Hardwood decking species
Doju Decking
Ipe hardness, better stability, no CITES paperwork.
Doju matches Ipe’s 3,680 Janka and beats it on dimensional stability, at meaningfully less per lineal foot — and it carries no CITES listing, so lead times don’t swing with permit season. If you want Ipe performance and can live with an olive-brown rather than a near-black board, this is the one to look at.
Doju is a dense South American hardwood — genus Buchenavia, sometimes sold as Bolivian Walnut — that has been traded in Europe for decades under its own name rather than as a substitute for anything else. It is a close cousin to Ipe, and on the two numbers people actually check it either matches or beats it: 3,680 lbf on the Janka scale, identical to Ipe, and dimensional stability that is meaningfully better.
The heartwood is light to dark olive brown with contrasting yellowish-grey and grey-brown tones running through it — a different look from Ipe’s near-black, and one a lot of people prefer once they see a board in daylight. Left untreated it ages to a lustrous silver-grey; oiled, it holds a rich golden-brown.
The practical argument for Doju is supply. It carries no CITES Appendix II listing, so there are no export permits to wait on and no permit-season price swings — the thing that has made Ipe hard to plan around since 2022. The resource sits concentrated in the northeast corner of South America under long-standing supply arrangements, which is why availability stays steady while Ipe comes and goes.
Ghent stocks Doju as kiln-dried 5/4x4 and 5/4x6 deck boards, S4S with eased edges, in even lengths from 8′ to 20′, priced by the lineal foot.
Why Doju is worth a look
As hard as Ipe
Doju tests at 3,680 lbf on the Janka scale — the same figure as Ipe, and roughly four times pressure-treated pine. Foot traffic, furniture and dog claws do not mark it.
More stable than Ipe
Radial shrinkage of 3.6% and tangential of 5.1%, against Ipe’s 6.6% and 8.0%. That is why it is the better choice close to the ground and in climates that swing hard between seasons — the boards simply move less.
No CITES listing
Unlike Ipe and Cumaru, Doju needs no export permit. No permit-season delays, no paperwork, and a price that does not lurch when a source country changes its process.
Very durable, untreated
Rated very durable, resistant to both brown- and white-rot fungi, with what the testing literature calls exemplary weathering characteristics. Nothing is added to it.
A colour of its own
Olive brown with yellowish-grey and grey-brown contrast rather than Ipe’s uniform near-black. It reads warmer, and the figure is more visible in the finished deck.
Long boards
Even lengths through 20′, which on most residential decks means running the full span with no butt joint at all.
Warrantied for 25 years
A 25-year manufacturer warranty against rot and decay, provided the installation guidelines are followed — and Ghent stands behind it, so the cover does not depend on the manufacturer still being in business in 2050.
Doju vs. the alternatives
Doju against the species buyers cross-shop it with. The numbers that matter here are the two on stability — Doju is the most dimensionally stable board on this table, which is the whole reason to choose it over Ipe.
| Doju | Cumaru | Golden Balau | Composite | PT Pine | |
|---|---|---|---|---|---|
| Janka hardness | 3,680 lbf | ~3,200 lbf | ~1,800 lbf | n/a (plastic) | ~870 lbf |
| Radial shrinkage | 3.6% — best here | 5.4% | 4.2% | Inert | ~4.8% |
| Tangential shrinkage | 5.1% — best here | 8.4% | 9.3% | Inert | ~7.5% |
| Density | 950 kg/m³ | 1,080 kg/m³ | 930 kg/m³ | n/a | ~600 kg/m³ |
| Rot / insect resistance | Very durable | Very durable | Durable | Inert | Chemically treated |
| CITES Appendix II | No | Yes | No | n/a | No |
| Relative cost | $$$ | $$$ | $$ | $$$ | $ |
| Close-to-ground use | Excellent — the stability case | Poor | Good | Good | Fair |
Buying Doju decking
- Profiles: 5/4x6 (net 1″ × 5-1/2″) is the standard residential deck board; 5/4x4 (net 1″ × 3-1/2″) gives tighter board lines and behaves better on curves and small landings.
- Grade: First Clear, kiln-dried, S4S with eased edges.
- Lengths: even lengths 8′ through 20′. Order a tally of mixed lengths and most decks run with no butt joints.
- Coverage: 5/4x6 covers 5-1/2″ (about 0.46 SF per lineal foot); 5/4x4 covers 3-1/2″ (about 0.29 SF per LF). The tally calculator on each product page totals feet, coverage and price as you build the order.
