-levelling and final film thickness.

Both types can carry UV-resistant properties, but dark or warm aggregates are particularly unforgiving for yellowing, so a binder described as non-yellowing on dark stone is often the safer choice outdoors.

When this matters: matching chemistry to exposure

If the surface is only occasionally wet and stays below roughly 70°C, an odourless clear epoxy such as Icrystal – Clear Epoxy Resin can work well indoors or in sheltered outdoor positions. For driveable surfaces, high-traffic areas or permanently damp substrates, a polyurethane coating may be more suitable. Prolux – PU coating is an example of a non-epoxy alternative designed for abrasion and UV exposure. Matching the formulation to traffic and substrate type avoids the common mistake of using a rigid epoxy film where a tougher, more flexible system is needed.