GRP and aluminium bodywork on boats and caravans

Not every restoration project is made of steel. GRP, aluminium and timber-clad bodies need a different approach to repair and finish.

GRP repair. Grind back cracked or blistered laminate to sound material. Build up new layers with the correct resin and glass cloth, feathering the edges. Gelcoat or paint to match, and never skimp on the preparation.

Osmosis blisters. Blisters on a GRP hull below the waterline are common on older boats. Open them, dry them out, treat with osmosis solution and re-barrier coat before antifouling. It is slow but necessary.

Aluminium panels. Aluminium dents and creases need specialist tools or panel replacement. Welding aluminium requires the right equipment and skill. Always use etch primer and compatible paints.

Timber cladding. Many older caravans and marine craft have timber-framed panels. Replace rotten framing, bond new plywood and reseal every joint. Do not trap water behind new panels.

Paint and finish. Use paints designed for the substrate. Marine and caravan paints need flexibility, UV resistance and good adhesion. A thin, well-prepared finish beats a thick one that will peel.