What is Douglas fir? Properties, uses and durability
The Wood Guide · The wood register
Softwood · from our workshopDouglas fir
There are woods you use, and woods you feel. Douglas fir belongs to the second kind: strength, character and outdoor durability in one material.
- Pseudotsuga menziesii
- Durability class 3 · 10–15 years
- Weathers to an even silver grey
Douglas firPseudotsuga menziesii
Douglas fir at a glance
Not the hardest, not the softest — but one of the most complete softwoods you can choose. Stronger than spruce, cheaper than oak, more stable than larch.
What makes Douglas fir special is its strength-to-weight ratio. It is lighter than hardwood but performs close to it — which is why you see it in large spans: carports, pergolas, verandas. And it is one of the few softwoods that you can leave untreated outdoors in our climate without having to replace it after three years.
Our Douglas fir garden benches, garden sets, outdoor kitchens and planters. All from heartwood — the part of the trunk that actually lives up to that class 3.
- Botanical
- Pseudotsuga menziesii (Douglas fir)
- Heartwood
- orange to rust brown, sometimes pinkish
- Density
- 470–550 kg/m³ (at 12% moisture)
- Hardness
- 2,760–3,100 N (Janka)
- Outdoors
- class 3 — 10–15 years, often 20+
- Maintenance
- virtually none, unless you want to keep the colour
- Price range
- mid-range
To be fair: in warm weather resin can bead out of a knot — "bleeding", as the trade calls it. Wipe it off and you're done, but you should know.
Up to more than 100 metres tall
In the wild, Douglas fir grows in western North America, from British Columbia to northern California: 70 to more than 100 metres tall, some specimens 500 to 1,000 years old. In 1827 David Douglas sent the first seeds to Europe; from 1850 Douglas fir was planted on a large scale in Belgium, the Netherlands, France and Germany.
Click a chapter or use the arrows · tree, growth rings and greying schematic, time speeded up.
From wild giant to European classic
Douglas fir is not a true fir, not a pine and not a larch — it forms a genus of its own.
In the wild it grows in western North America, from British Columbia to northern California. There it reaches 70 to more than 100 metres, with dead-straight trunks, and some specimens live 500 to 1,000 years.
In 1827 the Scottish botanist David Douglas — after whom the tree is named — sent the first seeds to Europe. What began as a curiosity in English estate woodlands grew into one of the continent's most important softwoods. From 1850 onwards Douglas fir was planted on a large scale in Belgium, the Netherlands, France and Germany.
Thanks to the temperate climate and longer growing seasons you get finer growth rings, more even wood and fewer resin pockets than with American Douglas fir. It is slightly lighter but keeps all its strength. What's more, more and more Douglas fir comes from local forests — a shorter chain, a smaller footprint.
Appearance, scent and greying
Douglas fir has a face you don't soon forget — and it changes over the years.
Colour with contrast
Warm orange-reddish brown to rust-brown heartwood, sometimes with a hint of pink or amber. The sapwood is lighter: yellowish white to light brown. You often see both in boards — that contrast gives character.
Grain and growth rings
Straight to slightly wavy, with clear, regular rings. European Douglas fir usually has 3 to 6 per centimetre. The closer the rings, the slower the growth and the harder the wood.
Resin and scent
Natural resin canals contribute to its durability. Small resin pockets or streaks are not a defect but a sign of authenticity — and freshly sawn, Douglas fir smells slightly sweet and resinous.
Greying: its second life
Leave Douglas fir untreated outdoors and it starts to change colour after three to six months. UV radiation breaks down the lignin and the wood takes on a silver-grey patina. After one to two years the change is complete.
Many people find the grey more beautiful: calmer, more neutral, more timeless. It suits clean-lined architecture and country romance alike. And every board greys slightly differently — depending on orientation, sun and rain — so you get subtle variation instead of monotony.
Technical properties
With what each value means in practice — figures without explanation say nothing.
| Property | Value | What that means in practice |
|---|---|---|
| Density (12% moisture) | 470–550 kg/m³ | Lighter than oak, heavier than spruce: easy to work and sturdy enough for construction |
| Durability class heartwood | Class 3 (EN 350) | Untreated above ground 10–15 years; with good ventilation and drainage often 20 years or more |
| Strength class | C24 to C30 (EN 338) | Excellent for load-bearing structures: beams, rafters, frames, floors |
| Hardness (Janka) | 2,760–3,100 N | Harder than larch and clearly harder than spruce — resists wear well |
| Bending strength | 78–92 N/mm² | Deflects less readily than other softwoods; ideal for spans and decking |
| Compressive strength parallel to grain | 40–50 N/mm² | Holds up well under vertical load: columns, uprights, posts |
| Volumetric shrinkage | 11–13% | Moderate shrinkage; very stable once dried to 12–15% moisture |
| Modulus of elasticity | 11,000–13,000 N/mm² | Stiff enough for floors and stairs without a springy feel |
Douglas fir next to other species
| Property | Douglas fir | Larch | Spruce | Oak |
|---|---|---|---|---|
| Outdoor durability | Class 3 (10–15 years) | Class 3–4 (8–12 years) | Class 4 (5–8 years) | Class 2 (15–25 years) |
| Strength class | C24–C30 | C18–C24 | C16–C24 | D40–D50 |
| Density | 470–550 kg/m³ | 550–590 kg/m³ | 430–470 kg/m³ | 650–720 kg/m³ |
| Greying | Even silver grey | Grey with brown patches | Uneven grey | Silver grey |
| Workability | Excellent | Good | Very good | Good, but heavy |
Read also Douglas fir or hardwood, or larch or Douglas fir for the detailed comparison.
