Teak Joints

My sundeck Teak is in very good shape, but I have a few cracks in the joints between the teak planks that need to be filled. The "grout" is a black color. Any hints or tips to fill in the planks? Type of material?

thanks

I've been told to use a good 2-part polysulfide seam sealant like Boat Life. It'll be interesting to hear what people recommend. I have plenty to do myself.

Blue Heron said:

My sundeck Teak is in very good shape, but I have a few cracks in the joints between the teak planks that need to be filled. The "grout" is a black color. Any hints or tips to fill in the planks? Type of material?

thanks

Click to expand...

Polysulfide is the standard. It is basically solid rocket fuel and applied correctly, should last for 15+ years.

You have to dig out what's bad, thoroughly clean with acetone and apply thin tape at the bottom of the groove, as you only want the caulk to stick to the sides of the seam, not the bottom. This is a critical step for maximum longevity.

Your cracks could be the result of problems with the initial installation, or a symptom of general breakdown, so be prepared to do a little more, not less renewing if necessary.

This is a pretty good summary of what to do:

http://www.zetamarinegroup.com/files/assets/caulking application sheet.pdf

Go back into the archives or google TDS deck caulking. The majority of new decks and repairs of older decks probably use TDS over other products. It's one part and other that using some acetone, no primers are required. You can buy the tubes on line.

The World's Leader in Pre-Manufactured Custom Teak Decks - Teakdecking Systems®

The people at TDS are very helpful. They offer great step-by-step instructions on how to use their products.

Having used several types of deck seam sealant on our boat over the years I can say with no reservations that TDS is the only deck sealant worth using. It is what Grand Banks, Fleming, and many manufacturers of high-end yachts use today.

Larry M said:

Go back into the archives or google TDS deck caulking. The majority of new decks and repairs of older decks probably use TDS over other products. It's one part and other that using some acetone, no primers are required. You can buy the tubes on line.

The World's Leader in Pre-Manufactured Custom Teak Decks - Teakdecking Systems®

Click to expand...

Larry, I think you will find that the TDS product (my, and your link above) is polysulfide rocket fuel, just as Boatlife is, or Thiokol or others that cure from moisture in the air, which is why they will cure underwater (more or less instantly).

TDS may well have incorporated the primer, but the MSDS isn't helpful in identifying what it is. Changing the brand name doesn't change the chemistry.

Our main deck was reseamed a couple of years after we bought it. The shipwright used Thiokol which was the "most common" seam sealant ised at that time. The seams have held up okay in most places but the material is obviously deteriorating as if you run your finger over a seam your finger comes up black.

A year or so later I did some seams on the teak planked pad on our aft cabin top. I used the same technique I was taught by the shipwright who did our main deck. The only difference was that I used TDS which I had just heard of. It was not even available retail yet --when I called TDS to learn more about their product they offered to send me a tube of thei caulk free which was all I needed to do the job. Today, some ten years later, the TDS seams are as good as the day they cured after we laid them down.

We've used the Thiokol as well as Lifecaulk which is almost worthless as a deck caulk as it deteriorates within a year in the weather. The chemistry may be the same, I don't know, but the TDS product makes everything else look like playdough in terms of longevity in the weather. Which I guess is why Grand Banks, Fleming, et al use it on their newbuilds.

Delfin said:

TDS may well have incorporated the primer, but the MSDS isn't helpful in identifying what it is. Changing the brand name doesn't change the chemistry.

Click to expand...

Carl: You could be right. I'm not a chemist. TDS says it is a "one-part silane polymer", what ever that is. All I know is, like Marin, I've tried the others and TDS is all I will use.

Larry M said:

Carl: You could be right. I'm not a chemist. TDS says it is a "one-part silane polymer", what ever that is. All I know is, like Marin, I've tried the others and TDS is all I will use.

Click to expand...

The sailboat we owned for 24 years, built in 1979, had teak decks with Thiokol used on the seams. Looked about the same when I sold it as when I bought it. That would have been a 2 part system, like Boatlife "P" or "Z", which doesn't require a primer and will last many, many years, but is a hassle to mix and only has a one hour working time. The single part Boatlife product is not the same stuff, so I am not surprised it didn't work out for you Marin. I don't know, but what I think TDS is doing is using the silane polymers to modify a single part polysulfide product, resulting in a product that has excellent adherence and durability. Whether it is better than a 2 part catalyzed polysulfide, I have no idea, but I wouldn't assume that because boat builders save time in construction using a product, that that product is superior, but sometimes. After all, if the deck lasts 15 years instead of 25 years, it's still out of warranty. Since silane polymers have only been developed in the last few years, I guess we'll find out in another 15 years or so whether they are superior to the 2 part systems.

