Teak to glass

In another thread about Island Gypsy, I spotted this:

Marin said:

The owner did a superb job of replacing the boat's failing teak decking with fiberglass.

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Provided everything under the teak is sound, how big and expensive a job would that be?

He did it himself and it is a huge job if done properly. Working several days a week it took him two and a half summers. He did a spectacular job. Even though the subdeck is a glass-ply-glass sandwich like almost all fiberglass boats of this type, the teak decking adds stiffness and this has to be replaced if the teak comes off. I's not a matter of strength but of stiffness.

He had as an advisor on the project a fellow with a sailboat on our dock who used to be the chief engineer at Uniflite. This fellow advised putting two layers of glass over the subdeck but the owner wanted to make sure the deck was good and stiff so he put four.

He took his time and did a beautiful job, better, our Uniflite friend said, than the factory probably would have done it. The deck is so strong you could probably land a plane on it.

The last half-summer was spent applying the non-skid surface and painting.

When we were looking at the finished job one day and I was asking him about the effort it took he said that had he known at the outset what a big and long job it would be he never would have done it. But it's the kind of project that once you start you pretty much have to finish. So he did and to his credit he did not compromise the quality and integrity of the work.

I have no idea what he spent on the project but he said it was a fraction of the cost to have a yard do it.

As a reference point, I can tell you that to have the teak decking replaced on the main deck of our 36' tri-cabin cruiser with new, good quality teak decking would have cost about $28,000 in the early 2000s when we were contemplating having this done. Given the rising cost of teak and labor I'm sure its a fair amount more today.

Even if a teak deck was replaced with glass by a yard at $100 an hour, I suspect the cost would be considerably less than this.

I would be tempted to glass over the teak using the techniques in Alan Vaitses "Covering wood boats with fiberglass" book. I did a recover of the canvas over the lower saloon on an old Monk cruiser with this technique maybe 25 years ago - still in excellent condition.

At the time I had a few long phone calls with the author (may no longer be alive) and innovated with stainless steel staples applied prior to wetting out.

Anyway, something to consider at a lower level of investment.

Hawgwash said:

In another thread about Island Gypsy, I spotted this:



Provided everything under the teak is sound, how big and expensive a job would that be?

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I think I remember about $15000 for the main deck, maybe half again for the flying bridge...a little less if done together.

I did mine for about $1000 in materials. Not perfect but still many compliment it....I need to go back and fix a few imperfections.


It took about a month. A week to strip the main deck, a week to strip the flying bridge, a week to glass the main and bridge, and a week to fill and paint. I did remove the seats on the flying bridge also...so fixing the flybridge fairing took some time to fill and get pretty good...call it another week but not full days.


This year going with gray Interdeck paint as the white is just too hard to keep clean...

I helped remove a teak deck, and prep. The hardest was removing the teak deck. We tried to save the teak strips but soon learned no matter how hard we tried very fee strips could be saved. So we used linoleum scrapers and ripped up the teak strips screws and all. Took two days. The fiberglass under was damaged by the scalpers. Took another couple of days to repair the fibers are glass and fill in the screw holes. We used a big floor sander to sand down and smooth out the drck. He hired a person to fiber glass and finish the deck. Took about two weeks. About 2 grand and a lot of grunt labor.

The our boat the Eagle still has teak decks. That I maintain each year. Teak decks give plenty of signs they need repairing and warning. They fail because the owner did not maintain them. About 4 to 8 hours each year. We prefer the teak decks as they are part of the Eagles charm. So evaluated the teak decks be for you decide.

According to the shipwrights and ex-yard owners on the Grand Banks forum, glassing over teak decking is a REALLY bad idea. Wood moves and expands and contracts, movement made even easier to do by the seams between the planks. Glassing on top of existing planks will ultimately fail because the movement of the wood underneath will lead to tiny cracks in the fiberglass which will then grow into bigger cracks until eventually the whole thing will have to be torn up and done properly.

These guys are not theorizing or speculating, they are speaking with the experience of having to fix decks that had had this done to them or in at least one case, tried it and some years later had it fail.

