Some marine timbers are chosen for brute strength. Bilinga wood, also known as opepe, is chosen for something just as valuable: a long record of surviving in water, including salt water where marine borers destroy many other species. Add a bright golden-orange colour, good stability and a sensible price, and you can see why engineers and landscape architects keep coming back to it.
In this guide we explain what bilinga is, where it performs best, how it compares with other marine timbers, how to work it and what it costs. We supply bilinga from Cameroon, Gabon and the Republic of Congo at Global Timber Trade Hub.
In short
- Bilinga (opepe) is a very durable African hardwood with a golden-orange colour.
- It has a good record against marine borers, unusual among African timbers.
- It is used for jetties, piles, lock gates, decking, boardwalks and cladding.
- It is lighter than Azobe, so it is easier to handle on site.
- It is not CITES listed, which keeps paperwork simple.
- Our bilinga starts from about $700 per m³, FOB Central Africa.
What is bilinga?
Bilinga comes from Nauclea diderrichii, a large tree of West and Central Africa. In the UK it is best known as opepe; in France and Central Africa, as bilinga; in other markets, as badi or kusia. The trees grow tall and straight, giving long, clear logs.
The heartwood is a bright yellow to golden-orange, darkening to a warm orange-brown with exposure. The grain is interlocked, often giving an attractive stripe on quartersawn faces. The texture is medium to coarse.
Bilinga wood properties
| Property | Bilinga |
|---|---|
| Density at 12% MC | about 720–780 kg/m³ |
| Janka hardness | about 1,600 lbf |
| Natural durability | Very durable |
| Marine borer resistance | Good |
| Stability | Good once dried |
| CITES | Not listed |
Why bilinga stands out for marine work
Many dense African hardwoods resist fungal decay well in fresh water. Fewer resist marine borers, such as shipworm and gribble, which attack timber in salt and brackish water. Bilinga has a long, documented record of good performance in these conditions. That is why it has been used for harbour works, jetties and sea defences, especially in the UK and France.
For warm tropical seas with very high borer pressure, engineers sometimes still prefer Greenheart or add protection. Our guide to Azobe vs Greenheart explains this in more detail.
Best uses for bilinga wood
Jetties, piers and pontoons
Bilinga is used for piles, beams and deck boards in jetties and marinas. Its lighter weight compared with Azobe makes installation easier. See our guide to the best wood for marine construction.
Lock gates and sluices
Bilinga is a proven lock gate timber, combining durability, stability and good availability in large sections.
Decking and boardwalks
Its golden colour and durability make bilinga a popular decking choice for coastal promenades, pontoons and gardens. See the best hardwood for decking.
Cladding and facades
Bilinga cladding weathers evenly to a soft grey, with good stability and no need for treatment. See our guide to hardwood cladding.
Bridges and landscape structures
Footbridges, steps, retaining walls and bank protection all benefit from bilinga’s durability.
Flooring and joinery
Indoors, bilinga makes a bright, hard-wearing floor. It is also used for exterior doors, sills and window parts.
Bilinga vs other marine timbers
| Species | Density (kg/m³) | Borer resistance | Weight on site | From (USD/m³) |
|---|---|---|---|---|
| Bilinga | 720–780 | Good | Moderate | $700 |
| Azobe | 1,000–1,100 | Moderate | Very heavy | $650 |
| Okan | 880–950 | Moderate | Heavy | $650 |
| Tali | 880–930 | Moderate | Heavy | $650 |
| Greenheart | 950–1,050 | Good | Very heavy | Higher |
Borer resistance ratings are general guides. Always follow your engineer’s assessment for the specific site.
Drying and stability
Bilinga dries fairly slowly and can develop surface checks and end splits if rushed. Heavy marine sections are usually supplied fresh sawn or air dried. Decking and cladding are dried more carefully. Once dry, bilinga is reasonably stable. Seal cut ends on site to reduce splitting.
Working with bilinga
- Machining: machines reasonably well; interlocked grain can tear out on planing.
- Tooling: use carbide for production work.
- Fixings: pre-drill and use stainless steel or hot-dip galvanised fixings.
- Gluing: glues satisfactorily for non-structural uses.
- Finishing: takes oil and exterior coatings well; often left to weather.
- Dust: use extraction and a mask.
Colour and weathering
Fresh bilinga is a vivid golden-orange. Within months it mellows to a warm orange-brown, and outdoors, unfinished, it weathers to silver-grey. If you want to keep the golden tone on a deck, use a pigmented UV-protective oil and reapply regularly. For cladding, most architects let it grey naturally.
Bilinga wood price
Our bilinga starts from about $700 per m³ for standard sawn sections, FOB Central Africa. Long and large sections, decking profiles and dried stock cost more. See our African hardwood prices guide for comparisons.
