You have to cut out the rot
, and replace it with foam such as Klegecell or Airex, with any spaces filled with polyurethane
after the initial cure.
I bought one of those twin-blade circular saws with contra-rotating blades. TaTake a piece of coloured chalk in paw and hammer in other, and locate any SOUND deck surrounding the wet spots and mark the boundaries. Now remove the top layer of fibreglass and expose the core, and scrape out the rotten stuff. Take it RIGHT BACK (no italics) to sound wood
Use epoxy resin and some glue powder to bed
in your Airex core replacement, squish it down then put some heavy plywood
on it and a good set of even weighting to hold it in place. I use second-hand weightlifting rings, they are not too heavy and lie flat. ONce that has set, you then use HEAVY buiklders' foam to fill any crevices. That goes off in a few hours and can be trimmed with a knife. You then taper back the deck fibreglass and lay a new glass deck over then foam, using EPOXY or Vinylester resin, and when you have it almost exact, put peel-ply on the top and roll it some more.
Then rip off the peel ply when cured, make sure any edges are trimmed and sanded, and one can then use a UV resistant paint
such as Poly-U 400 which requires an epoxy primer. Then apply the Poly-U 400, and after fully cured whatever anti-skid deck paint
one would normally choose. Some outdoors masonry paints are identical formulas to Marine
deck paint, but at a fraction of the price