If one believes Grand Banks they say they switched to TDS because they've found it to be a superior sealant. They use it not only for the deck seams but to glue the whole deck down-- GB stopped screwing their teak deck planks down sometime in the early 2000s if not earlier.

Marin said:

If one believes Grand Banks they say they switched to TDS because they've found it to be a superior sealant. They use it not only for the deck seams but to glue the whole deck down-- GB stopped screwing their teak deck planks down sometime in the early 2000s if not earlier.

Click to expand...

Odd they don't use the TDS epoxy product designed for gluing teak decks, favoring the product designed as a seam caulk.

They may use the epoxy. The GB factory manager at the time only told me that "We use TDS to glue the decks down, too."

Marin said:

If one believes Grand Banks they say they switched to TDS because they've found it to be a superior sealant. They use it not only for the deck seams but to glue the whole deck down-- GB stopped screwing their teak deck planks down sometime in the early 2000s if not earlier.

Click to expand...

We replaced all the teak on the house on our last boat. We cut and dry fitted all the pieces and then bedded the deck in TDS. We put concrete blocks on top of the teak for a couple of days. We then went back and caulked the seams. Not a fastener used and when we sold the boat 6 years later, other than some surface wear the decks were perfect. TDS is like black super glue that has flexibility.

We replaced all the teak on the house on our last boat. We cut and dry fitted all the pieces and then bedded the deck in TDS. We put concrete blocks on top of the teak for a couple of days. We then went back and caulked the seams. Not a fastener used and when we sold the boat 6 years later, other than some surface wear the decks were perfect. TDS is like black super glue that has flexibility.

Click to expand...

The correct way!
Sealing the grooves and expecting the screws and plugs to remain waterproof after 25 years is just avoiding the reality of what's going on under that old teak deck. If it makes you feel good...then continue on.

Larry M said:

We replaced all the teak on the house on our last boat. We cut and dry fitted all the pieces and then bedded the deck in TDS. We put concrete blocks on top of the teak for a couple of days. We then went back and caulked the seams. Not a fastener used and when we sold the boat 6 years later, other than some surface wear the decks were perfect. TDS is like black super glue that has flexibility.

Click to expand...

Cool, glad it worked well. TDS seam caulk looks like it has the same tensile strength as 3M 4000, (300 psi), but quite a bit less than the epoxy TDS sells for gluing decks (7,600 psi). Hard to beat epoxy if you want something to stay put.

Anode said:

The correct way!
Sealing the grooves and expecting the screws and plugs to remain waterproof after 25 years is just avoiding the reality of what's going on under that old teak deck. If it makes you feel good...then continue on.

Click to expand...

Actually the screws and plugs are rarely the problem behind serious moisture getting under teak deck. At least so says every shipwright I've ever talked to about the care and feeding of teak decks. The real problem is deck seams pulling away from one side of a groove or the other. This is why it's so important to prep the grooves properly before seaming and using bond-breaking tape in the bottom of the groove. It can sometimes be very difficult to see the fact that a seam has separated. But when they do it's an easy entry point for moisture, and often a lot of it, to get down under the boards. From there it can migrate down alongside the screws into the wood core of the deck.

This is why gluing a deck down is so much better than screwing it down. Moisture can still get down under the boards when the side of a seam fails which is inevitable over time. But once there the moisture can't go any farther, thus preserving the integrity of the subdeck.

Actually the screws and plugs are rarely the problem behind serious moisture getting under teak deck. At least so says every shipwright I've ever talked to about the care and feeding of teak decks.

Click to expand...

When you actually pull up a few boards and take a look. Report back!
I pulled up mine and I know what I saw.
Like I said...If it makes you feel good...continue on.

I have. Screws not an issue. Seams were.

Now maybe your deck was such a mess that water was getting down through everything. But in all the discussions about the maintenance of a teak deck on the GB owners forum the seams are always the culprit, never the deck screws themselves (other than the fact that once moisture gets under the boards it can migrate into the subdeck via the screws penetrating the subdeck. But even with missing plugs little or no moisture will get down around the screws to gather under the boards. Unless the deck is in horrible shape in which case anything can happen.

Keep drinking the cool-aid.
If screws aren't an issue ever wonder why the industry doesn't screw the decks down anymore?

