As Mark and luckylady say, the fibreglass route is the way I would also suggest, I have always used North East Composites, they used to be next to Caleys down North Shields fish quay, and are now now based in Cramlington, they are really helpful and supplied me with coloured flo-coat,(Coloured Fibreglass resin and hardener) and a grit like substance that you sprinkle upon it while its drying, you can have any colour you like, I opted for light grey, it drys like plastic but coupled with the grit feels really safe under foot even when the deck is wet and covered in fish scales.