Which wood for what
Whether a wood is suitable depends less on the species than on where it is installed. Indoors, hardness, colour and workability count; outdoors, almost only one thing: how long the wood lasts against fungi without protection.
Outdoors, durability decides, not hardness. Beech and hornbeam are among the hardest woods in the range and are still not durable. Oak and sweet chestnut last longest.
The durability classes
The standard EN 350 divides wood into five classes according to its natural resistance to wood-destroying fungi. It applies to the heartwood, without wood preservatives.
- 1very durable
- 2durable
- 3moderately durable
- 4slightly durable
- 5not durable
The species in the range
Sorted by durability, most durable first. Density applies to air-dried wood at 12 to 15 % wood moisture.
| Wood species | Class | Density | Typical use |
|---|---|---|---|
| Oak | 2 | 670–710 | Furniture, parquet, stairs, cladding, structural use outdoors, cooperage |
| Sweet chestnut | 2 | 540–590 | Furniture, stairs, parquet, structural timber outdoors, vine stakes, cooperage |
| Walnut | 3 | 620–660 | Furniture and panel veneer, turned work, restoration of antique furniture |
| Pine | 3–4 | 490–520 | Walls and ceilings, floors, stairs, facades, windows, doors, fences |
| Larch | 3–4 | 550–590 | Structural timber indoors and outdoors, garden and landscaping, facades, windows, floors |
| Spruce | 4 | 430–470 | Building and bridge construction, floors, stairs, cladding, facades, windows, fences |
| Fir | 4 | 410–450 | Engineered structures, interior fit-out and built-in furniture, facades, windows, doors. No resin canals |
| Cherry | 4 | 560–600 | Interior fit-out: furniture, parquet, cladding, turned goods. Darkens in light |
| Beech | 5 | 680–720 | Furniture, doors, floors, stairs, parquet |
| Hornbeam | 5 | 750–820 | Chopping blocks, tool parts, shoe lasts, piano actions. Exceptionally hard and tough |
| Ash | 5 | 650–690 | Floors, stairs, furniture, tool handles, sports equipment, ladders. Hard and elastic |
| Maple | 5 | 620–660 | Indoors only: furniture, floors, stairs, veneer, musical instruments, turning |
| Lime | 5 | 490–530 | Sculpture and carving, also furniture, toys, plywood |
| Poplar | 5 | 400–450 | Veneer and plywood, packaging, wood-based panels, sauna construction |
Density in kilograms per cubic metre, class to EN 350 for the heartwood. For oak the source gives 2 to 4: pedunculate and sessile oak are durable, red oak only moderately.
Oak, larch, walnut and iron
In these three species, substances in the wood react with iron. In damp conditions, blue-black to blue-grey discolouration occurs, and with oak the fasteners can also corrode.
Sources
Holz vom Fach (GD Holz), Holzarten-ABC, Dauerhaftigkeitsklasse nach DIN EN 350, abgerufen 07.10.2026
Holzdichte-Tabelle, Rohdichte bei 12 bis 15 % Holzfeuchte, abgerufen 16.09.2026