Epoxy Coating Teak Decks

Issues related to boat specifications or performance

Epoxy Coating Teak Decks

Postby Frode » Sat Mar 05, 2011 8:54 pm

There have been several discussions throughout this board's life regarding what to do when a teak deck becomes too old to rescue, too much bother for the owner to deal with, or just plain undesirable. There are at least three common alternatives:
  • Remove the old teak deck and replace with new (won't work for those who are just tired of the teak)
  • Remove the old teak and replace with a synthetic, look-alike form of decking (won't work for those tired of the look, or the heat, nor those who won't have anything so "plastic" on their boat - yes, I see the irony in that statement)
  • Convert the surface to a painted, non-skid surface
The last option is what I have been leaning towards for years, and that many of our other board members have also either performed or are considering performing.

The process is potentially different depending on whether you have a wooden or fiberglass boat. On the wood boats the subdeck was made with a high grade of exterior plywood, quite adept at resisting rotting from water intrusion through a leaky deck. A fiberglass boat, however, often used an inferior quality plywood in the deck core. Nothing else was needed since it was encased in resin and would never get wet - that is, until the teak deck leaked through the screw holes which penetrated into the core.

On a fiberglass boat which has had leaks for an extended period of time it is quite possible that the plywood core needs to be fully or partially replaced, or at least repaired. On a wood boat, however, chances are good the subdeck is still in decent condition and it is not necessary to remove the teak to perform repairs.

Now, we're getting to the issue I wanted to discuss: The option of glassing over (or at least epoxy coating) the teak. I have studied up on this for several years, read hundreds of discussions with thousands of posts, and have gathered lots of opinions, but hardly any experience. From the die-hard opponents there are several issues being pointed out. I'd like to bring a few of these up for discussion and see what real-life experience people have had.

Argument 1: The teak is oily and epoxy won't stick
Well, this argument I can pretty much kill myself. Not only have I primed most of the to-be-varnished teak on my boat with a few coats of epoxy I have experienced absolutely no signs of lifting anywhere (after more than six years). Obviously then, it is possible to get epoxy to stick to teak.

Argument 2: The teak planks will expand and contract and the epoxy will not stick
I have no personal experience with this, but all those who have attempted to remove teak attached with epoxy glue will testify to how extremely well attached the teak is to the epoxy.

So, not only do we have convincing evidence that epoxy will stick to teak, as well as CPES or other teak specific primers, but also that the force of the continual contraction and expansion of the individual teak planks is not enough to break the bond with the epoxy glue used to glue them down.

Argument 3: Epoxy will not stick to seam compound
Again, I have no personal experience with this, but I can imagine it to be true. I have spilled epoxy on other rubber-like compounds and have had little problem getting the epoxy to let go. I know of people who have coated a fully seamed deck, but don't know how long or how well it held up.

This problem, however, appears to have a simple work-around: Replace the seam compound with thickened epoxy. The Gougeon brothers, the people behind West System epoxy, have a lengthy article on their web site showing an entire boat being done with thickened (and blackened) epoxy as the deck seam compound. I have no information on how well this held up, but figure as long as they keep in on their site, and the process is being recommended by them, it should have a certain merit. I am, however, quite interested in hearing from anyone who has real life experience with this approach.

Argument 4+: It will ruin the charm/resale value/usability, etc.
That discussion is for a different forum - I'd like this one focused on practical issues, not individual tastes.

Arguments for (mine)
A surface of laminated planks of wood, such as the bulwarks on a wooden GB, holds epoxy very well and shows no signs of splitting in the seams due to contraction/expansion of the individual planks. Hence, assuming the bond with teak is as strong as that with mahogany, a laminated surface of teak planks, which is what the deck will become once the seams have been replaced with thickened epoxy, should hold equally well.

I have re-coated my bulwarks, and did not use glass cloth first, and the epoxy has held without cracking or lifting. Using nothing but logic (i.e. no real life experience) I would expect that coating the teak deck with epoxy would hold up just as well, without using any kind of glass cloth to help restrict and/or transfer any stresses in the wood itself.

Conclusion (barring any real evidence to the contrary)
The process should work. In fact, I am even wondering if the epoxy coating is required, for any other reason than as an all-purpose, high-build primer, used to even the surface prior to painting.

