Period Correct Teak for a Classic Restoration, and What Cannot Be Matched

What Period Correct Teak Actually Means

Period correct teak is a specification with five parts, and the species name is only the first of them. A surveyor, an owner or a restoration committee asking for period correct material is asking about species, cut, growth rate, dimension and origin. Teak, Tectona grandis, settles the first part. The other four are where orders go sideways.

Cut is the second part. A traditional laid deck is quartersawn so the wear surface presents edge grain, with the annual rings standing close to perpendicular to the face. Quartersawn and rift stock moves less across its width than plainsawn, which is why the original builders specified it and why a flatsawn replacement plank will cup and telegraph through a season of sun and rain. The same logic governs a caprail that has to stay true over a long unsupported run.

Growth rate is the part no purchase order can command. Dimension is the part that gets discovered late, normally when someone measures an original plank and finds it wider or longer than anything currently milled. Origin is the paperwork, and on an imported species it travels with the boards.

J. Gibson McIlvain has been buying, milling and selling hardwood since 1798, seventh generation and family run, which matters on a restoration that runs in phases across several seasons rather than in one purchase. A job that pulls material in 2026 and again in 2028 wants the first lot, the cut and the thickness still on record when the second pull happens.

Old Growth and Plantation Teak Are Different Material

The teak milled for a 1930s yacht and the teak available on the market now came off trees that lived very different lives. Both are Tectona grandis. That is where the similarity stops being useful to a buyer holding a cutting list.

Old growth logs grew slowly in natural forest. Close annual rings, a high proportion of heartwood to sapwood, straight grain running long distances without wander, and color that reads evenly across a wide board. Those logs produced the long clear quartersawn stock that made laid decks possible in widths and lengths that look generous today.

Plantation material grew fast on managed rotations. Wider rings, a larger share of sapwood in each log, more color variation board to board, and grain that wanders more than a buyer expects from the species name. None of that makes plantation teak bad stock. It makes it different stock, and it changes which parts of the boat it belongs in. The Wood Database entry for teak covers the species properties behind those differences.

Supply explains most of the shift. Old growth teak from traditional sources has tightened hard, and much of what moves through the trade now is plantation grown. A restoration that assumed otherwise will have to decide between waiting on a narrow market, accepting plantation stock in the parts that can carry it, or specifying a different species where teak was never load bearing in the first place.

What Cannot Be Matched on an Original Deck

Four things on an original teak deck cannot be purchased at any grade, and a restoration goes better when the owner plans around them instead of chasing them. Getting this on the table early saves a second order and a hard conversation at the dock.

Patina is the first. The silver grey on a 60 year old deck is the product of decades of ultraviolet exposure, salt, foot traffic and whatever the crew scrubbed it with. New teak arrives honey brown with a visible oil sheen, then weathers on its own schedule. A patch set into an old deck reads as a patch, and it keeps reading as a patch until it has lived outside long enough to catch up.

Ring density is the second. The slow growth that put 30 or more rings across a narrow board is not available in plantation stock, and no kiln schedule, grade specification or surface treatment produces it. Original width and length is the third. A pre-war build may carry planks that are wider and longer than the clear quartersawn stock being milled today, which pushes a deck toward more planks, more seams and a different visual rhythm than the one the boat was launched with.

Freedom from sapwood and knots over very long runs is the fourth. Yield falls off fast when the required length climbs, and that is a grading and sorting problem rather than a species problem. One more honest limit belongs in this list. There is no warranty on solid unmodified wood. It is not possible to warranty an organic material that responds to its environment, and any supplier offering one on a solid teak deck is selling something it cannot deliver.

"We can match the species, the cut and the grade, and we can keep a lot together across a job that gets pulled in phases. Nobody can sell you 60 years of weathering. The useful conversation is about where the new work sits next to the old, and whether the owner wants the repair to disappear now or five years from now."

Norm Moton, Director of Sales, J. Gibson McIlvain

Grade, Cut and Thickness on the Cutting List

Grade describes yield, not beauty, and a restoration cutting list that ignores the difference wastes grade on short parts and comes up short on long ones. Hardwood grading in North America runs on the National Hardwood Lumber Association rules, which grade a board by the yield of clear face cuttings it will produce.

FAS is the top grade. It requires a minimum board of 6 inches wide by 8 ft long yielding 83 and 1/3 percent clear face cuttings. FAS One Face, written F1F, meets FAS on the better face. Selects meet FAS on the better face at a smaller minimum size. No. 1 Common requires 66 and 2/3 percent clear face cuttings from a minimum board of 3 inches by 4 ft, and No. 2A Common requires 50 percent.