Marin said:

According to the shipwrights and ex-yard owners on the Grand Banks forum, glassing over teak decking is a REALLY bad idea. Wood moves and expands and contracts, movement made even easier to do by the seams between the planks. Glassing on top of existing planks will ultimately fail because the movement of the wood underneath will lead to tiny cracks in the fiberglass which will then grow into bigger cracks until eventually the whole thing will have to be torn up and done properly.

These guys are not theorizing or speculating, they are speaking with the experience of having to fix decks that had had this done to them or in at least one case, tried it and some years later had it fail.

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Yep, that's what "those guys" say. But the guys who've done it in Maine for 30+ years - it works for them.

My guess is that "those guys" weren't familiar with Vaitses' technique because his technique assumes movement.

Edit: this seems familiar - didn't we go through exactly this point - counterpoint a few years ago?

Maybe, I don't remember. But if you want to debate the notion of glassing over an existing teak deck you'll need to take it up with the people who've had experience with these attempts over on the GB forum. I've never had any direct experience with it so all I can do is pass on what people who have had experience with it and its deficiencies have written. I will say that their reasoning makes sense to me and their record of experience gives them a lot of credibility in my view.

Anyone contemplating the replacement of a teak deck with fiberglass would do well to research all the alternatives directly with people with actual, preferably professional, experience with the various methods and then come to their own conclusion.

I guess there are ways to glass over a teak deck...I have never heard of one that I would attempt...but again...it is entirely possible....


....just don't know why one would do it other than cost or time ( and I doubt that based on what would still need to be done to make it look right)....


....of the many projects you can shortcut.....I feel that might be one of the worst.

Moving away slightly from glassing over the teak - - the initial discussion was about removing the teak and replacing it with layers of glass. What about where you have soft spots ie the core has rotted/gone mushy with water ingress (via the screws) - the teak has to be removed, then the top layer of glass, then the foam to expose the bottom layer of glass then start from there. That's what I am looking at in a couple of areas. I have a rough idea about how to go about it - I have a source of foam but it would be really good to get some advice/pictures of this operation from a been there done that got the T shirt owner. BruceK I seem to remember that you wear the T shirt.

cheers

Brisyboy said:

Moving away slightly from glassing over the teak - - the initial discussion was about removing the teak and replacing it with layers of glass.

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Yes, that was the thrust of the question. Can't see the long term advantage of going over top of the teak. Be like painting a dirty car wouldn't it?

Glassing over teak is a real bad idea, it's not just the movement of the wood cooking and shrinking, it's the natural oil in the wood. Even then best prep of the wood and de-oiling with a astringent, the oil rises a few years later. Ergo; deep trouble again, particularly in warm climes.
Martin "shipwright"

If the construction of the subdeck is the typical glass-plywood-glass sandwich, what creates the soft spots is the rotting of the plywood core. The only real cure for that is to remove the teak planking over the soft area, cut out the bad section of subdeck and make a new section with new glass and new plywood.

I suppose one could carefully cut away the upper layer of fiberglass and the rotted plywood and leave the lower, usually much thinner layer of fiberglass intact. Then make a new plywood core, glue that into place and put new glass over the top of it to fair into the surrounding upper layer of glass. Finally, the teak is replaced on top of the area.

This is pure speculation on my part, however. I don't know of anyone who's done this so have no idea if it would work or not.

Be aware that, depending on how the boat was manufactured, pulling up the original teak deck planks very often destroys them in the process. Some of the bedding compounds used by some of the manufacturers have adhesive qualities and the planks have to be pried up with some force which very often causes them to snap.

I know of instances where individuals have pulled up a teak deck and were able to re-use the planks after the subdeck was repaired. So it will depend on the nature of the bedding compound that was used and the condition of the planks. If they are very old, have been sanded or worn thin by the use of teak cleaners/restorers and are somewhat brittle with age and weathering, they will most likely snap.

I know nothing about the repair of foam-cored decks. I have assumed, perhaps erroneously, that a foam-cored deck can't rot so will not develop soft spots. But maybe the foam can absorb water and get mushy and the end result is not unlike the rotting of a plywood-cored subdeck. Someone with experience with foam-cored decks will have to give us the right info here.