Anode said:

Keep drinking the cool-aid.
If screws aren't an issue ever wonder why the industry doesn't screw the decks down anymore?

Click to expand...

Faster and cheaper???????????

Anode said:

Keep drinking the cool-aid.
If screws aren't an issue ever wonder why the industry doesn't screw the decks down anymore?

Click to expand...

Read the discussion again and it will become obvious.

The problem is NOT water migrating from the top of the boards (rain, spray, whatever) down through the boards via the screws to lie under them. The water doesn't stay on top of the deck long enough to seep down that way. The problem is water migrating down past the teak boards through the seams when the sealant pulls away from one side or the other (or both) of the groove. This can allow quite a bit of moisture/water to get down under the boards very quickly.

Once the moisture gets under the teak boards it stays there, and THIS is where the screws become a problem. Over time the moisture can start migrating down alongside the screws into the subdeck core, which is usually wood, where, over time, it can encourage dry rot to get a foothold.

BTW, this is the reason one should always wash a teak deck with salt water. If water does get under the boards and migrate down into the subdeck at least it will be salt water which does not encourage dry rot as fast as fresh water. Of course there's nothing you can do about the rain falling on your deck although I have known people who sprinkle salt on their decks periodically in the hope that rainwater migrating down past any failed seam sections will carry some salt with it.

The reason companies like Grand Banks, Fleming, etc. switched to gluing down their teak decking instead of screwing it down, according to the then-factory manager of Grand Banks who told me what I'm about to tell you, is that a) its WAY cheaper to do it this way than installing a zillion screws, and b) it totally eliminates the opportunity for moisture trapped under the boards--- which he said will eventually as the deck gets older, the planks work and expand and contract and seams start to separate---- from migrating down into the subdeck because there are no screws penetrating the subdeck for the moisture to follow.

I've been on plenty of boats, including ours, that had problematic teak decks. When the deck got wet the wetness around the seams where the sealant had pulled away remained long after the rest of the deck had dried out. This is becaue the moisture that had gone down into the groove was wicking back up to the surface as well as going on down to gather between the boards. In many cases you could step no the boards and the water would bubble back up past the failed sealant.

In fact, that's how we find out where problematic seams are so we can fix them once the wood has thoroughly dried out. Hose down the deck, see where the wood is still wet along the seams after the rest of the deck has dried out, and mark the spots with tape or take a photo.

But at the same time this was happening, there was rarely, and usually never, any remaining wetness around the screws themselves on deck even those that had missing plugs. On the rare occasions this happened, I invariably found that the problem was a loose plug or badly fitting plug that allowed moisture to get around or under the plug. But these spots dried out very quickly. Nothing like the moisture around the separated seams which could remain for hours.

Now if a teak deck is a real mess with failed seams, cracked boards, failed sealant under the boards that lets them work even more, the screws will gradually and microscopically work their holes larger and then moisture could certainly get down from the deck surface past the screws to like under the boards. But the far more prevelant problem with decks that are otherwise in good condition is the separation of seam sealant from the sides of the grooves. The screws themselves are only a problem once the moisture gets down under the deck planks where it doesn't evaporate and has time to creep down alongside the lower part of the screw into the subdeck.

So yes, the screws are a problem but not the part of the screw that's in the teak deck plank but the part of the screw that's penetrating the subdeck into the core (if the core is wood).

Now if you still don't follow this perhaps a trip to Singapore and the Grand Banks yard will help make it clear for you.

I need a job at Boeing that pays me to play on computer forums all day. Then I would be smarter than everyone else.
Marin..you are the MAN!

Marin said:

...BTW, this is the reason one should always wash a teak deck with salt water. If water does get under the boards and migrate down into the subdeck at least it will be salt water which does not encourage dry rot as fast as fresh water...

Click to expand...

The reason salt water has been used on teak decks is:

• Salt water reduces mould, mildew and algae growth.
• Salt being hygroscopic absorbs moisture form the air and helps keep the wood from drying out.
• Salt water and the UV from the sun act as natural bleaching agents.

If you have leaking seams, fix them. Getting salt water into the core can not help if you have to facilitate repairs later. Our goal is to keep saltwater off the boat.

An easy way to check if have bad seams is watch when the decks are drying, when a seam stays wet longer, take a closer inspection. Chances are the caulk has pulled away from the seam and needs repair.