A No. 1 Common board is not a defective board. It yields smaller clear cuttings, which makes it the economical grade for short parts such as blocking, cleats, trim returns and cabin fillets, and the wrong grade for a deck plank or a caprail that has to run clear end to end. Long clear runs want FAS or better, and the specification should say so part by part rather than applying one grade to the whole list.

Thickness is quoted in quarters of an inch of rough thickness. 4/4 is nominal 1 inch rough, 8/4 is 2 inches, 16/4 is 4 inches, and every surfaced dimension comes off those rough numbers. Deck plank and caprail work usually starts thicker than the finished part so the resaw and the surfacer have material to work with. Imported teak does not arrive under an NHLA grade stamp, since those rules were written for North American species, so the controls on an import order are the written cutting list, the agreed cut and a physical inspection of the lot. The Wood Handbook from the Forest Products Laboratory covers the sawing geometry behind all of it.

Moisture Content for Wood That Lives Outdoors

A vessel is an exterior structure with an interior inside it, and the two halves of the boat want lumber dried to two different targets. Mixing them up is one of the few sourcing errors that shows up as a failure rather than as a complaint.

Kiln dried hardwood for interior use lands near 6 to 8 percent moisture content. Exterior work runs near 12 to 16 percent. Cabin joinery in a boat that gets heated through a northern winter belongs in the interior range. Deck planks, caprails, coamings, hatch surrounds and anything else that lives in the weather belongs in the exterior range, and dropping that material to an interior figure sets it up to swell once it goes back outside.

Air dried stock settles near the local equilibrium moisture content and is not a substitute for kiln dried material where an interior tolerance matters. Plenty of boatyards keep air dried oak on hand for bent frames, which is a legitimate use. It is not the same thing as a dried, graded, measured lot for joinery. Building Science Corporation's digest on moisture and materials explains the equilibrium behavior underneath both targets.

J. Gibson McIlvain mills and dries to both of those targets and records which one a lot was dried to, so the shipwright setting the deck knows what arrived rather than guessing from the feel of the board. Where a part is going to be bent, steamed or laminated, the yard should say so on the order, since that part has its own moisture requirement and should not be pulled from the same lot as the trim.

Species That Do the Teak Job Honestly

When teak will not come in the size, the grade or the length a part needs, the honest alternatives are Iroko, Afrormosia, Sapele and Utile. All four are worked daily in millwork, all four machine and glue predictably, and all four come in a size range teak no longer reliably offers.

Iroko has served as the working substitute for teak in boat trim and exterior joinery for generations. It is durable, it weathers to a similar grey, and it holds up in exposed detail. The interlocked grain demands sharp tooling and a slower feed, and the color starts browner and more variable than teak. Afrormosia is the closer match in working feel and in finished appearance, with a finer, more even texture, and it takes a bright finish well.

Sapele sits at roughly 1,410 lbf on the Janka scale and comes in a wider range of sizes and longer lengths than Genuine Mahogany at roughly 800 lbf. For painted exterior trim Sapele is the better call, since it holds paint better and the size range is there. Open-grained and oily species absorb a great deal of finish, so a primer coat evens out the eventual painted surface, and sanding or buffing after priming knocks back the raised grain while keeping any moulded detail crisp. Sapele is not milled 1x8 for exterior use, since that width is too wide to stay stable, and cupping in service is driven by installation and back ventilation rather than by the species on the invoice.

Utile, sold as Sipo, is the quieter cousin of Sapele, with straighter and less busy figure, which suits cabin panel work and door and frame stock. Genuine Mahogany remains the period correct choice for cabin joinery and brightwork on a great many classic builds, and many restoration committees insist on it below decks even while the exterior trim goes to Sapele.

Buyers coming off a decking project ask about the tropical decking species, Ipe, which is Tabebuia spp, along with Cumaru, Garapa, Jatoba and Red Balau. They are extremely hard and carry high oil content, which makes them difficult to glue, and that is exactly the wrong set of properties for parts that get laminated, bent, bunged or bedded into an assembly. A millwork shop reaches for Teak, Iroko, Afrormosia, Sapele or Utile on machined and glued components for that reason, and leaves the decking species to decking.

J. Gibson McIlvain holds over seven million board feet of exotic and domestic lumber at its Maryland yard, which is what makes lot matching across a long parts list realistic instead of aspirational. Pulling 40 caprail blanks that agree on color and grain is a sorting problem, and sorting requires volume to sort through.

Cedar, Oak and the Domestic Stock Around the Teak

Most of a classic hull is not teak, and the domestic species around it carry more of the structural load than the brightwork does. A sourcing plan that only solves the teak question has solved the visible third of the job.

