Teak Deck Care & Repair -- Bill Adams, Free State Yachts
The secret of teak decks and their proper care often is requested. Free State Yachts (FSY) even holds classes at
the Chesapeake Rendezvous now to explain proper care and maintenance to owners.
With light to moderate carpentry skills owners can do teak deck repairs, a full deck replacement is another story.
Some general comments first:
- Our focus is on Hallberg-Rassy yachts.
- One should never use or own any kind of deck scrub brush or pressure washer to maintain any teak deck...
you will quickly reduce the useful life of your deck.
- The art of teak deck seam sealing is now pretty well defined and refined. We use Teak Decking Systems™
seam compound. It's also used by builders. Teak Decking Systems™ is based in Sarasota, FL. (http://www.
teakdecking.com/). I'd highly recommend them as a technical source as well as being able to supply you with
an excellent seam sealant.
Please bear in mind this is FSY experience in working on HR decks for the last 20 years. There are many, many
species of teak, all of which have different characteristics and resulting wear characteristics. The purveyor of teak to
HR is a personal friend in Sweden and he has told me that without question, HR has and will only buy the very best
of quality teak.
In the teak deck planking configuration of the mid-80's Hallberg-Rassy's (and '90's) each plank simply has a small
rabbet on one edge and at one end which provides the gauge for the installation to the adjoining plank. When the
decks are first laid, each "blank" piece of decking has previously been milled from 12mm Burmese teak to width and
also milled with a rabbet on one side and one end. Each piece is then individually cut and "dry-fitted" to the
neighboring piece with the end butt joints staggered to the neighboring piece. Pilot holes for the screws and also a
counter bore to receive the teak plug are then drilled at spaced intervals. The plank is then lifted from the "dry
fitting", all debris and moisture is vacuumed up, and an approximately 10mm wide bead of adhesive/sealant caulk is
applied directly over the line of screw holes that have been drilled into the deck from the pilot hole - counter bore
operation. Then the teak plank is permanently installed in the caulk bead with the screws driven home with each
plank tightly butted up against its’ neighboring plank. After all pieces of teak planking have been milled, cut, fitted,
and installed with screws in the adhesive/sealant caulk bedding material (Boatlife LifeCaulk™ adhesive/sealant,
SikaFlex™, or similar products work well on repairs), the completed new deck will then have a black rubberized seam
sealant spread well and deeply with a squeegee into all the seams and allowed to dry. After thorough drying, it is
then lightly surface sanded producing a new smooth seamless deck. Note, this description was for a new deck
installation. Moving on to existing decks that may need attention...
Remember, never use a deck scrub brush or pressure washer! We've rarely seen an HR teak deck that cannot be
successfully repaired and we've seen a few that have unfortunately been pressure washed, or heavily sanded to the
point where the decks have been compromised dramatically and reduced their useful life. Sometimes, an unknowing
owner will also own a stiff deck scrub brush, wood acid, various brighteners, etc. With continued scrubbing these will
remove most of the soft grain (pith) of the teak wood thereby dramatically reducing the life of the deck. The only
deck cleaning tools you need to own for cleaning are a mop and perhaps a 3M™ blue "Scrubbie™" for tough stains.
We use the new mops with the chamois type absorbent strips and have found them to work best.
Depending on the deck's overall condition, perhaps just a light sanding to reduce the exposure of the grain of the
teak as well as the seam “rubber” or teak plugs that are "standing proud" will restore the deck to acceptable
condition. Unless deck fittings are first removed, the work will produce disappointing results with unsightly "lands"
where deck fittings exist. A worn deck needs to be analyzed carefully as to exactly what must be done. With irregular
traffic wear, some areas of the deck will be more worn than others. Wet spots remaining on a teak deck after a rain
when the rest of the deck has long since dried are telltale signs that water is present under those sections of
planking. The water is trapped on top of the fiberglass beneath the teak decking and won’t dry. In order to remove
this water to prevent possible intrusion below, the deck seams must be opened up by removing the caulking from
these planked areas. Chances are that if the boat has been cruised, sea water is trapped under the teak planking
between the plank and the fiberglass decking. If a fastener has come loose and the adhesive/caulk seal has been
compromised, then a leak can occur. It may drain into the interior or it may not, depending if the moisture finds a full
deck penetration that's been compromised such as a scupper or deck light.
