grp

G.R.P. (glass reinforced polyester) is also known as fiberglass. Technically, it is a plastic composite, either molded or formed in situ. The gel coat on the surface chalks and erodes to become porous, allowing water to penetrate the other layers. Repairs may be made with a urethane caulk such as PSI 901 and a basecoat of either Polaroof RAC, moisture-cure urethane, or Polaroof NW, ethylene elastomer coating, to seal the gel coat. A finish coat of either Polaroof RAC metallic polyurethane, or Polaroof NW elastomeric coating in any color, may be applied to protect the surface.