Technical Overview of Berlinia for Wood and Epoxy Tabletops
Berlinia represents a group of African hardwood species—including Berlinia bracteosa, Berlinia confusa, Berlinia grandiflora, and related species—often evaluated for fine furniture, heavy carpentry, and decorative interior builds. When designing an epoxy river table or wood-and-epoxy countertop, understanding how a species responds to moisture, cutter heads, and mechanical loads is essential for achieving a long-lasting, flat surface. The following technical breakdown is based directly on mature wood data published in the CIRAD Tropix technical sheet for Berlinia.
| Property | CIRAD Tropix value | What it means / US units |
|---|---|---|
| Botanical name(s) | Berlinia bracteosa, Berlinia confusa, Berlinia grandiflora, Berlinia p.p. | |
| Colour / texture / grain | Pinkish brown; texture medium; grain straight or interlocked; interlocked grain slight | |
| Specific gravity (12% MC) | 0.70 | about 43.7 lb/ft³; a 2-inch-thick slab weighs about 7.3 lb per sq ft |
| Monnin hardness (12% MC) | 4.0 | French hardness scale; higher = harder (not a Janka value) |
| Total tangential shrinkage | 7.8 % | green to oven-dry |
| Total radial shrinkage | 3.8 % | green to oven-dry |
| Ratio St/Sr | 2.1 | closer to 1 = less cupping tendency |
| Coefficient of volumetric shrinkage | 0.53 % per % MC | volume change per 1% change in moisture content |
| Fibre saturation point | 28 % | |
| Thermal conductivity | 0.23 W/(m·K) | |
| Crushing strength (12% MC) | 57 MPa | about 8,270 psi |
| Static bending strength (12% MC) | 93 MPa | about 13,490 psi |
| Modulus of elasticity (12% MC) | 12,870 MPa | about 1,867,000 psi |
| Decay (fungi) resistance | Durability class 3 – moderately durable | |
| Termite resistance | Class M – moderately durable | |
| Dry-wood borer resistance | Class D – durable (sapwood demarcated, risk limited | |
| Heartwood treatability | Class 3 – poorly permeable | |
| Use class from natural durability | Class 2 – inside or under cover (dampness possible) | |
| Drying | rate normal to slow; distortion: slight risk; checking: no risk or very slight risk; collapse: no known specific risk; casehardening: no known specific risk | |
| Suggested kiln program temperatures | 53–65 °C | about 127–149 °F |
| Machining | blunting normal; saw teeth: ordinary or alloy steel; cutting tools: ordinary | |
| Nailing and screwing | Good but pre-boring necessary | |
| CITES status | This species is not listed in the CITES Appendices (Washington Convention 2025). |
Values from the CIRAD Tropix technical sheet (average values for mature wood, 12% moisture content where noted). US-unit conversions are calculated by BigEpoxy (1 MPa = 145.04 psi; density = specific gravity × 62.43 lb/ft³).
What does Berlinia wood look like, and how does its grain present in slabs?
Berlinia heartwood displays a warm pinkish brown color reference, frequently accented by dark brown or purple veins that create striking visual interest in wide slabs. The wood texture is medium, and the grain runs straight or slightly interlocked. CIRAD Tropix also notes the presence of frequent resin canals throughout the wood structure. For builders working with live-edge materials, log diameters typically range from 60 to 90 cm (roughly 24 to 35 inches), with a clearly demarcated sapwood band that measures between 10 and 15 cm (about 4 to 6 inches) in thickness.
How heavy is a Berlinia slab, and how hard is the wood?
Berlinia is a medium-to-heavy hardwood with an average specific gravity of 0.70 at 12% moisture content. In workshop measurements, this translates to an average density of approximately 43.7 lb/ft³. A standard 2-inch-thick tabletop slab weighs about 7.3 lb per square foot before pouring epoxy. Its structural strength ratings at 12% moisture content include a crushing strength of 57 MPa (about 8,270 psi), a static bending strength of 93 MPa (about 13,490 psi), and a modulus of elasticity of 12,870 MPa (about 1,867,000 psi).
Hardness is recorded at 4.0 on the Monnin hardness scale. Monnin is a standardized French testing scale where higher numbers reflect harder wood; it is not equivalent to the American Janka test and should never be mathematically converted to Janka values.
How does Berlinia behave next to an epoxy river in terms of shrinkage and movement?
In an epoxy river table, managing dimensional movement between the cured resin core and the adjacent wood borders is critical. Berlinia has a fibre saturation point of 28%. When transitioning from green to oven-dry conditions, its total tangential shrinkage is 7.8%, while total radial shrinkage is 3.8%. This produces a tangential-to-radial shrinkage ratio (St/Sr) of 2.1 and a coefficient of volumetric shrinkage of 0.53% per 1% change in moisture content.
Because tangential movement is roughly double the radial movement, quartersawn boards offer greater dimensional stability than flatsawn slabs along the epoxy boundary. CIRAD Tropix specifically notes that quartersawn drying is recommended to minimize distortion.
What are the drying characteristics and defect risks for Berlinia?
The drying rate for Berlinia is classified as normal to slow. When it comes to seasoning defects, the technical data shows no risk or very slight risk of checking, with no known specific risks for collapse or casehardening. However, there is a slight risk of distortion. Recommended kiln schedules utilize drying temperatures ranging from 53 °C to 65 °C (approximately 127 °F to 149 °F), starting at high relative humidity (around 85% to 87%) when wood moisture is above 50%, followed by gradual conditioning down to target moisture levels.
How easily does Berlinia machine, cut, and hold fasteners?
In the shop, Berlinia exhibits a normal blunting effect on tooling. Sawing can be completed with ordinary or alloy steel saw teeth, and profile work can be handled with ordinary cutting tools. Both peeling and slicing operations yield good results. For structural joinery, aprons, and mechanical mounting bases, nailing and screwing properties are rated as good, though pre-boring is strictly necessary to prevent splitting.
What is Berlinia’s natural durability and insect resistance?
Berlinia heartwood offers moderate natural protection against biological threats:
- Fungi resistance: Durability class 3 (moderately durable).
- Dry-wood borers: Class D (durable; sapwood is clearly demarcated and risk is limited strictly to sapwood).
- Termites: Class M (moderately durable).
- Treatability: Class 3 (poorly permeable).
Based on these natural durability characteristics, Berlinia heartwood provides Class 2 performance (interior use or under cover where dampness is possible). The technical sheet states that preservative treatment is required if the wood experiences temporary humidification, and its use is not recommended in cases of permanent humidification.
Is Berlinia restricted under international trade agreements?
Berlinia is not listed in the CITES Appendices under the Washington Convention (2025 update). Slabs and lumber of these botanical species can be acquired and traded without CITES restriction documentation.
What are the standard furniture and architectural end-uses for Berlinia?
The CIRAD Tropix sheet lists a wide variety of commercial and fine-woodworking applications for Berlinia. Recognized uses include cabinetwork (high-class furniture), current furniture or furniture components, interior joinery, exterior joinery, flooring, interior panelling, exterior panelling, indoor staircases, wood-ware, turned goods, sliced veneer, formwork, carpentry, and veneer for plywood faces or backs.
Sources
Published October 30, 2026. Sources are linked in the text.
Header image: original graphic by BigEpoxy.com.
Staff note: CIRAD Tropix notes that physical and mechanical properties vary significantly among the different species commercially grouped under Berlinia (also called Ebiara), making it essential to evaluate each slab individually for density and grain straightness before finalizing tabletop joinery. (Source: CIRAD Tropix 7 technical sheet: Berlinia.)