Sweet Chestnut
Castanea sativa
Also known as Spanish chestnut, European chestnut · Botanical Castanea sativa
Revision history
- — Data re-verified in site-wide audit (formulas, sources, durability classes)
- — Working properties and comparable-species data cross-checked against listed sources
About Sweet Chestnut
Sweet Chestnut (Castanea sativa) is a soft timber that works easily but bruises and dents in service, with a Janka hardness of 680 lbf (3,025 N) and a density of about 0.56 g/cm³. It grows in Europe.
At 4.2% radial and 6.9% tangential the T/R ratio is 1.64 — typical, and manageable in exterior joinery and cladding provided the gaps are designed rather than assumed. Its fibre saturation point is near 28%. Below it the wood shrinks steadily — 6.9% tangential, 4.2% radial. Ordinary territory: design the gaps rather than hoping the finish will hold it.9% tangential against 4.2% radial, quartersawn stock will behave noticeably better than flatsawn.
At 560 kg/m³ a cubic metre of Sweet Chestnut weighs about 560 kg air-dry — that figure, the 6.9% tangential and 4.2% radial movement and the 680 lbf hardness are the three inputs the calculators below actually consume. Select Sweet Chestnut in any of them to get species-specific results for weight, moisture, shrinkage and hardness.
Working properties
How Sweet Chestnut behaves at the bench and on the machine, drawn from European cladding-timber technical data and peer-reviewed durability research.
Durability & use classification
Sweet Chestnut heartwood is rated durable (EN 350 Class 2) — its high tannin content (roughly 8–15% extractives) is what drives that resistance to fungal decay and insects, and it needs no preservative treatment. Two honest cautions: the sapwood is perishable and must be excluded, and published research records real variability, with heartwood samples ranging from very durable to non-durable. The tannins also bleed brown stains onto adjacent surfaces, so it is a poor choice for shaded or polluted elevations.
Typical applications & suitability
Indoor Outdoor — A genuine exterior hardwood at modest weight — the standard British and southern-European alternative to oak for untreated cladding — and equally at home indoors.
Documented end-uses: external cladding and decking, fencing, posts and utility poles (30–40 year service is typical), furniture and garden furniture, flooring, interior trim and joinery, cooperage and tannin extraction, carving and tool handles.
Comparable species
Species closest to Sweet Chestnut by density, hardness, stiffness and bending strength, computed directly from the Vriksai species dataset rather than hand-picked.
Trade alternatives. Its obvious counterpart is European Oak — similar durability and colour, but heavier and harder to work — while Accoya and ThermoWood Oak offer modified-timber routes to the same untreated-exterior brief.
Alternatives to Sweet Chestnut
Sweet Chestnut measures 680 lbf Janka at 0.56 g/cm³, EN 350 durability Class 2, movement rated Excellent. Because Sweet Chestnut is exterior-rated at Class 2, every candidate below is too. A substitute that quietly drops a durability class is the expensive kind of mistake. Read the numbers against the Janka scale and EN 350 durability classes.
For exterior joinery, cladding and garden work that also has to resist knocks. Harder means more dent resistance but heavier sections and more machining time.
Easier to work and lighter to fix, without dropping below the exterior durability you already have.
Cladding boards and exterior joinery live or die on movement. These give you less of it at equal or better durability. Size the gaps with the shrinkage predictor and EMC calculator.
If Sweet Chestnut is unavailable and the specification cannot change, these are the nearest substitutes across hardness, density, movement, stiffness, bending strength and durability class together — not on any single property. Lower distance means a closer match.
Computed from measured properties only — hardness, density, movement, stiffness, bending strength and EN 350 class. Price, availability and appearance are never inputs. Figures are representative values, not consignment absolutes: two species within a few percent are equivalent until verified on the material. Full method and the rules the engine cannot break.
Substituting outdoors is a match on durability class and movement first. Colour and grain can be matched later; a wrong durability class shows up as a callback in three monsoons. Where two candidates are close, compare them directly before specifying.
Compare Sweet Chestnut side by side
These are the head-to-heads that decide cladding, decking and exterior joinery specifications. Every pairing shows the measured figures side by side; full matrix in the comparison index.
Calculators relevant to Sweet Chestnut
Aimed at exterior detailing in Sweet Chestnut: coverage, gaps, coating and durability checks. Full set in the tool index.
Understand the figures
Moisture content — EMC, FSP and service conditions · Strength properties — MOR, MOE and what they govern · Durability & fire — EN 350 classes and E84 ratings · Thermal conductivity — k-value and insulation behaviour.
Further reading. What is ThermoWood? · Wood moisture content explained · How to calculate board feet.
Common questions about Sweet Chestnut
unverified no published source for this figure · WD The Wood Database (Eric Meier) · calc derived from the figures above · — no published source found