Adding layers of fiberglass to deck

I decided against doing it but from what i've read that many sailboats have solid glass decks and they are very strong..

It costs alot to lay up 5-8 layers of fiberglass vs encapsulating a core using the sandwich method. It's also lighter but in most cases not stronger.

The hulls of many boats are solid fiberglass and I know they have stringers but many of the sides of the hull don't.

One complaint about solid fiberglass decks is that they do not insulate well and tend to sweat on the inside.

slowjoe said:

I’ve done it on decks before and it’s worked great ...it was on a cockpit deck that was removable ..about 8’ x 7’ ... added the glass underneath... worked great

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Yes, but does the original deck have a core in it? Most likely it will and the glass you added just strengthened the bottom side of the “I” beam. A lot of builders don’t lay much glass on the bottom side of the core and adding more will stiffen the deck up nicely.

(cored ) "It's also lighter but in most cases not stronger."


The thickness will determine weather the area will flex.


A 1 inch cored deck and a 1 inch solid deck will be same strength and stiffness , but the weight and insulation properties will different.

As a wood boat enthusiast, I would never add any wood to a deck without first putting 2-3 coats of Smiths Clear Penetrating Epoxy on all sides first. It is the best end grain sealer and a fantastic bonding primer for structural epoxies. It will protect the balsa if any water gets in

Petehoovey said:

As a wood boat enthusiast, I would never add any wood to a deck without first putting 2-3 coats of Smiths Clear Penetrating Epoxy on all sides first. It is the best end grain sealer and a fantastic bonding primer for structural epoxies. It will protect the balsa if any water gets in

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I think yours is a great idea. And adding to your suggestion pertaining to plywood is to avoid using anything thicker than 1/4" if there is curvature. Much easier to laminate thin plywood than to bend thick rigid sheets

Had a similar issues on our teak covered flybridge . . . Used fiberglass sandwiched coosa board, on a cleaned and dug out soft spot flybridge deck. Worked great, went back with slick coat and non-skid . . . Great improvement!

So, as mentioned earlier, she's in to get the teak off. Oddly, it appears as if the teak was an afterthought on this hull. Beneath it all is a nicely done anti-skid fiber glass sundeck...full of holes now from the deck screws. Either the teak was put on after delivery or the manufacturer molded every deck with the anti-skid and put the teak over it when ordered that way. Unfortunately with the anti-skid sections being slightly higher than the surrounding fiberglass the deck had to be faired with whatever compound it is that's left behind. I suspect the teak overlay wasn't flush on the deck in many areas. It was highly susceptible to water penetration in any spot the slats had space beneath them simply from flexing. It would have been minor movement but movement.

Luckily, despite all that, there hasn't been nearly as much water penetration as we feared. The only area that obviously needs re-coring (tap check) is under the techs feet and that's where some minor water damage can be found in the cabin below.

This is in Larry O'Rourke's shop and they did our fly bridge deck and steps a couple of years ago. The sundeck will be finished the same way as the step in the picture.

We're really looking forward to seeing her with the new deck and rub rail.

Things are moving along. Badly damaged area of core was discovered around the transom gate. Hard to say for sure if the leak was in the deck screws , around the edge or at the stanchion bolts but it was enough to destroy the core and the fiberglass layer beneath. The bad core has been cut out and is ready for a new supporting bottom layer, core and top (the top of the master cabin head liner is exposed). All of the old glue and original anti skid surface has been ground off. Hopefully done this week but this is only one of the jobs being done so I doubt it.

Do you mind sharing what the quote was for removing the teak and resurfacing your sundeck?

It was around $3500 CAD (before tax) and included replacing up to 4 square feet of core. We added several other things to the job so our bill is substantially more than that but I believe that was the deck portion.

Things are coming together. The rotten core has been replaced (the stanchion bolts re bedded) and a reinforced area has been added to accept the new table pedestal. While they were at it, we had a soft section of walkway (and a cracked scupper) repaired as well.

We would like to have had the boat back by now but I can't complain about the quality. I'll wait for good workmanship.

Looking very nice. Hope you hit the water soon.

Finally!! They had it for 7 weeks which I wasn't happy with but the job got done and we're happy with it. My only regret was not thinking of a propane locker to replace the sink that was just below the starboard hatch.

Much easier to keep clean however now I notice every little foot print.

Plan is to remove the deck wind guards this winter and fix up a few cracks, paint etc. The buggers are heavy as sin and we considered removing them in favor of canvas but decided against it.

Looks great, nice job.