Natural durability class (EN 350) and indicative fire performance (ASTM E84 flame-spread class) for 60 timber species. The two factors that decide whether a wood survives outdoors and how it behaves in fire.
Natural durability (EN 350) grades heartwood resistance to decay fungi from Class 1 (Very Durable, 25+ years in ground contact) to Class 5 (Not Durable, under 5 years). Teak, ipe and the rosewoods are Class 1; pale temperate woods like beech, ash and birch are Class 5 and need treatment outdoors. Sapwood of every species is treated as Class 5. Fire class shown is an indication from the ASTM E84 flame-spread scale — Class A (best, flame-spread index 0–25), B (26–75), C (76–200). Dense, oily woods such as ipe genuinely test at Class A; most timber falls in B–C.
| Species ↕ | Durability Class ↕ | Rating ↕ | Ground Life ↕ | Fire (E84) ↕ | Specific Gravity ↕ |
|---|---|---|---|---|---|
| Lignum VitaeGuaiacum officinale | Class 1 | Very Durable | 25+ yrs | Class A | 1.05 |
| African BlackwoodDalbergia melanoxylon | Class 1 | Very Durable | 25+ yrs | Class A | 0.98 |
| Ipe LapachoHandroanthus serratifolius | Class 1 | Very Durable | 25+ yrs | Class A | 0.92 |
| EbonyDiospyros ebenum | Class 1 | Very Durable | 25+ yrs | Class A | 0.90 |
| CumaruDipteryx odorata | Class 1 | Very Durable | 25+ yrs | Class A | 0.87 |
| MassarandubaManilkara bidentata | Class 1 | Very Durable | 25+ yrs | Class A | 0.85 |
| JarrahEucalyptus marginata | Class 1 | Very Durable | 25+ yrs | Class B | 0.82 |
| WengeMillettia laurentii | Class 1 | Very Durable | 25+ yrs | Class B | 0.80 |
| Indian RosewoodDalbergia latifolia | Class 1 | Very Durable | 25+ yrs | Class B | 0.75 |
| MerbauIntsia bijuga | Class 1 | Very Durable | 25+ yrs | Class B | 0.74 |
| Thermowood Oak ThermoDQuercus robur | Class 1 | Very Durable (treated) | 25+ yrs | Class C | 0.68 |
| Burma Teak Premium GradeTectona grandis | Class 1 | Very Durable | 25+ yrs | Class B | 0.66 |
| TeakTectona grandis | Class 1 | Very Durable | 25+ yrs | Class B | 0.55 |
| IrokoMilicia excelsa | Class 1 | Very Durable | 25+ yrs | Class B | 0.55 |
| Accoya Acetylated Radiata PinePinus radiata | Class 1 | Very Durable (treated) | 25+ yrs | Class C | 0.51 |
| BangkiraiShorea laevis | Class 2 | Durable | 15-25 yrs | Class A | 0.85 |
| Spotted GumCorymbia citriodora | Class 2 | Durable | 15-25 yrs | Class B | 0.85 |
| BalauShorea spp. | Class 2 | Durable | 15-25 yrs | Class B | 0.78 |
| Shisham SissooDalbergia sissoo | Class 2 | Durable | 15-25 yrs | Class B | 0.75 |
| SalShorea robusta | Class 2 | Durable | 15-25 yrs | Class B | 0.74 |
| GarapaApuleia leiocarpa | Class 2 | Durable | 15-25 yrs | Class B | 0.72 |
| NeemAzadirachta indica | Class 2 | Durable | 15-25 yrs | Class C | 0.68 |
| European OakQuercus robur | Class 2 | Durable | 15-25 yrs | Class B | 0.67 |
| Thermowood Ash ThermoDFraxinus excelsior | Class 2 | Durable (treated) | 15-25 yrs | Class C | 0.66 |
| Thermowood Birch ThermoDBetula pubescens | Class 2 | Durable (treated) | 15-25 yrs | Class C | 0.62 |
| Thermowood Siberian Larch ThermoDLarix sibirica | Class 2 | Durable (treated) | 15-25 yrs | Class C | 0.59 |