Sizes and product forms
- beams and baulks up to about 300 × 300 mm, lengths up to about 12 m;
- planks and decking 21–60 mm thick;
- cladding boards to your profile;
- piles where log export is legally allowed;
- custom cutting lists for engineered structures.
Legality and sustainability
Bilinga is not CITES listed. We buy only from concessions with valid harvesting permits and supply legality and chain-of-custody documents with every shipment, which support due diligence under EUDR, the UK Timber Regulation and the Lacey Act. Read more on our sustainability page.
How to specify bilinga
For marine and structural projects, include the strength class, grading standard, section sizes, lengths and tolerances, moisture condition, allowed defects and legality requirements. For decking and cladding, give the profile, thickness, width, length range and finish. If your project allows equivalent species, list them; it often improves lead times.
A typical bilinga project
A coastal town replaces the deck of its fishing pier. The old softwood deck lasted only a few years. The engineer specifies bilinga for the new deck boards and handrails because of its durability and borer record, and keeps the existing concrete piles. The golden deck becomes a local landmark, then slowly weathers to a calm silver-grey that suits the seafront.
Common mistakes with bilinga
- Kiln drying heavy sections: it often causes more checking than air drying.
- Using plain steel fixings: they corrode in marine air.
- Not sealing ends: end splits are the most common small defect.
- Expecting the orange colour to last: it mellows and greys unless oiled.
Bilinga for landscape architects
Landscape architects like bilinga for its warm colour, durability and moderate weight. It is used for park bridges, raised walkways through wetlands, steps, seating, planters and riverbank edges. Unlike the heaviest marine timbers, bilinga sections can often be handled with lighter equipment, which matters on sensitive sites with limited access. Over time it weathers to a soft grey that blends with stone, gravel and planting.
Lead times for bilinga
Standard sections and decking are often available within a few weeks. Long beams, large sections and custom profiles usually take 4–8 weeks before loading. Because bilinga is not CITES listed, there is no permit waiting time. For large public projects, we can split deliveries to match your construction phases.
Bilinga cladding: practical tips
Bilinga cladding gives buildings a warm golden face that slowly turns silver. For the best result, use boards 18–25 mm thick, kiln or air dried to suit your climate, with a profile that sheds water such as shiplap or open-jointed boards on battens. Leave a ventilated cavity of at least 20 mm behind the boards, fix with stainless steel screws or nails, and pre-drill near the ends. Expect some colour variation between boards at first; it evens out as the facade weathers.
Bilinga decking: installation tips
For decks, boards of 21–28 mm on joists at 400–500 mm centres suit most residential and commercial uses. Leave 5–8 mm gaps between boards, ventilate the space below and pre-drill every screw hole. Near the sea, use A4 stainless steel. Sealing cut ends on site reduces end checks. Bilinga can be left to grey naturally or oiled to keep its colour.
Quality checks before loading
For every bilinga order, we check section sizes and lengths against your list, measure moisture on a sample, inspect for splits, sapwood and heart, and photograph each bundle. For structural orders, we can arrange grading to the strength class your engineer specifies. The packing list shows the volume and number of pieces in every bundle.
Is bilinga right for your project?
Choose bilinga when you need a very durable, attractive timber for marine and outdoor work, especially where borer risk or site handling makes the heaviest species less practical. For the very heaviest loads and abrasion, Azobe or Okan may be better. For fine indoor furniture, a finer-textured wood will serve you better. Tell us about your project, and we will suggest the right species for each part.
Bilinga in mixed marine orders
Marine contractors often combine species in one shipment: Azobe or Okan for fender piles that take the hardest knocks, bilinga for walers and deck beams, and bilinga or Iroko for the walking surface and handrails. Each bundle is labelled and listed separately, so the site team can find what they need. This approach keeps freight costs down and puts the right timber in the right place, rather than paying for the heaviest species everywhere.
Sources
- Nauclea diderrichii on Wikipedia
- CIRAD Tropix for technical data.
Related guides
- Best wood for marine construction
- Hardwood cladding
- Okan vs azobe
- Heavy construction and marine timber
- Best hardwood for decking
Frequently asked questions about bilinga wood
Is bilinga the same as opepe?
Yes. Bilinga and opepe are trade names for Nauclea diderrichii.
Is bilinga good in salt water?
Yes. It has a good record against marine borers and is used for jetties and harbour works.
Is bilinga good for decking?
Yes. It is very durable, attractive and lighter than Azobe, which makes installation easier.
How much does bilinga cost?
Our bilinga starts from about $700 per m³, FOB Central Africa.
Get a quote for bilinga
Send your cutting list or bill of quantities through our quote form. We will reply with a firm price, lead time and the documents your project needs.