- Sample boards are $5 — worth ordering, because olive-brown-with-grey-contrast is not a colour anyone can judge from a photograph.
Installation
- Pre-drill and countersink every face fastener. At 950 kg/m³ and 3,680 Janka, a screw driven straight in will split the board or snap off. Use stainless steel.
- Acclimate on site before fastening anything — stacked, stickered, out of direct sun and weather. Doju is stable, but no hardwood should be installed straight off the truck.
- Gap 3/16″–1/4″ for drainage and seasonal movement, and keep air moving under the deck.
- Seal fresh end cuts with a wax-based end sealer; every cut opens end grain the mill had already sealed.
- Doju’s stability makes it one of the few tropical hardwoods genuinely suited to close-to-ground decks, where drying from below is limited — but ventilate as well as the site allows regardless.
Maintenance & finishing
- Do nothing and Doju ages to a lustrous silver-grey with no loss of strength or durability.
- To hold the golden-brown, use a penetrating oil finish with UV inhibitors, such as ExoShield Tung Oil, and re-coat every one to three years depending on exposure.
- Cleaning and re-oiling restores the colour without sanding or stripping, as many times as you like over the deck’s life.
Sourcing & sustainability
- Doju carries no CITES Appendix II listing — unlike Ipe and Cumaru, it needs no export permit and no source-country documentation beyond the usual.
- Our Doju is legally harvested and legally sourced under the U.S. Lacey Act and the corresponding South American authority, under exclusive supply arrangements that control the harvest rather than chasing whatever is available.
- Selective logging with long return cycles gives the forest time to regenerate. Doju trees reach 140–150 feet with trunks up to 6 feet across; the average is nearer 100 feet and 2–3 feet, and they grow in marsh forest, ridge top and riverbank across the Lesser Antilles and tropical America.
Doju decking — frequently asked questions
What is Doju wood?+
Doju is a dense South American hardwood of the genus Buchenavia, also sold as Bolivian Walnut. It has been traded in Europe for decades and is a close cousin to Ipe — same 3,680 lbf Janka hardness, better dimensional stability, olive-brown rather than near-black.
Is Doju as good as Ipe?+
On hardness they are identical at 3,680 lbf. On stability Doju is better — 3.6% radial and 5.1% tangential against Ipe’s 6.6% and 8.0%. Ipe is denser and carries a Class A fire rating; Doju costs less per lineal foot and carries no CITES listing. For most residential decks the trade is a good one.
Is Doju CITES listed?+
No. Ipe went onto CITES Appendix II at the end of 2022 and now needs export permits for every shipment. Doju does not, which is why its availability and price have stayed steadier.
What colour is Doju and does it change?+
Light to dark olive brown with contrasting yellowish-grey and grey-brown tones. Left untreated it weathers to a lustrous silver-grey; oiled it holds a rich golden-brown. The choice is reversible at any point.
Can Doju be used close to the ground?+
It is one of the better tropical hardwoods for it. Low-clearance decks dry poorly from below, so dimensional stability matters more there than anywhere else — and Doju is the most stable board we stock.
Do I have to pre-drill Doju?+
Yes, for every face fastener. It is as hard as Ipe, and an undrilled screw will split the board or snap. Pre-drill and countersink with stainless-steel screws.
What sizes and lengths do you stock?+
5/4x4 and 5/4x6 deck boards, First Clear grade, S4S eased edge, kiln-dried, in even lengths from 8′ to 20′. Priced by the lineal foot.
How long does a Doju deck last?+
Doju is rated very durable against brown- and white-rot fungi with exemplary weathering characteristics, so a well-built, well-drained deck should last decades untreated. Drainage, gapping and airflow drive the number as much as the species does.
Doju or Golden Balau?+
Doju is far harder (3,680 vs 1,798 Janka) and much more stable, and it costs more. Golden Balau is the value tropical hardwood; Doju is the one to pick when you want Ipe-class performance. Both are free of CITES paperwork.
Is there a warranty on Doju decking?+
Yes — 25 years against rot and decay, from the manufacturer, provided the installation guidelines are followed. Ghent stands behind it as well: if the manufacturer is ever not there to honor a claim, we will. The same applies to Ipe, Yellow Balau and Red Balau.
Can I get a sample?+
Yes — $5 from either Doju product page. Recommended: the olive-brown-and-grey contrast is genuinely hard to judge from a screen.
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