Where Douglas fir shines
Indoors and outdoors, with a practical point of attention for each use.
Decking and boardwalks
Wide boards that feel warm underfoot. Choose at least 28 mm thickness; fixing from underneath gives a neater finish.
Garden furniture
From sturdy tables to elegant benches. Douglas fir keeps its shape, weathers beautifully and asks little. Browse the Douglas fir range.
Cladding
Vertical or horizontal boards that grey beautifully. Use heartwood and provide at least a 20 mm ventilation cavity behind it.
Pergolas and carports
Beams of 70×170 or 90×190 mm for large spans; strength class C24 allows 4 to 6 metres.
Fences and gates
Battens, boards or posts. Use class 3 heartwood and always keep posts out of ground contact, on concrete footings or metal post anchors.
Play equipment
Safe, low in splinters and weather-resistant. Rounded corners and a smooth finish make it child-friendly.
Floors and stairs
Warm, sturdy boards. Use well-dried wood (12–15% moisture) and finish with hardwax oil or UV lacquer.
Wall cladding and beams
Vertical boards make a room look taller, horizontal ones wider. Exposed beams give a country or industrial feel.
What Douglas fir is not good for
- Direct ground contact. Class 3 is not suitable for permanent contact with damp soil. Use class 1–2 wood, or put Douglas fir on concrete footings and steel anchors.
- Permanently under water. For sheet piling and quay walls you choose azobé or steel.
- High-precision cabinetmaking. For veneer or instrument making, evenly grown hardwoods are more stable. Douglas fir is strong, not fine.
Douglas fir in the garden
From complete garden sets to outdoor kitchens and planters — all in European Douglas fir heartwood.
Outdoor kitchens in Douglas fir
Douglas fir works well with composite worktops or stainless steel appliances, and ages elegantly without giving way. See also the flower and plant boxes.
How Douglas fir stays beautiful — or becomes more beautiful
You have the choice: keep the warm colour, or let it grey. Both are fine. It depends on your taste and the time you want to spend on it.
Let it grey naturally
- UV light breaks down the lignin; after one to two years the silver grey is complete.
- Maintenance: rinse once a year with water and a soft brush.
- Advantage: virtually maintenance-free, timeless look.
- Drawback: some people find grey less warm than the original reddish brown.
Keep the warm colour
- Treat with wood oil or a transparent stain with a UV filter.
- Once a year; for the first treatment two coats with drying in between.
- Do it in spring or early summer, in dry weather between 10 and 25 °C.
- Drawback: it needs attention every year.
Solving problems
Green algae
Normal on weathered wood. Brush off with water and a soft brush, or use a biodegradable algae remover.
Black spots
Mould caused by poor ventilation. Remove with a vinegar solution (one part vinegar to one part water), let it soak in and rinse off — and improve the ventilation behind or under the wood.
Resin bleed
Can occur on fresh wood. Remove with white spirit, let it dry and then treat with oil.
Frequently asked questions about Douglas fir
How long does Douglas fir last outdoors?
The heartwood reaches durability class 3: untreated and above ground usually 10 to 15 years. With good construction details — ventilation and drainage — often twenty years or more.
Do I need to treat Douglas fir?
Not if you let it grey; rinsing once a year is then enough. If you want to keep the warm reddish-brown colour, treat it every year with wood oil or a transparent stain with a UV filter.
Why does Douglas fir grey so evenly?
UV light breaks down the lignin in the wood. Douglas fir does this more evenly than larch or spruce, so you get an even silver grey instead of patches. After one to two years the change is complete.
Can Douglas fir go in the ground?
No. Class 3 is not suitable for permanent contact with damp soil. Put posts on concrete footings or steel anchors, or choose a species in class 1 or 2.
Is European Douglas fir better than American?
For our uses, usually yes. The temperate climate and longer growing seasons give finer growth rings, more even wood and fewer resin pockets. It also comes from a shorter chain.
What is the difference with hardwood?
Hardwood is denser, heavier and naturally more durable; Douglas fir is lighter, cheaper and easier to work. The full trade-off is in Douglas fir or hardwood.
Compare Douglas fir
Douglas fir is one of the twelve species in our register — and often the smart middle way.
Have a question about your project? Just ask — we're happy to help.
Pseudotsuga menziesii — Lumbar, Public domain · Pseudotsuga menziesii — Jean-Pierre Chéreau & Roger Culos, CC BY-SA 3.0 · Photo via Wikimedia Commons: Pseudotsuga menziesii — Joe Mabel, CC BY-SA 4.0