| Sweet ChestnutCastanea sativa | Class 2 | Durable | 15-25 yrs | Class B | 0.56 |
| Thermowood Larch ThermoDLarix decidua | Class 2 | Durable (treated) | 15-25 yrs | Class C | 0.55 |
| Thermowood Radiata Pine ThermoDPinus radiata | Class 2 | Durable (treated) | 15-25 yrs | Class C | 0.50 |
| Deodar CedarCedrus deodara | Class 2 | Durable | 15-25 yrs | Class C | 0.48 |
| Thermowood Pine ThermoDPinus sylvestris | Class 2 | Durable (treated) | 15-25 yrs | Class C | 0.48 |
| Thermowood Spruce ThermoDPicea abies | Class 2 | Durable (treated) | 15-25 yrs | Class C | 0.45 |
| Hinoki CypressChamaecyparis obtusa | Class 2 | Durable | 15-25 yrs | Class C | 0.42 |
| Thermowood Western Red Cedar ThermoDThuja plicata | Class 2 | Durable (treated) | 15-25 yrs | Class C | 0.38 |
| Western Red CedarThuja plicata | Class 2 | Durable | 15-25 yrs | Class C | 0.32 |
| KeruingDipterocarpus spp. | Class 3 | Moderately Durable | 10-15 yrs | Class C | 0.69 |
| SapeleEntandrophragma cylindricum | Class 3 | Moderately Durable | 10-15 yrs | Class B | 0.62 |
| Black WalnutJuglans nigra | Class 3 | Moderately Durable | 10-15 yrs | Class B | 0.55 |
| European LarchLarix decidua | Class 3 | Moderately Durable | 10-15 yrs | Class C | 0.55 |
| Meranti Red LauanShorea spp. | Class 3 | Moderately Durable | 10-15 yrs | Class C | 0.52 |
| African MahoganyKhaya ivorensis | Class 3 | Moderately Durable | 10-15 yrs | Class B | 0.52 |
| American CherryPrunus serotina | Class 3 | Moderately Durable | 10-15 yrs | Class B | 0.50 |
| Douglas FirPseudotsuga menziesii | Class 3 | Moderately Durable | 10-15 yrs | Class C | 0.48 |
| Sugi Japanese CedarCryptomeria japonica | Class 3 | Moderately Durable | 10-15 yrs | Class C | 0.38 |
| Bamboo Structural EngineeredBambusa / Dendrocalamus spp. | Class 4 | Slightly Durable | 5-10 yrs | Class C | 0.60 |
| Southern Yellow PinePinus spp. (P. palustris, P. taeda) | Class 4 | Slightly Durable | 5-10 yrs | Class C | 0.51 |
| Scots PinePinus sylvestris | Class 4 | Slightly Durable | 5-10 yrs | Class C | 0.49 |
| Kail Blue PinePinus wallichiana | Class 4 | Slightly Durable | 5-10 yrs | Class C | 0.45 |
| Hem-FirTsuga / Abies spp. | Class 4 | Slightly Durable | 5-10 yrs | Class C | 0.45 |
| Western HemlockTsuga heterophylla | Class 4 | Slightly Durable | 5-10 yrs | Class C | 0.45 |
| Norway SprucePicea abies | Class 4 | Slightly Durable | 5-10 yrs | Class C | 0.43 |
| Spruce-Pine-Fir SPFPicea / Pinus / Abies spp. | Class 4 | Slightly Durable | 5-10 yrs | Class C | 0.42 |
| PaulowniaPaulownia tomentosa | Class 4 | Slightly Durable | 5-10 yrs | Class C | 0.28 |
| European BeechFagus sylvatica | Class 5 | Not Durable | <5 yrs | Class B | 0.68 |
| Hard MapleAcer saccharum | Class 5 | Not Durable | <5 yrs | Class B | 0.63 |
| Yellow BirchBetula alleghaniensis | Class 5 | Not Durable | <5 yrs | Class B | 0.62 |
| Silver BirchBetula pendula | Class 5 | Not Durable | <5 yrs | Class B | 0.61 |
| White AshFraxinus americana | Class 5 | Not Durable | <5 yrs | Class B | 0.60 |
| Rubber WoodHevea brasiliensis | Class 5 | Not Durable | <5 yrs | Class C | 0.55 |
| Mango WoodMangifera indica | Class 5 | Not Durable | <5 yrs | Class C | 0.51 |