A too-do project we're looking forward to doing when we have more time in a year or so is to rework the teak "landing pad" on top of our aft cabin. This is the pad one walks on to get to the flying bridge steps.

The seams are totally shot--- I have them taped up to prevent rain water from working its way down into the aft cabin--- and the planks seem to be thinner than they ought to be, perhaps from too-vigorous sandings in the past. So I don't know yet if we'll be able to use the same planks again or if we'll have to make new ones.

I'm hoping to be able to use the same planks, but this will depend not only on their thickness but also if we can get each one of them off in one piece.

Brisyboy said:

Moving away slightly from glassing over the teak - - the initial discussion was about removing the teak and replacing it with layers of glass. What about where you have soft spots ie the core has rotted/gone mushy with water ingress (via the screws) - the teak has to be removed, then the top layer of glass, then the foam to expose the bottom layer of glass then start from there. That's what I am looking at in a couple of areas. I have a rough idea about how to go about it - I have a source of foam but it would be really good to get some advice/pictures of this operation from a been there done that got the T shirt owner. BruceK I seem to remember that you wear the T shirt.

cheers

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Hi George, are you sure it has a foam core? normally yachts do not have foam in the decks, it's to susceptible to heat.
Martin

Hawgwash said:

Yes, that was the thrust of the question. Can't see the long term advantage of going over top of the teak. Be like painting a dirty car wouldn't it?

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Well, then let me enumerate the advantages of retaining the teak:

1. you don't have to remove the teak
2. you don't have to "fix" what was below the teak
3. you don't have to raise the deck back up to the previous level or
4. you don't have to figure out what to do with all of the areas (cabin, rail, hatches, etc) that are now exposed when the teak is removed
5. you don't have to replace whatever properties (sound deadening, temperature shielding, added stiffness, whatever...) were provided by the degraded teak
6. you don't have to re-engineer every deck penetration (cleats, filler plates, again, whatever...) for a deck that is now lower / thinner

That's off the top of my head, and hey, your mileage may vary.

psneeld said:

It took about a month. A week to strip the main deck, a week to strip the flying bridge, a week to glass the main and bridge, and a week to fill and paint.

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With regards to the fellow I described with the Island Gypsy on our dock who replaced the boat's teak deck planking with fiberglass, I do not know if he had to make repairs to the subdeck due to rot in the core. If he had to do this, this could account for some to a lot of the time it took him to do the whole job.

Marin said:

If the construction of the subdeck is the typical glass-plywood-glass sandwich, what creates the soft spots is the rotting of the plywood core. The only real cure for that is to remove the teak planking over the soft area, cut out the bad section of subdeck and make a new section with new glass and new plywood.

I suppose one could carefully cut away the upper layer of fiberglass and the rotted plywood and leave the lower, usually much thinner layer of fiberglass intact. Then make a new plywood core, glue that into place and put new glass over the top of it to fair into the surrounding upper layer of glass. Finally, the teak is replaced on top of the area.

This is pure speculation on my part, however. I don't know of anyone who's done this so have no idea if it would work or not.

.........

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That's normally how it is done. Removing the lower GRP layer would generally multiply the time, cost, complexity and effort several times over.

For my foredeck I removed the fittings and the teak, getting 95% or the strips up intact. There were 960 Robertson head screws to remove, perhaps evidence of the PO re-bedding the deck as I doubt the factory would have used that type of screw. The bedding under the teak stays soft, it doesn't cure underneath where not exposed to air (on purpose) so it tends to get everywhere when you lift the strips up - a very sticky mess. I left it dry and cure in air and then scraped and sanded it off. I'm still using the teak strips for some projects. Where the PO's efforts to fix the deck failed completely was that he did not remove the wet/rotten core.

When I had all the teak off the yard then cut away the top GRP layer, in sections 3-4ft wide, to expose the rotten or wet balsa core. Thia was done to provide somewhere for us to stand/kneel while working. The lower GRP layer alone is not strong enough to support people. After the balsa core was removed the lower GRP layer was sanded and two layers of glass were laid and faired before 2 layers of 6mm marine ply were laid, with sheet joins offset. Then the upper GRP layer was re-created prior to final fairing and awlgrip with non-skid. For an area of 92 sq ft the yard's time and materials cost was $17k.

For my boat deck only part of the area was soft and repairs were limited to those areas. In this case the process was similar except that closed cell foam was used instead of ply.

Been there done that with my IG36. I had the shipwright remove all teak, it was beyond saving. 2 layers of f/glass to the unprotected bow which was then painted in non slip. Aft of that, one layer of f/glass, fresh teak, all glued except for the first strip,to retain originality.
There was a lot of filling fairing and messing about. It took 6 weeks. It is a huge job but if I had not done it the boat would have ruined.
Surprisingly we found a foam sandwich deck substrate, not a teak sandwich, and it was clearly original. The only area of teak sandwich was a square area just forward of the bow step up, and that was black soft and damp, and replaced with foam.
The biggest cost by far was relaying teak, so unless you are a traditionalist, go with a painted finish, but expect hot bare feet. It can be made to look good.

Thanks for that explanation, Brian. The process you describe makes a lot of sense and I can see how it would save a lot of work over simply cutting the entire subdeck section out leaving a hole.

The only way I would glass over teak would be to screw plywood (more dimensionally stable) over the teak and then use epoxy and glass...more expensive but probably a good idea when over bare wood.


I didn't have to re-engineer or worry about the properties that the teak added,...and I don't think most do.


There was less releveling to worry about than if the teak remained and additional buildup was made.


There was nothing to worry about around hatches or deck fills on my boat...in fact it was easy to cut off the 1/2 inch of hoses below which were eventually replaced when I did my tanks the following year.


It may depend on your boat but al the TT that I looked at if the decks needed replacing were all about the same. No big deal to rip up yhe teak and add a few layers of glass...with getting rid of the wood...you could use much more inexpensive and easier to work with polyester or vinylester resin....if not easier for some...at least faster.

I redid my aft and side decks. I didn't have teak decking, just soft decks. I cut out the top layer of glass then removed the rotted and mushy balsa core. After that I sanded the exposed glass in the lower layer and vacuum bagged down a layer of 1/2" core-cell closed cell foam except in load bearing areas. After the resin holding the core down kicked I built up the load bearing areas with solid glass (alternate layers of roving and mat) to the thickness of the core. The next step was to put down a new top layer of glass. I vacuum bagged down three layers of 1708 biaxial stitch mat with layers of mat between and a final layer of mat on top (all done in one operation). I did the job in relatively small section and the work described above took about 3 days per section. I think the vacuum bagging is essential to get the core to adhere well to the glass. When all the glass work was done I faired out the surface with epoxy based fairing compound, sanded it fair and painted with two-part urethane. Fairing took about the same time as the structural glass work in terms of days. All together the project took about two weeks. The hardest part was fairing and painting. Materials (foam core, fiberglass, epoxy, fairing compound and paint) cost about $1,100 for my job. I think the labor was about 110 hours (I did it myself). To have a yard do it would likely have run 120 hours so say $6K to $12K for labor depending on local rates. Having the yard do the work would also include haul and launch. When I did the work I did it after my Fall haul out, so there was no extra hauling charge.

The trick is to do it in reasonable bits. The first one will take you a while, but the later sections will go more quickly. Also, if you do it in sections, you can use the boat after you get the top layer of glass on each section. In other words, you can do this in the water.

This was on my glass boat, not the woody shown in the picture.

We snuck away for a few hours to see the Mission Impossible matinee...

Anyway, I think everyone's agreed that an epoxy bond to unencapsulated wood will fail (ply will work).

But mechanically fastening the two does work, though below the waterline it extends the life only a few years and isn't appropriate for the boats here. A refinement on that technique - called C-Flex- with an elastomeric separation has faired better.

Another advantage of a covering technique is that it can be tried on an area - e.g. foredeck only - without turning the entire vessel into a salvage project until completion.

Or, hell, go with the nuclear option and tear it all away.

Martin J said:

Hi George, are you sure it has a foam core? normally yachts do not have foam in the decks, it's to susceptible to heat.
Martin

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Martin,

Pretty sure its foam - I drilled a small test hole into the underside of the upper deck/flybridge and what came out on the drill bit was white (ish) and granulated

George