I am willing to be the first one to do this should it turn out no one has attempted this approach before. I will coat the bow area of my deck, where I expect more stresses and movements than on the side decks and see what happens - the resulting knowledge will be well worth it to me.

I may even take an area and just coat it with the standard paint system I use (Sterling primers and LPU top coat), with applied non-skid in selected areas, and see how this fares in comparison. After all, the bulwarks were previously painted without using anything but the low-tech primers available more than forty years ago, and they've held up well.

If you have opinions about this process, but they are not educated opinions, please save them for another topic. However, I would very much like to hear from all of you who have tried, and possibly failed, using an approach that is similar to my proposal, even if your scenario is not directly related to teak decks.
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Postby Barry L » Sun Mar 06, 2011 6:06 am

Frode
I am on the fence here between an educated opinion and just a thought, bear with me. I have seen a rotten wooden boat glassed over with glass and polyester resin. Probably been done thousands of times. But on this boat the process was a little different. 1st coat was a polyurethane ( I think ) sealant like Sikaflex or 5400, applied with a notched trowel, quickly followed by a heavy cloth. The cloth was stapled into the wet sealant with THOUSANDS of staples. After that the hull was built up with more glass and polyester resin, just like any glass hull. The goal was to get the strength of FRP and have it bonded to the old hull with something that will never let go even when flexing. Don't know why this would not work on a deck.
Barry and Debbie
1970 Grand Banks 36' Classic #198
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Postby Frode » Sun Mar 06, 2011 11:56 am

Barry L wrote:1st coat was a polyurethane ( I think ) sealant like Sikaflex or 5400, applied with a notched trowel, quickly followed by a heavy cloth.

Barry, I have heard of lots of interesting methods used when adding life to old, tired wooden hulls, including asphalt cement and tar paper followed by plywood and then glassing as an FRP boat. I can also see the thinking behind these approaches and follow the logic as to why they should work. What I'm missing, however, is a long term analysis to see how well this holds up.

I know I can paint the decks with exterior latex paint from Home Depot, which would also hold a non-skid product (sand, walnut shells, polypropylene beads, etc.), with no other preparation whatsoever, and I would have leak free decks that would last an easy 3-5 years (I have tested this process on areas of decking around my pool in Las Vegas, which has some of the most fierce UV exposure in the US, in addition to taking the saltwater from the pool).

What I don't know is what happens after this period, and what needs to be done then to continue having the good looks and benefits of these types of decks. I hate having to take things back to an original state before fixing. Ideally, I want a deck which would only require another coat of paint every 5 years or so - this I would consider very low maintenance.
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Postby Luke Lomeland » Sun Mar 06, 2011 5:07 pm

Frode,
To epoxy over or seal a teak deck in any fashion may be taking a chance not worth taking. Having said that epoxy holds so well, what will have to be done if there are failures in the system. The removal will/would be twice the work. Not removing the teak and sealant is only asking for trouble. A dentist doesn't repair a cavity by putting a filling on top without removing the decay. What, with possible wet plywood and fiberglass underlayment areas as well as semi porous weatherd teak with sealant residues remaining on the sides, could give countless areas for epoxy to fail a bond. Epoxy does not like to be heated past a certain temp, it begins to break down even if coated and we know how hot the foredeck can become. I believe there are too many negative variables outweighing the chance that one could get the "system" to work perfectly as designed the first time. Just my thoughts.

I did do a teak venner deck on a Norwegian pilot cutter I rebuilt years ago. Just as described in the Gougen manual. Was and is still beautiful after all these years. 1/4" quarter sawn teak strips 3" wide. Clean, new glassed subdeck. Short story - trowel thickened, graphited epoxy, waxed screws and washers between strips to hold down and allow epoxy to rise up between strips, leave overnite removing screws next morning. Stubborn screws got the hot end of a soldering iron. Fill all screw holes with more black epoxy, fill void areas between strips and sand entire deck to fair. I used cetol on the deck to allow the epoxy to last longer - the graphite helps but still doesn't like UV. Holding up well.

Regards
Luke
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Postby Frode » Mon Mar 07, 2011 1:45 pm

Luke Lomeland wrote:To epoxy over or seal a teak deck in any fashion may be taking a chance not worth taking. Having said that epoxy holds so well, what will have to be done if there are failures in the system. The removal will/would be twice the work. Not removing the teak and sealant is only asking for trouble. A dentist doesn't repair a cavity by putting a filling on top without removing the decay. What, with possible wet plywood and fiberglass underlayment areas as well as semi porous weatherd teak with sealant residues remaining on the sides, could give countless areas for epoxy to fail a bond. Epoxy does not like to be heated past a certain temp, it begins to break down even if coated and we know how hot the foredeck can become. I believe there are too many negative variables outweighing the chance that one could get the "system" to work perfectly as designed the first time. Just my thoughts.

Trying not to be rude in my reply, this is exactly the type of comment I was hoping to avoid. You are presenting arguments that are entirely based on your opinion, not on any type of experience or facts, and the issues you mention are either incorrect or invalid.

First, epoxy does not break down when heated, it simply becomes softer (it breaks down when exposed to UV, which is why it is always painted). When the temperature drops it stiffens back up. Epoxy, with glass cloth, is used on every last one of the wooden Grand Banks boats, underneath the paint, both on the flybridge deck and the boat deck. After all these years it holds up as well as you could expect anything to hold up. As such, we're not discussing the merits of epoxy resin, which we know to be excellent, but merely the application process.

Also, mentioning that decay must be removed before coating is something that goes without saying. Just as I would never paint the cabin sides, or the hull, with wet and/or rotted wood underneath, I would, of course, not attempt anything that stupid with the decks.

While I appreciate you sharing your experience with epoxy as a seam compound, the first half of your reply represents the kind of attitude that prevents new approaches from being attempted. In order to get a creative process going we need to embrace the idea that everything is possible until proven otherwise.
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Postby fogleew » Mon Mar 07, 2011 6:59 pm

Don't get discouraged Frode. There are still a bunch out here in the same (or similar) boat.

Little Red is an 86 but the decks are real thin and I'm looking at replacing or doing something else to extend the lift. Right now it will be one of two options ... 1) take the deck off and and rework with closed cell polyurethane foam (to build thickness and maintain the gutter) with about 1/4" build up Glass/Epoxy on top tied to the original glass or 2) redo the seams after cutting them down to 1/4" from the top ... and drop the screws 1/8" w/ sealant on top ... not enough room for bungs. #2 may be just a life extender ... not a solution.

Now that you are talking about it ... I'm not sure something along your proposal might be a 3rd choice. I do not think any old house paint would be able to take the movement of the decks ... but a good exterior enamel w/ some acrylic additive might. My only problem is I don't want to do this but one time for the next 10 years minimum.
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Postby Stretch Head » Tue Mar 08, 2011 10:40 am

I have tried a few things to solve my deck problems and have seen them all fail over time. I tried a coating that was rubberized and used on a few boats here. After a year i was able to wash it off with high pressure from a hose, not a motor driven sprayer.

My boat's deck was nailed down and the PO neglected the seams so the sub deck rotted in a few places. So when you walk on it the nails come up through the deck and pop the bungs. That negates new bungs. So I pulled the nails, drilled new plug holes and epoxied in new bungs. That solved those holes.

In the seam areas, I tried every brand of sealer but the one that holds is from Teak Decking Systems. With the sub deck rotted and the seams sealed with it they hold and nothing is leaking in those spots either.

I now have so many areas where the nail heads are showing that a complete removal of the deck is my only choice. This will be my summer project and if all goes well, I can use my boat this fall.
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GB42-17 Classic Cockpit Model

My personal Banned List; All Polyester resins, Silicone, Bondo and sea sick crew.
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Postby Luke Lomeland » Wed Mar 09, 2011 7:35 pm

Frode
You didn't come off as sounding rude........
I closed that paragraph with "just my thoughts". If I were to give you my "opinion" it would have been that if there were a way to succesfully seal a teak deck by covering with materials available today it would have been accomplished by now. With thousands of taiwan boats as well as quality GB's suffering this fate there has been many attempts. I have personally observed a few attempts that have ended in disastor. Please don't let any of this disuade you though, blaze the way.
Your comment epoxy doesn't degrade, it just softens suggest what I said is correct. If epoxy is utilized to hold against tension or torque and softens, lets go of the bond, then it has degraded from it original task. Repeated softening and hardening slightly reduces epoxy's effectivness each cycle by becoming more and more brittle.
I must have been mistaken, I thought GB used and still uses polyester resins in the construction phase, kudo's to them if they have been using epoxy all these years.
If getting all the info out there doesn't fit your requirements for discussion please accept my apology for attempting to help.
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Postby Bob Lowe » Wed Mar 09, 2011 8:00 pm

Now, we're getting to the issue I wanted to discuss: The option of glassing over (or at least epoxy coating) the teak. I have studied up on this for several years, read hundreds of discussions with thousands of posts, and have gathered lots of opinions, but hardly any experience. From the die-hard opponents there are several issues being pointed out. I'd like to bring a few of these up for discussion and see what real-life experience people have had.

