Home / Wood Compare / Accoya Acetylated Radiata Pine vs Sweet Chestnut
Professional Comparison · Source-attributed engineering data · Updated 19 July 2026
Accoya Acetylated Radiata Pine VS Sweet Chestnut
Which wood is better for your project? Scores are computed from the verified figures on each species page — how we score.
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Accoya Acetylated Radiata Pine
68/100 Library Score
🌲Softwood🌧Outdoor💧Moisture Stable🌿Sustainable
- Higher durability (EN 350 Class 1 vs Class 2)
- Better dimensional stability (Exceptional vs Excellent)
🥈
Sweet Chestnut
51/100 Library Score
🪵Hardwood🌧Outdoor💧Moisture Stable
- Close second across most categories
- Solid choice where its profile fits the project
Visual comparison
Accoya Acetylated Radiata PineSweet Chestnut
Winner by category
There isn't one universally best wood — there's a best wood for each purpose.
| Category | Winner |
|---|---|
| Durability | Accoya Acetylated Radiata Pine |
| Stability | Accoya Acetylated Radiata Pine |
| Hardness | Tie |
| Strength (MOR) | Sweet Chestnut |
| Stiffness (MOE) | Sweet Chestnut |
| Flame spread | Sweet Chestnut |
| Machining ease | Accoya Acetylated Radiata Pine |
| Lightness | Accoya Acetylated Radiata Pine |
Engineering data
| Property | Accoya Acetylated Radiata Pine | Sweet Chestnut |
|---|---|---|
| Janka Hardness | 710 lbf | 680WD lbf |
| Density | 0.51 g/cm³ | 0.56WD g/cm³ |
| MOE | 8.5 GPa | 8.61WD GPa |
| MOR | 60.0 MPa | 71.4WD MPa |
| Durability | Class 1 Very Durable (treated) | Class 2 Durable |
| Stability | Exceptional | Excellent |
| Fire (E84) | Not classified | Class B indicative |
| Radial Shrink | 0.7 % | 4.2WD % |
| Tangential Shrink | 1.5 % | 6.9WD % |
| T/R Ratio | 2.14 | 1.64 |
Figures carry the same source status as the species pages they come from — verified where cited, indicative where marked.
Best for
| Application | Recommended | Suitability |
|---|---|---|
| Outdoor decking / pergola | 🥇 Accoya Acetylated Radiata Pine | ★★★★★ |
| Exterior cladding | 🥇 Accoya Acetylated Radiata Pine | ★★★★★ |
| Flooring / wear surfaces | 🥇 Accoya Acetylated Radiata Pine | ★★★☆☆ |
| Furniture / interior joinery | 🥇 Accoya Acetylated Radiata Pine | ★★★★☆ |
| Structural / load-bearing | 🥇 Sweet Chestnut | ★☆☆☆☆ |
| Sauna / wet interiors | 🥇 Accoya Acetylated Radiata Pine | ★★★★★ |
Advantages & limitations
Accoya Acetylated Radiata Pine
Advantages relative to Sweet Chestnut
- Durability is Class 1 vs Class 2 — one class more durable in exterior and ground-contact service
Limitations relative to Sweet Chestnut
- MOR is 60 MPa vs 71.4 MPa, about 16% lower
- Fire (E84) is Not classified vs Class B — no rated flame-spread classification
Sweet Chestnut
Advantages relative to Accoya Acetylated Radiata Pine
- MOR is 71.4 MPa vs 60 MPa, about 19% higher
- Fire (E84) is Class B vs Not classified — a rated flame-spread classification
Limitations relative to Accoya Acetylated Radiata Pine
- Durability is Class 2 vs Class 1 — one class less durable in exterior and ground-contact service
Recommendation
Choose Accoya Acetylated Radiata Pine if…
- Exterior windows and doors (the timber's flagship application), wide-board cladding and rainscreens up to 200 mm wide, and civil-works applications where Class 1 durability from acetylation is what the project needs
- Bridges and shou-sugi-ban charred cladding where the modified dimensional stability and durability class are the specification
Choose Sweet Chestnut if…
- External cladding, decking and fencing where the higher bending strength and the Class B fire classification matter in specification
- Posts and utility poles (30-40 year documented service), interior joinery and cooperage where the natural durability rating (Class 2) is acceptable for the exposure
Frequently asked questions
Which is more durable, Accoya Acetylated Radiata Pine or Sweet Chestnut?
Accoya Acetylated Radiata Pine — it carries the better EN 350 rating (Class 1 vs Class 2). Lower class numbers mean higher natural durability.
Which wood is better for outdoor use?
Accoya Acetylated Radiata Pine — outdoor performance combines decay durability with dimensional stability, and it leads on that combination.
Is Accoya Acetylated Radiata Pine harder than Sweet Chestnut?
Yes — Janka 710 lbf vs 680 lbf.
How we score. Both Library Scores above are percentile ranks inside our 60-species library, from a weighted composite led by durability (22%) and dimensional stability (18%). Price is deliberately not scored. Full weighting and what it excludes.