In the 1980s series of HRs, a cross section of the deck from top to bottom would be: a) 12mm Burmese teak plank,
b) caulk/sealant, c) 3/16" or so of fiberglass decking, d) then a honeycomb type coring material that resembles an
egg crate that has been impregnated with resin (a little over 1" thick) and then e) another layer of fiberglass and
finally f) the fissured vinyl cabin headliner. The deck coring isn't usually compromised by a water leak, however, it
does present a problem if water enters the coring since it could run as far as half the length of the boat before it
finds a penetration to either leak down into the interior of the boat or we’ve experienced them gushing upwards as a
small geyser aft while underway on a deck that has some deteriorated caulking in the deck seams. We saw this in an
ill kept deck on a '84 HR-42 that had been cruised for 12 years with a lot of deck scrubbing and little or no care.
Regular but simple care of the deck is important. The care is usually minimal as long as it doesn't get ahead of the
owner. I can take care of a HR-42 deck with no more than two hours a week of hosing off and general
maintenance… less time than proper care of fiberglass decks with non-skid! If a plug pops out - replace it
immediately with spares on board. Check the screw under the plug and make sure it's tight - if not, back it out and
reset it with sealant on it's tip. In the following, I point out various abnormal conditions that may exist on an HR, or
any other teak deck and the way that we "fix" them.
- Vacuum bagged teak decks can develop another set of problems and unless a professional is involved, an
owner will not be able to repair his own deck. For this reason, H-R currently installs only the cockpit seat teak
overlays with the vacuum bagging process… no deck areas. However, they have offered “blind screwing of
thicker teak decks on only the largest models to eliminate the look of the teak deck plugs.
- If the teak bungs have popped out and the screws are close to the surface (<3/16"), then the screw should be
removed, counter bore the plug holes deeper, and re-fasten with the next screw size up if possible to avoid
using a larger plug. Another rule of thumb is that if the depth of the existing counterbore after the screw’s
removed isn’t at least 2/3 the diameter of the bung, the counterbore needs to be deeper.. otherwise, the new
bung has a chance to “flip out”. One should also dip the screw tip in LifeCaulk™ sealant or something similar
prior to driving it home to reseal the fiberglass deck penetration. Then install another plug (it’s not necessary
to align grain of the plug as the plug will stay in better if askew). Dip just the bottom of the new teak plug into a
varnish or perhaps just a small dot of epoxy resin which will prevent it from popping back out.
- If you suspect water is trapped under the teak deck planking that remains wet a day or so after a rain, isolate
and mark the area (3M blue tape works as long as you don’t leave it on for more than a week) and tape off a
slightly oversized area of the suspect wet deck area. It’s important you only attempt repairs to a section of
deck that you can open up and complete this process the same day. Reef out the old caulk as described
below at the lowest section of the deck that is affected, tape fast a piece of a heavy plastic sheet to the dry
teak deck outside of the isolated area, then cut a hole in the plastic sheet and tape the hose of a wet/dry
vacuum cleaner to this area. Make sure the vacuum is empty then turn it on and let it work for about four
hours. Afterwards, check the inside of the vacuum to see how much water you've picked up. Empty the
vacuum and repeat the process - continue until you do not see any more water being evacuated in a four
hour period. Remember, you will be sucking water from under the entire teak deck area, not just the area you
have isolated. Just to give you an idea, the HR42 that had the ill-kept deck had to have a wet vac run for 3-4
days before we could start the repair process. Also, remember the water could be pocketed at the lowest
point on the deck and if possible, you may want to first attack it at that point. Once you’re confident the wet
vac is not picking up any more water, cover and tape off with the area with sheet plastic that you have
completed the water evacuation to prevent new moisture from intruding and also open it up those days when
it's sunny to thoroughly dry. If the condition is very bad, such as on the HR42 mentioned, it could be days
before you’re able to really get into the repair. Once the area is absolutely dry, then begin to repair the
planking and reseal as described next. Often the areas that are most likely affected are around the deck
scuppers and other possible penetrations such as the flush prism lights that were an option years ago. Take
your time and after you’re certain the area is absolutely dry, you may have to use some epoxy resin as a
“peanut butter” mix of epoxy and microballoons to repair or plug a potential leak around the scupper or the
deck prism so that the teak decking will bed and seal properly.