Boat is currently in Puget Sound. I've just removed 60 sq ft of teak deck, had the top 'glass cut out and the balsa core (mostly wet, some quite rotten) replaced. When removing the teak it was pretty clear to me that the seams let water get under the deck, and the screws then let the water into the core. There were about 950 screws. Basically all the plugs were intact and sealed.

I'm pretty certain that at some point a PO had tried to fix the deck by removing the teak, rebedding it (in some king of sticky black goop) and re fastening using square drive screws. The balsa could have largely been ruined by then, but seams starting leaking again.....

A boat yard quoted me $130 sq ft for new teak decking, but I'm just going to glass it and paint non-slip over it. I really like teak, but it gets too hot to walk on anyway if you are in the tropics. I still have some, but it is partly shaded and I haven't noticed any soft spots in it.

I salvaged most of the old deck, but if I ever use it I will use the TDS epoxy fitting method and avoid screws. Then I just have to epoxy plugs into all the old screw holes. It will get very tedious .....

Anode said:

I need a job at Boeing that pays me to play on computer forums all day. Then I would be smarter than everyone else.
Marin..you are the MAN!

Click to expand...

I do all this forum silliness from my iPad, usually while I'm in transit to somewhere. Right now it's Beijing. It's like reading a newspaper when one has a few spare moments. As I said, mindless entertainment that provides a short break while doing something real.

If you don't understand how this whole teak deck thing works then you might want to talk to the Grand Banks folks at their yards in Singapore and Malaysia. That's how I learned it. I'm just passing on what I've learned from them as well as local shipwrights who have a lot of experience with teak decks plus our own fourteen years of experience rejuvinating and maintainining a now-forty year old teak deck.

If you think GB and the shipwrights are wrong, that's fine. Me, I'm going to go with the boat manufacturer who's been putting teak decks on their boats since 1966 rather than what some amateur backyard boat fixer-upper guy happens to believe.

6221 mindless posts from your iPad while traveling do something real is very impression. I think everyone here will agree.
You are also correct about being an amateur backyard boat fixer-upper guy. My amateur status comes from not paying myself to work on my boat which is in my backyard. Something I always wanted to do when I retired and glad I had the where with all to make it a reality.
I'm the kind of guy that actually does things rather than just repeat what I hear.
Since retirement I've split much of my time between the amateur backyard boat work and boat deliveries. Real boats in real oceans going real places.
If you ever decide to take the blue doilies off your bright work and go some place real with that GB rather than the three hour tour to the private island where you own property (impresses me). Let me know. I'll send you my professional and marine resume and maybe we can cut a deal.
I've provided a couple of links for you to review when you into doing mindless things while traveling to your real job.
Maybe you'll find something here to cut and paste for the experts over on the GB Forum.
Four Options to Consider if You Think Your Teak Deck is Leaking | Teak Marine
Teak Deck Company: Maintenance & Repair

Headed back up the driveway.

Anode said:

If you ever decide to take the blue doilies off your bright work and go some place real with that GB rather than the three hour tour to the private island where you own property (impresses me). Let me know. I'll send you my professional and marine resume and maybe we can cut a deal.
.

Click to expand...

That's funny. :lol: But I would more inclined to let my dog take our boat out. Who considering his intelligence and agility would probably do a really good job. I'm reminded of the fellow at work who just got his private license in a Cessa 152 and was giving flying "advice" one day to my friend who happens to be the chief production pilot for the 787 program.

Oh well, we all have our little delusions.

The experts on the GB forum don't need any help from me or you. I dare say they've forgotten more about boats, teak decks, and maintaining them than you and I put together will ever know. And knowing how to drive other people's boats around for them has no bearing whatsoever on how much one knows about maintaining them. Being a chauffeur is easy (see my comment about my dog). Fixing the limo is a whole different deal.

PS-- I read both your links. The first one is overly simplistic and doesn't even address the issue of seam sealant separation and repair.. The second one is a little better in this regard but again doesn't provide enough detail to do much with. So I'm gonna stick with what I've learned at GB in Singapore and Malaysia and from people like shipwright and former yard owner Bob Lowe on the GB forum.

Keep drinking the cool-aid!

It's great stuff. You should try it. Particularly the flavor they call Knowledge. It's really hard to find-- try Costco--but it's worth the effort.

PS. BTW I saw a little boat exactly like yours in a yard out on the Lummi Indian reservation near Bellingham a few weeks ago. It doesn't look anywhere near as nice as yours in your avatar but it is up on blocks. :lol: