Leaky teak on plywood deck - Repair? of Replace

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pjrennie

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Hi, I have recently been looking for a small boat to introduce the younger members of my family to sailing, and now have a 35 year old, 26 foot German Biga/Bicka. (I thought long and hard about something more sensible but she is just too pretty!) The biggest repair is the 'teak on plywood' deck which leaks and has rotted small (4 inch) areas of the plywood and caused some limited delamination. Re-caulking is not possible because the teaks thickness is now insufficient. Can anyone reccomend alternatives to complete deck replacement? Your advice greatly appreciated.
 
Welcome to the forum. Without depressing you too much you are describing what is almost certainly a deck off job. Although the leak and rot may seem localised when you lift the teak you are likely to find water has got in the ply and rotted the internal laminates.

You can cut the teak off in the worst parts and possibly dry and stabilise the ply with epoxy before you replace the teak layer, but think you will be forever chasing your tail.

If the ply is largely sound, you may get away with stripping the teak off, replacing the really bad ply and recovering with glass cloth set in epoxy. This is a common solution.
 
I agree, its a deck off job.

There is a slim chance some areas will be rescuable but I doubt it.

I'd suggest a new thicker ply deck, no teak and epoxy cloth sheath and deck paint.
 
Thank you for the welcome and your advice

I am not too disheartened as I was expecting that this may be required, so I will strip back the deck and see what awaits.

The deck is very curved and a small boat, so fitting thicker plywood (unless laminating) may be a big challenge, so the best option may be to replace damaged ply, glass over and re-teak.
 
Agree with everything except putting teak back on top!. Not only will it add weight, cost a lot, but if there is a lot of curvature you will almost certainly have to use fastenings to hold it down - so starting the cycle all over again! An alternative is to use teak veneers about 2.5 - 3mm thick which can be either glued or sikaflexed down, but they would have to be laid straight because you can't get edge set to follow the curve of the deck.

"laid" teak decks on either a GRP or ply substrate came into fashion 25 years or so. About every two or three weeks there is a post on one of the fora seeking help on what to do with the consequence of bad practice in this area. On a really high value boat the cost of doing it properly might be justified, but on smaller boats the cost is a much higher proportion of the value and never recoverable.
 
To my mind the real cause of rotten ply decks under teak is that the teak is so oily that no caulking will stick to the edges of the planks for very long, once that adhesion is gone water rests on the ply.

My boat has a new deck with epoxy glass now, was originally painted as they wanted her light for racing, however, most Huntsman 28's have teak on ply and invariably what I have described above it the problem.

Agreed fasteners contribute too.
 
I've the same problem and all the experts I've asked have recommend a new deck. Have priced both ply/teak and teak only, with the double labour cost on the ply/teak method the teak only comes out very near the same. The advantage of the teak only is if it leaks you know where it's coming from, with the ply underlay it can show up anywhere.
 
Depends on the construction. With traditional construction swept teak decks straight onto deck beams and seams filled with flexible sealer are usually OK as the whole structure can flex. However, if a ply substrate is used that stiffens the deck so it does not move. The teak overlay has to be attached to the substrate. If it is screwed this introduces a path for water to get in. If the teak is thick then the differential expansion rate of teak against ply means that the sealer/adhesive will eventually fail. If the teak is thin then wear will expose the heads of the fastenings. Similar things happen if the substrate is GRP. I looked at a "quality" 20 year old GRP boat the other week with the classic signs of a failing deck. Plugs popped out and in places only 2mm depth and damp along seams in several places where the sealer had failed and water was getting underneath. Re-decking in the same way would cost 35-40% of the asking price of the boat!

If you want to see a really extreme case of what can happen, have a look at Guapa - a regular poster on Scuttlebutt who has a website showing the failed deck on his Kallik 44.
 
26ft is with respect too small for a real teak deck.

Deck strakes less than an inch and a quarter won't work reliably, and you will do better to add the strength of a ply and glass cloth deck.

(although I do know of a Vertue with a real teak deck, but she was always immaculately maintained - and still the deck leaked...)
 
I was referring to "real teak" decks - i.e. no plywood - not "teak over ply".

But unless things have changed a lot in the Dragon class, Dragon decks don't get walked on, jumped on, have heavy objects like anchors and containers of this that and the other dragged over them.
 
I have had success with 2.6mm teak veneers on cockpit seats. Epoxied down and seams filled with either pigmented epoxy filler or Sikaflex. Also have similar on my plastic boat. Drawback is that you can only lay straight without a lot of waste and not thick enough for high wear areas like decks.
 
Browsing last night I happened upon some similar laments and found recommendations for www.COELAN.de. I am not sure about a shiny gloss deck but it did cross my mind that some gripfast nails through the loose teak into the plywood and a thorough soaking in this may provide a short term cure. The site contains several downloadable pdf Classic Boat tests on wood coatings that may be of interest.
 
A number of boats in the ADLS including mine have Coelan treated deck, great care must be used in applying the primer as shading can occure that shows through the finish coat. I had a problem with areas lifting but that was blamed on water getting between the ply/teak layer. Coelan was used to try and seal the decks and caulking that had leaked due to improper installation (no Sika tape)and differential movement. this is a stop gap repair untill i win the Lottery and can afford a new teak deck.
 
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