- If you need to replace a teak plank or two, first you need to remove the bungs and screws. With a razor knife,
cut the caulk loose and then see if the plank will lift. If it will not lift, you will need to drill a series of holes down
the middle of the plank to open up a section where you can pull/chisel out the plank. Clean the area
thoroughly and refit with a new piece of selected teak planking, repeating the installation process already
described. It would be nice to use Burmese teak as HR does, but for a few planks a very close-grained piece
of nicely milled teak will do.
- If the caulk has become dry, non-pliable, or cracked, then it needs to be removed (reefed out) from the wood
seam and new caulk installed. Some think this process is quite tedious, difficult, and non-rewarding. Frankly, I
find it to be interesting and extremely rewarding… when completed… it moves rather quickly and is fun if you
enjoy working with your hands.
- If the rubber caulk is standing "proud" where you can scuff out a strip of caulking from the seam with a
sideways motion of your deck shoe, then it's tenacity has broken down from the UV rays and the bond to the
teak plank has released.
- If the rubber caulk is just standing proud and stays tight without rolling out by scuffing it lightly sideways, then
you can use a window glass scraper with single edge razor blades and carefully cut the rubber down to just
above flush with the teak deck. Afterwards. it’ll first appear a bit crude and raggedy, but foot traffic will wear it
down to the same height as the teak deck.
Some older decks where the teak has become well seasoned or dry and has been exposed to constant hot harsh
sun will have the caulking standing proud. This is not uncommon. A proper assessment of the condition of any teak
deck should be to determine if there is any "life" in the seam caulking or if it's "dead" and cracked, cracked planks,
“rogue” grained planks, etc.. It's likely that a 20 year old deck will have dead caulking. This is not the end of the
world and the deck may not necessarily need replacement, think of it as a chance to give yourself a beautiful "new"
looking deck by replacing the caulk and lightly sanding afterwards.. while doing a rather small area at a time.
The process for seam repair is as follows.
- Shape by grinding a flat screw driver blade (good quality steel) to a size and shape that when inserted into
the deck joint is the same width as the joint. Then grind about 5/16" up from behind the edge of the blade
(towards the handle) a rather heavy “V” notch on each side of the screwdriver blade…. Finish the tool by
sharpening the 5/16" straight edges and the straight end as well. This tool will be used to "reef" out the deck
joint and works well due to the flat edges first cutting the sealant bond to the teak and the notched area allows
room for the dead caulk to peel out… One uses a vertical two handed drag-back motion with this tool.
Professionals have routers fitted with guides that do this job faster… not necessarily any better.
- First, use a razor knife to cut between the dead rubber and the teak plank to facilitate the removal of the dead
caulk with your reefing tool.
- Make a final drag with your reefing tool to clean the teak joint and remove any trace of dead caulking.
- Then prep the joint by inserting an acetone wetted rag into the seam with a screwdriver blade and drag the
seam dry. Acetone will remove the fresh surfaced teak oil and assures a bond of the new seam sealant. Do
not attempt this indoors and use rubber gloves while remembering acetone is extremely volatile with a low
- Then take "blue" 3/4" masking tape and tape off either side of the prepped seam being careful to mask off
adjoining areas with newspaper or the like. Apply fresh seam caulking with a standard caulking gun (we use
Teak Decking Systems caulk) and aggressively tool it into the seam by pushing it down tightly with a putty
knife without allowing air bubbles to occur (not usually a problem). Sometimes the new caulk material will
shrink very slightly… it’s best to fill the seam completely and sand/cut the excess off flush if necessary.
- Pull the masking tape just before the caulking "skins" over from drying (it doesn't take long). Lightly sand the
decks and fresh caulking only as necessary. Traffic on the deck can eventually smooth any irregularities out.
Sand lightly if needed to hurry up the process being careful not to remove precious teak… No worries… the
bright new teak that’s exposed will silver out and match the rest of the deck in a month or two. Just keep the
decks hosed off once a week as usual.
A repair sequence...
1) Remove damaged planks being careful not to disturb
areas close to the edge of any adjoining plank where there
may be a joint.