White Oak at roughly 1,360 lbf is the traditional frame, floor and keel species in North American wooden boatbuilding. Red Oak at roughly 1,290 lbf is a fine interior and trim wood, and its open pore structure is the reason it is not the choice for structure that stays wet. The two are not interchangeable on a boat even though a grading rule treats them as close cousins.

White Ash at roughly 1,320 lbf bends well and shows up in tillers, oars, rails and interior bent work. Black Walnut at roughly 1,010 lbf and Cherry at roughly 950 lbf both belong to cabin joinery on builds where the original joiner used them. Yellow Poplar at roughly 540 lbf is the pattern and mold wood, cheap to cut, stable enough to loft from, and never intended to end up in the finished boat.

Cedar earns its place here on real merit. Western Red Cedar is the strip planking and cold molded hull species for good reason, light, stable and naturally durable, and the grade call matters more than the species call. CVG, clear vertical grain, is what a hull plank or a long exterior run wants. STK, select tight knot, is the right and economical specification where sound tight knots are acceptable and the part is short. Specifying cedar without specifying the grade is how a yard ends up with the wrong material and blames the wood. The Wood Database entries for White Oak and Western Red Cedar carry the mechanical figures for both.

Where Modified Wood Fits and Where It Stops

Modified wood solves a dimensional stability problem, and it does not solve a period correctness problem. It belongs in the shoreside and painted parts of a restoration project, not in the bright finished fabric a survey is judging.

Accoya is acetylated softwood, roughly 1,600 lbf on the Janka scale, with dramatically reduced shrinkage and swelling and excellent paint holding. Thermory and Abodo Vulcan are both carried as thermally modified options. All three have real uses around a boat program, in painted exterior detail, a dock structure, a boathouse or a shoreside building where stability under weather exposure is the governing requirement.

The limits are hard and worth knowing before a drawing commits to them. Modified products top out around 16 ft, and most are sold on metric lengths just under 16 ft, because of kiln size. Thermally modified Ash is not available wider than 8 inches, so a specification calling for wide boards in a modified product means Accoya or Abodo Vulcan rather than modified Ash.

One commercial difference matters. Warranties exist on modified products and on nothing else. Solid unmodified wood cannot be warrantied, which is not a dodge but a plain statement about an organic material responding to humidity, sun and salt. Where a client wants a warranty on an exterior element, the material has to be a modified product and the element has to be one a modified product can honestly serve.

Documentation That Travels With Imported Teak

On imported teak, the paperwork is part of the material, and a lot without it is a liability rather than a bargain. Species identification, country of harvest and chain of custody are what let a yard, an insurer or a preservation body accept the material without argument.

J. Gibson McIlvain is an FSC certified importer and miller, so documentation and chain of custody travel with the material rather than being reconstructed after the fact. On a species with a complicated supply picture, that record is the difference between a restoration that can state where its teak came from and one that cannot.

A restoration under review by a preservation body gets held to a repair in kind standard before replacement. The treatment standards the National Park Service publishes for historic fabric were written for buildings, and the logic transfers cleanly to a vessel, retain what can be retained, repair what can be repaired, and replace in kind only what is gone. That logic is also what drives species and cut matching back up the order to the supplier, since repair in kind is a material specification and not just a philosophy.

Ordering, Lot Matching and Getting It to the Yard

A restoration order is a sequence of releases against one reserved lot, not a single pull off the rack. Teak, Iroko and Afrormosia all show enough color and grain variation that mixing two purchases inside one visible assembly will read as two purchases.

The practical move is to agree the whole parts list up front, reserve the material, then release it in phases against the shipwright's schedule. J. Gibson McIlvain records the species, cut, grade and thickness on the order so a second release months later matches the first. J. Gibson McIlvain also ships nationwide, regularly to California, which is how a West Coast boatyard buys East Coast stock without rolling the dice on freight.

Rough mill work before shipping takes a large bite out of what the boatyard has to do to thick import stock. Band resaws take 8/4 and 16/4 teak down toward plank and panel thickness, straight line and gang rip saws put a true edge on a long run, trimming saws break material down to usable length, and moulders run caprail and handrail profiles. J. Gibson McIlvain resaws and rips the rough stock so the boatyard receives material closer to its finished section instead of paying a joiner to hog it away by hand.

The same mill also feeds ICD, the company's architectural millwork division, which builds true custom case work planned around a specific space, and the panel, stile and rail stock a cabin fit-out needs comes out of that same material stream. What stays with the boatyard is everything from the fit onward. Scarfing, bedding, caulking the seams, bunging over fasteners, fairing and finishing are the shipwright's craft and the shipwright's measurements, and no lumber supplier should be writing those tolerances from a distance.

How J. Gibson McIlvain Would Specify This

A teak order that holds up under a surveyor's eye names the species, the cut, the grade, the thickness in quarters, the moisture target and the delivery sequence, part by part. Everything on that list is a decision someone will make, and the only question is whether it gets made on the order or at the dock.

Start with the parts list and assign a grade to each line rather than to the whole order. Long clear deck planks, caprails and coamings get FAS or better in quartersawn teak. Short parts, blocking and anything that will be covered get No. 1 Common, which is the economical grade for exactly that work. Thickness gets written in quarters off the rough, with enough over the finished section for resawing and surfacing.

Set the moisture target by where the part lives, 6 to 8 percent for heated cabin joinery and 12 to 16 percent for everything in the weather, and put the target on the order so the lot can be measured against it on arrival. Where teak will not come in the size or the clear length a part needs, substitute deliberately and on the record, Afrormosia or Iroko for exterior trim, Sapele for painted work, Utile or Genuine Mahogany for cabin joinery, Western Red Cedar in CVG for hull planking.

Then write down what will not be matched. The patina on the original deck, the ring density of old growth stock, and any original plank wider or longer than current supply allows. An owner who hears that in advance accepts a repair that will blend over several seasons. An owner who hears it after delivery calls the material wrong.

J. Gibson McIlvain mills, dries and sorts the material for work like this and will review a parts list against what the yard actually holds before anyone commits a drawing to it. The millwork and lumber services page covers what comes off the floor, and a call to 800-638-9100 gets a cutting list reviewed, graded and scheduled against the restoration's phases.

Frequently Asked Questions

Where can a yard source teak for a classic sailing vessel restoration?

From an importer that stocks the species in depth, grades to a written cutting list and can hold a lot together while the job is pulled in phases. The order needs to state species, cut, grade by part, thickness in quarters off the rough and a moisture target, not just the word teak. J. Gibson McIlvain mills, dries, grades and sorts hardwood for restoration work and will look at a parts list before a drawing commits to it, at 800-638-9100.

Can new teak be matched to a 90 year old deck?

Not on day one. The silver grey on an original deck is decades of ultraviolet exposure, salt and scrubbing, and new teak starts honey brown and weathers on its own schedule. Species, cut and grade can be matched exactly. The color of a repair blends over several seasons, and an owner who expects that in advance is far happier than one who learns it at delivery.

Is plantation teak acceptable on a restoration?

It depends on the part. Plantation logs show wider growth rings, a larger share of sapwood and more color variation board to board, so the material works where parts are short, covered or painted and struggles where a long clear quartersawn run has to look original. Specify the part and let the grade and the cut decide, rather than accepting or rejecting the whole category.

What is the best substitute for teak on a classic boat?

Iroko and Afrormosia for exterior trim and bright finished detail, Sapele for painted exterior work and long clear runs at roughly 1,410 lbf, Utile, which is sold as Sipo, for cabin panel and frame stock, and Western Red Cedar in CVG for hull planking. The tropical decking species are a poor fit here, since they are extremely hard and carry high oil content, which makes them difficult to glue in a bedded or laminated assembly.

Does teak come with a warranty?

No. Warranties exist on modified products such as Accoya, Thermory and Abodo Vulcan, and on nothing else. It is not possible to warranty solid unmodified wood, which is an organic material that responds to humidity, sun and salt. Any supplier offering a warranty on a solid teak deck is promising something outside its control.

What moisture content should restoration lumber arrive at?

Near 6 to 8 percent for cabin joinery in a boat that gets heated, and near 12 to 16 percent for deck planks, caprails, coamings and anything else in the weather. Air dried stock settles near the local equilibrium and is not a substitute for kiln dried material where an interior tolerance matters, though air dried oak remains a legitimate choice for bent frames.

How thick should teak be ordered for deck planks?

Thicker than the finished part. Rough thickness is quoted in quarters, so 4/4 is nominal 1 inch rough, 8/4 is 2 inches and 16/4 is 4 inches, and every surfaced dimension comes off those rough numbers. Band resaws take 8/4 and 16/4 stock down toward plank thickness, and the boatyard should set the finished section since it is the one fairing and bedding the deck.

Why does imported teak not carry an NHLA grade stamp?

The National Hardwood Lumber Association rules were written for North American hardwoods, and they grade a board by the yield of clear face cuttings it produces. Imported teak trades on export grade descriptions instead, so the real controls on the order are a written cutting list, an agreed cut such as quartersawn, and a physical inspection of the lot before it ships.

Sources and Standards Referenced

• National Hardwood Lumber Association
• Wood Handbook, Wood as an Engineering Material, USDA Forest Products Laboratory
• The Wood Database, Teak
• Building Science Digest 138, Moisture and Materials
• Forest Stewardship Council
• National Park Service, The Four Treatments for Historic Properties
• Accoya Modified Wood
• Thermory Thermally Modified Wood