Using Waterproofing Resins and Coatings on Metal

Which waterproofing systems can be used on metal?

Three systems from the sea caravan waterproofing range have clear metal suitability: EpoxyWood, the Resin Fibreglass Repair Kit, and Prolux PU coating. EpoxyWood is formulated for wood but also lists metal among its usable substrates. The polyester resin kit bonds to most rigid metals, making it useful for structural patches and waterproof sealing. Prolux is a two-component polyurethane coating intended for properly prepared or primed steel.

• EpoxyWood – a low-viscosity epoxy resin for sealing and reinforcing prepared metal and wood.
• Resin Fibreglass Repair Kit – polyester resin and fibreglass mat for structural waterproof repairs on rigid surfaces.
• Prolux – a PU top coat for primed steel and other hard surfaces exposed to weather.

Preparing metal for a lasting waterproof bond

Metal must be clean, dry and free from rust, oil, wax or loose paint before any resin or coating is applied. Light abrasion with sandpaper or a wire brush creates a key that helps the product grip the surface. After sanding, wipe the area with a suitable solvent degreaser and allow it to dry completely.

Some coatings require a primer. Prolux is described for use on properly prepared or primed steel, so check the product data before coating bare metal. For epoxy and polyester resin systems, the key requirement is usually a clean, abraded surface, but always follow the specific instructions for the metal alloy you are treating.

When this matters on a sea caravan

Sea caravan metalwork often includes chassis rails, corner trims, door frames, step housings and bracket plates. These areas collect salt spray and standing moisture, so a poorly bonded coating can fail quickly. If the metal is painted or galvanised, the waterproofing layer is only as good as the surface beneath it. Abrading through oxidation and removing flaking coatings before application reduces the risk of trapped moisture and early detachment.