2) Clean exposed glass subsurface completely including
removal of as much old adhesive as possible.
3) Close-up of shot #2...note planks adjoining the old
removed planks have a rabbet (right side). Left side also
has a rabbet underneath (not visible in photo).
4) Cut, machine, and dry fit new planks with screw holes
counterbored. Prior to fastening, lay a 3/8" wide bead of
adhesive/sealant (Lifecaulk is OK) in a line where screws
will penetrate fiberglass substrate. Now, install new planks
with screws (shown installed).
To understand proper teak deck maintenance first, throw away your teak acid, brighteners, teak oil, and yes, the
deck brush,… If you own one, sell the pressure washer to your land locked neighbor. The proper maintenance
includes simply splashing buckets of clean sea water or fresh water on your teak deck at least once a week. If you
want to “clean” it once a month, you can swab with a light mixture of water and dish detergent if you like and do a
heavy full rinse.
If you can give it (and the entire boat) a fresh water bath once a week, that's great too, however, the sea water
does make the deck turn a beautiful silver grey a little faster and the fresh teak planks (if you had to install some)
will start to seal off naturally a little quicker due the the salt drying.
Silvered teak is actually the natural process of the teak seasoning out and yet the protective natural oils of the teak
are still trapped below the surface within the teak grain.
If after a long period, your deck has black spots or is mottled in appearance, this is mildew which should be stopped.
This is the most “aggressive” cleaning process that you should attempt or have to do… It's easy… simply prepare a
solution in a bucket (fresh preferred or sea water if necessary) of 2/3rds cup of bleach, 3-4 tablespoons of tri-
sodium phosphate (available at any paint/hardware store) and a dash of dish detergent (some people say Tide™
granules work best.. others like to use granular dishwasher detergent). Swab the solution heavily (Do not scrub with
the brush that you were supposed to throw away!) with a mop and let it set for about 10 minutes or so and then
rinse with either fresh or sea water. We usually do this kind of work on an overcast or light misting rainy day… it
seems to allow the solution to work better. If you have a stubborn grease soaked area, you can use the flat 3M blue
Scurbbie on the affected area… CAUTION: This solution will strip any wax off of fiberglass surfaces, can streak the
HR blue coaming stripe and hull striping, and perhaps attack the Lexan hatches! To prevent the streaking simply
wet these areas down heavily prior to using the deck cleaning solution or better yet if you’re at dockside, allow a
stream of water to run constantly over these areas to flood away the excess solution. Personally, I don't like to have
seawater slopped around on the deck. If you're fortunate to have a water maker or plenty of fresh water tankage…
then always hose off your deck, fittings, glass, aluminum, winches, spars, sails, etc. with fresh water in lieu of sea
water. Forget the silvering process… it will eventually happen from the sun.. just takes a little longer as long as you
keep the decks hosed off.
If you find a spot somewhere has been caused by an oil (sun tan lotion, winch grease, etc.) then use a 50/50 mix of
bleach and water and blot it with a sponge, let sit for 15-20 minutes and it will come up. This is particularly useful in
the cockpit area where suntan lotion, mayonnaise, and the like have been used. If you don't have a deck wash down
pump, install one. You'll be glad you did, it makes things so much easier! Also, never apply any kind of sealant or
teak oil to teak decks! This is absolutely unnecessary work and expense, can attack the seam caulk, and oiling the
deck will definitely cause airborne dirt to stick to the gummy residual of teak oil which will turn black with grime. All
that is needed to clean the deck on a weekly basis is to hose it off… If it makes you feel better, use a little liquid dish
washing detergent, a mop, and a good water rinse. Just a little bit of bleach (2-3 capfuls) in with the dish detergent
will kill fungi trying to grow in the teak if you’re cruising in warm climes.
Again, consider a 50-lpm washdown pump that will serve the entire deck area… you can plumb it to either fresh or
seawater or both… And, yes once again, please throw away your deck brush if you have one and treat yourself to
one of the newer absorbent mops!
So, the next time someone tells you that teak decks are a pain to take care of, ask them to try to slip on one when
the deck is awash in a seaway! They are still the safest deck under foot and have been, and still are, used on
sailing ships, warships, and yachts that have long range capability such as your H-R.
Free State Yachts
Annapolis, MD USA