Also, mentioning that decay must be removed before coating is something that goes without saying. Just as I would never paint the cabin sides, or the hull, with wet and/or rotted wood underneath, I would, of course, not attempt anything that stupid with the decks.

I think you have asked and answered your own question.

Having dealt with many GBs and similar boats, both wood, composite and fiberglass, I can assure you that you have wet and rotted sub-decking under your leaking teak decking.

Southern California is about the worst environment for an old woodie, especially one with teak decking. Sun-baked all day (most days) which shrinks the teak decking and opens the seams and heavy dew at night along with some heavy rains at times to leak in under the teak decking.

Sealing it in by covering it with any waterproof coating will only exacerbate the situation. That is not only opinion, it is factual and based upon my experiences.
Good luck,
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Postby Marin Faure » Wed Mar 09, 2011 9:36 pm

Frode---

a thought concerning your "will it hold up over time" question... If you've not already done so have you considered posing your question to a larger group of people? There are many other makes of boats (CHB, Island Gypsy, etc.) with a teak deck construction similar to GB's. So I wonder if you posed your question about epoxy-coating a teak deck to forums like Trawlers and Trawlering (T&T), and maybe owner sites for boats like CHB, Island Gypsy, etc. it might get you some replies from people who have tried this, successfully or otherwise, on something other than a GB.

Even a sailboat forum might be worthwhile. A few years ago a slip neighbor tried curing a leaking teak deck on his Cheoy Lee Offshore 41 sloop by covering the deck planks with epoxy. So it can be a problem to deal with, power or sail.

But it may be that the only way you'll find out if your idea will work is to simply do it and see what happens over time. If it doesn't hold up to your satisfaction you can always fall back on the proven method of removing the teak decking and replacing it with layers of fiberglass and resin and a non-skid surface.

I do have a question, however, perhaps best answered by Bob or someone who has removed or repaired a GB teak deck. You stated in your intitial post --

"...but also that the force of the continual contraction and expansion of the individual teak planks is not enough to break the bond with the epoxy glue used to glue them down."

Are you sure the teak planks on an older GB are actually epoxied down? Based on the cores I've cut to install windlass foot switches and a chain pass-through to the chain locker, the teak planks are bedded in a kind of brown "goo." It's certainly very adhesive and after all these years seemed quite hard but it wasn't a brittle-epoxy hard. It seemed to still have a bit of flex to it. So is it epoxy or were they using something else back in the early 70s?
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Postby Frode » Thu Mar 10, 2011 9:27 am

Marin Faure wrote:Are you sure the teak planks on an older GB are actually epoxied down?

I don't know about the stuff you're referring to, Marin, but was thinking more about the posts on this forum and others where people have removed teak from boats where the decking had already been replaced with one that was epoxied down.

Just near me in the Long Beach marina I'm aware of two boats replacing decks that were between 8 and 15 years old where the planks had been epoxied down. The people doing the job ended up with teak chips and had to take a grinder to the rest because of how well the planks stuck. Granted, both of these cases were FRP boats and there's a chance the planking may have been, even at brand new, of lesser thickness than what I have remaining on my boat, and this may affect the planks ability to break loose.

I received a similar advice to yours with regards to checking in with larger groups of people with teak decks to see what experience I might find, and will definitely do this. I'll report back here if anything interesting comes up, be in positive or negative experiences. However, I have gone through many such forums before, including T&T, without finding real experience.
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Postby Sleepah » Thu Mar 10, 2011 10:04 am

Frode,

I have a lot of experience building fiberglass boats of polyester resin and can report that we definately did have trouble bonding polyester to teak. Cape Dory went under in 1990 so my info is 20 years old. But today as I cruise around Florida and the Bahamas in my GB, I come across many old fashioned polyester Cape Dories that are still getting the job done.

In our day we did a lot of glass tabing of bulkheads and occaisonally used luan plywood that was veenered with teak but only on one side. We noticed that we sometimes had delaminations on the teak side but generally not on the luan side. We blamed the oil in the teak veeners. Our solution was to grind the teak veener off the perimeter of the bulkheads before we tabbed them. However, I imagine that your old teak decks are certainly less oily than the brand new teak plywood we were using.

We used to do crude pull tests to determine the relative strength of various bonds. We used an in line scale to measure the failure point. And we even formulated a special tabbing resin which had much lower parifin levels that aided secondary bonds based on these tests. I would conclude that it is more difficult to bond to teak (new oily teak) but cannot tell you whether exopies better adhesion properties solve this problem. Maybe you should do some pull tests.

And it so happens that my '73 FG GB-42 has had it's teak decks removed by a previous owner. Unfortunately I do not know how or why my decks were removed since it was done by a PO. In my case, the decks were glassed (poly/epoxy, who knows?). And the interface between the cabin sides and the decks was finished with a 3/4 x 1 " teak strip which was caulked and screwed into place. Subsequently the whole boat was awlgripped. And now the paint is bubbling and peeling from those teak strips but not the glass hull and deck; another teak adhesion issue to be sure.

I also believe that freeing the boat of the weight of the teak and the resulting deeper bulwarks are further advantages of removing the decks and discarding them. This seems to be the proven way.

I might also recommend that you attempt to determine if there is any moisture (rot) in the underlying deck. Boat surveyors have many years experience with moisture meters. And recently I purchased a home in Florida and the home inspector used an infa red camera to apparently determine that there were no leaks in the 5 skylights in my home.

(Yes, guys...I now live on the dirt after three years aboard. It was either that or a new wife!).

Frode, hopefully this helps.
Howard Means
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Postby Frode » Thu Mar 10, 2011 11:45 am

Luke Lomeland wrote:If getting all the info out there doesn't fit your requirements for discussion please accept my apology for attempting to help.

On the contrary, Luke, I very much do want to get all the information out there, but the current problem is that there are lots of ideas, thoughts, and opinions on this subject, but very little hard experience.

So, when I got on your case for presenting an entire paragraph of opinions it was because I was really hoping to keep this discussion limited to actual experiences. As you can see from my own post, I have plenty of opinions about how something might or ought to work, but in the end these are just that, opinions, and only work as a basis for further research.

I have run large teams of highly qualified software engineers, in discovery, design, and implementation phases, and I always tried to let people know that the first thing I would do when presented with an idea is to subject it to intense scrutiny and that all unsupported claims would be regarded as just another opinion until proven or disproven. Those who have read my posts on this board over the years know that I apply the same principles to many claims being presented here.

If you start with the idea that everything is possible, but nothing works well, unless proven otherwise, you get the idea of where I feel we stand on this topic. If people can state that they don't think this approach is going to work because they've heard that it won't, it either means someone is sitting on real-life experiences or lots of people are repeating the same fallacies (like the one about cholesterol causing heart attacks).
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Postby fogleew » Mon Mar 21, 2011 8:38 pm

Frode,

If Varnish sticks to teak handrails and only UV, heat and physical damage can break it down .... I see no reason to assume the decks would fair any worse. The critical considerations .... how dry should the wood be to accept the surface treatment and how long will the material last before damage causes water to intrude into the teak. If you coat with CPES first to enhance the bond .... and everything has a few weeks to dry out first ... go for it.
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Postby Frode » Mon Mar 21, 2011 9:54 pm

I have actually been looking into some elastomeric polyurethane products, made for commercial decks (including passenger and auto ferries), with an ability to stretch over 1000% and still withstand lots of pedestrian traffic (little is needed) or even vehicular traffic (hopefully, none). Can be made non-skid either by sand or their own ground rubber compound (same company makes spray-in pickup liners as well).

These systems have all the components from caulk to primer to top coat, plus the main layer in-between. All two-component mixtures with easy-to-mix ratios, but some with scarily short pot life. Once I get hold of some of the material I will try it out and see what happens.

I already have an area of the cockpit done with epoxy (I did no prep work other than sweep with a stiff brush) which is in its 5th month now and I will soon try breaking it loose from the teak and the traditional seam compound to see how it sticks (the benefit of having a boat that can be experimented with). We've had plenty of rain since I put it down so the planks have had ample opportunity to get wet and then dry as well as shrink and swell since I put it down (which the final product would never be allowed to).
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