Larch — known in French as mélèze and botanically as Larix — is the hardest, densest softwood native to Europe. Unlike most conifers it is deciduous, dropping its needles each autumn, which forces the tree to grow dense, resinous wood year after year. The result is a timber that punches well above its weight class: harder than pine, more durable than spruce, and strikingly beautiful thanks to a rich reddish-brown heartwood that deepens further with age. Whether you are specifying cladding for a mountain chalet, decking for a wet-climate garden, or flooring that needs to stand up to heavy traffic, larch is one of the most rewarding timbers you can choose from a European forest.
This guide covers everything you need to know: where larch grows, how to identify it, its key mechanical and durability properties, how it behaves during drying and machining, and the commercial dimensions in which it is typically supplied.
The genus Larix belongs to the family Pinaceae and comprises around ten recognised species. All grow exclusively in the northern hemisphere — across alpine and boreal zones of Europe, Asia, and North America.
| Species | Origin |
|---|---|
| L. decidua | Alps, Sudeten, Tatra |
| L. kaempferi | Japan / European plantations |
| L. sibirica | Siberia / Manchuria |
| L. occidentalis | Pacific NW North America |
| L. laricina | Canada / NE United States |
In European trade, the vast majority of sawn larch originates from L. decidua and L. kaempferi. Alpine-sourced decidua commands a premium for its exceptionally tight rings and high resin content.
Looking for finished timber garden products? Our Douglas fir outdoor kitchens and hardwood garden furniture are built from similarly robust, weather-tested species — explore them below.
Larch is one of the most visually distinctive European softwoods. The contrast between heartwood and sapwood is sharp and immediately recognisable:
On external applications the heartwood weathers to a dignified silver-grey if left unfinished — a characteristic widely exploited in Scandinavian and Alpine vernacular architecture.
| Characteristic | Larch |
|---|---|
| Typical height | up to 30 m |
| Trunk diameter | up to 1 m |
| Lifespan | 150–200 years |
Its light canopy allows good understorey development, and on steep slopes the deep root system makes it valuable for erosion control and rock-fall mitigation — one reason it is a favoured species in Alpine reforestation programmes.
Larch is the densest softwood indigenous to Europe — a title it earns through slow, high-altitude growth that packs more wood cells into every growth ring. It is classified as medium-weight and medium-hard, sitting comfortably in the gap between the lighter pines and true hardwoods.
| Property | Value |
|---|---|
| Density (above average) | > 750 kg/m³ |
| Durability class — heartwood | Class III (moderately durable) |
| Durability class — sapwood | Class V (not durable) |
The heartwood carries natural resins that inhibit fungal and insect attack. Class III means it will perform reliably in above-ground exterior use (cladding, decking, joinery) for many years without preservative treatment, provided good design practice is followed — e.g. adequate drainage, no end-grain exposure, and controlled moisture cycling. The sapwood (Class V) should be excluded from exterior structural applications or treated appropriately.
If you are working on an outdoor project and want finished garden furniture or maintenance products alongside your timber research, these are among our most popular choices:
Larch dries reasonably well but requires a controlled, relatively slow schedule. Kiln drying at temperatures up to 75 °C is standard practice; rushing the process encourages surface checking and can cause knots to loosen or drop. Once dried, larch retains a distinctive and persistent resinous scent that many users find pleasant but which does need to be managed during finishing.
Both hand and machine tooling give good results. The most important workshop precaution is pre-drilling before nailing or screwing — larch splits readily along the grain if fasteners are driven without a pilot hole. The presence of hard knots and patches of resin can blunt cutting edges faster than is typical for softer species; keep blades sharp and expect to dress them more frequently on resinous stock.
Larch responds well to sanding and takes paint, varnish and oil finishes acceptably, but its resin content means the surface must be thoroughly degreased before any coating is applied — otherwise adhesion will be poor. A light wash with white spirit or a specialist wood cleaner, followed by adequate drying time, is standard preparation. For exterior joinery, a microporous oil or penetrating stain is generally preferred over a film-forming paint, as it accommodates the slight movement that larch exhibits across the seasons.
| Working Property | Assessment |
|---|---|
| Machinability | Good — hand and machine |
| Pre-drilling | Required (splits easily) |
| Knot behaviour | Hard, occasionally loose — check before finishing |
| Resin content | High — degrease before coating |
| Sanding | Good response |
| Gluing | Acceptable after surface preparation |
| Kiln temp (max) | 75 °C |
The values below are representative of commercially dried European larch (Larix decidua and L. kaempferi) at standard equilibrium moisture content. Figures from high-altitude Alpine origin may sit towards the upper end of ranges; plantation-grown material tends towards the lower end.
| Property | Value |
|---|---|
| Average volumetric density | 600 kg/m³ |
| Maximum density | > 750 kg/m³ |
| Radial shrinkage (60–30% RH) | 0.6% |
| Tangential shrinkage (60–30% RH) | 0.9% |
| Volumetric movement (60–30% RH) | 1.5% |
| Bending strength (MOR) | 94 N/mm² |
| Modulus of elasticity (MOE) | 10,600–14,500 N/mm² |
| Compression strength (parallel to grain) | 54 N/mm² |
| Tensile strength (parallel to grain) | 101 N/mm² |
| Shear strength | 9.9 N/mm² |
| Natural durability — heartwood | Class III (moderately durable) |
| Natural durability — sapwood | Class V (not durable) |
A bending strength of 94 N/mm² places larch comfortably ahead of Scots pine (typically around 80 N/mm²) and well within the range used for structural softwood applications. The wide MOE range reflects the significant variation between slow-grown Alpine stock and faster-grown plantation material.
Larch is typically supplied sawn and kiln-dried. The table below shows the principal cross-sections available in the trade; lengths of 180 cm and above are standard on most profiles, with shorter material available on request.
| Thickness × Width | Available Lengths |
|---|---|
| 19 mm × 75 / 100 / 125 / 150 / 175 / 200 / 225 mm | On request, various lengths |
| 25 mm × 100 / 125 / 150 / 175 / 200 / 225 mm | 180 cm and above |
| 32 mm × 100 / 125 / 150 / 175 mm | 180 cm and above |
| 38 mm × 100 / 125 / 150 / 175 / 200 mm | 180 cm and above |
| 50 mm × 100 / 125 / 175 / 200 / 225 mm | 180 cm and above |
| 63 mm × 125 / 150 / 175 / 200 / 225 mm | 180 cm and above |
| 75 mm × 150 / 200 / 225 mm | 180 cm and above |
| 95 mm × 95 mm | 180 cm and above |
| 98 mm × 98 mm | 180 cm and above |
The 95 × 95 mm and 98 × 98 mm square sections are widely used for posts, pergola uprights, and structural framing where a clean, chunky profile is required.
The heartwood is rated Durability Class III (moderately durable), which means it will perform acceptably in above-ground exterior applications — cladding, garden joinery, pergola frames — without preservative treatment, provided it is well designed and well maintained. Good practice means ensuring drainage away from end grain, keeping the wood out of direct ground contact, and applying a UV-stable oil or stain to reduce surface checking. The sapwood (pale yellow-white zones) is Class V and should not be relied upon for exterior exposure.
Both are resinous, relatively dense softwoods with good natural durability. Douglas fir (Pseudotsuga menziesii) is typically slightly lighter in colour and marginally easier to coat, while European larch tends to be denser and higher in resin, which can make it slightly harder to finish but more naturally resistant once the surface is properly prepared. For cladding and decking in the UK climate, both are well-regarded choices; the decision often comes down to availability, grade and aesthetics.
Larch has a tight, straight grain that offers very little lateral give, so driving a fastener without a pilot hole creates a splitting force that can run along the grain and cause the board to crack, particularly near edges or ends. Pre-drilling takes only seconds and completely eliminates the problem. Use a bit marginally smaller than the screw shank and countersink flush or slightly below the surface to prevent water pooling around the fastener head.
It can, particularly on cut ends and around knots, if the surface is not properly prepared. Degrease the timber thoroughly before applying any coating — a wipe-down with white spirit or a dedicated resin-remover solution is standard practice. Follow with a stain-blocking primer if using a film-forming paint. Penetrating oils and microporous stains tend to be less prone to resin bleed-through than conventional paints and are generally the preferred finish for exterior larch.
Larix decidua (European larch) grown at altitude produces the tightest rings, highest density and most resinous timber. Larix kaempferi (Japanese larch), now widely grown in European plantations including the UK, grows faster and produces slightly wider-ringed, moderately less dense timber — but it is more resistant to larch canker disease, which makes it easier to manage forestry-wise. Both yield very usable structural and cladding timber; in most British merchant stock the two are traded interchangeably under the general designation "larch".
Yes — larch decking is a popular choice in the UK and across northern Europe. Its density (average 600 kg/m³, peaks above 750 kg/m³) gives it good resistance to wear and indentation, and the natural resin content provides a degree of moisture resistance. For decking, specify heartwood-rich boards and use concealed clip fixings or pre-drilled screw fixings as described above. An annual application of a UV-protective decking oil will extend service life and preserve the warm reddish-brown colour; left untreated it will silver gracefully.
Larch's durability, warmth and structural strength make it a natural reference point when you are specifying any outdoor timber project. Our range of garden furniture and outdoor structures is built from species chosen with exactly the same criteria in mind — robust, long-lasting hardwoods and durable treated softwoods that are made to live outside.
