Douglas fir - not just for the patio


Douglas fir wood is not only a popular type of wood for terraced construction, but also an important timber, which is also approved for roof trusses and other load-bearing constructions. What else Douglas fir wood can be used for, and what special qualities it has, can be found here.

Other names and DIN names

Other names for the Douglas fir are also Douglas fir or Douglas spruce as well as Douglas Kiefer, in the American range also Oregon Fir or Oregon Pine. Many of the alternative names are botanically incorrect, as the Douglas fir is actually one of the pine family.

usedesignation
National designation according to DINDouglas
Abbreviation according to DINDG, also DGA (American Douglas fir)
International designations and abbreviations according to DIN EN 13 556Douglas Fir (PSMN, EU), American Douglas Fir (PSMN, AM)

Appearance

The Douglas fir is a heartwood tree, which means that the heartwood has a different color from sapwood. In addition, the heartwood can darken significantly over time.

Grain

The Douglas fir has a non-porous wood, the structure looks very streaky (similar to the larch). On the basis of the structure one can distinguish well Yellow Fir (brighter, finer drawn) and the coarser drawn Red Fir (also in color usually darker). You can see resin channels in the wood.

colour

The heartwood of the Douglas fir is pale yellow to slightly brownish, but may also be marked reddish brown. The sapwood, however, is usually very light, almost white to yellowish gray. The heartwood darkens significantly over time.

properties

General properties

Douglas fir wood has a high strength, but it is still soft and coarse-grained. It is especially tough and durable. Douglas fir wood is easily fissile. The strength properties vary somewhat with the locations, European Douglas fir woods are usually slightly less solid than American woods.

Shrinkage and drying

The shrinkage behavior of Douglas fir wood is only moderate. The drying process is usually unproblematic, with larger dimensions, however, occasionally carelessly drying on the wood surface can form very fine cracks. Douglas fir is dimensionally stable during drying.

resistance

The consistency of Douglas fir wood is relatively good, but can not compete with highly resistant woods such as the robinia or even teak wood. Douglas fir wood is moderately resistant to fungal infestation, the risk is at least low. Douglas fir wood is basically weatherproof. The life is not as high as with more stable woods (such as acacia wood). In the outdoor area, protection for Douglas fir (impregnation, glazing) is always recommended despite the resistance.

particularities

resin outlet

Resin can also escape from the finished wood. This is often perceived as disturbing, but it is one of the characteristics of the wood. The culprits are the Harzkanälchen, which remain in the wood and secrete a very aromatic smelling resin, especially when the wood is heated.

discoloration

Discoloration can occur very easily in Douglas fir. They are mainly produced in damp wood in contact with ferrous metals. The blackish-bluish discoloration is often confused with a blueness, but is based purely on a chemical reaction of the wood components with the metal.

use

For Douglas fir there are many uses. On the one hand, it is a timber approved for load-bearing constructions and has better properties than spruce wood, which is common, for example, for roof trusses. It is also used in interior design, such as for parquet or furniture, as well as for wooden windows. It is also used for terraces and garden furniture, but always requires additional protection.

Traditional use

Traditionally, the use in shipbuilding - for masts, even earlier, often for other parts in boat building.

ancestry

Douglas fir wood can come either from Europe or from America. This also influences somewhat the properties of the wood.

Technical values

Reading Descriptionvalue
density0.35-0.77 g / cc
Medium volume density445 kg / m³
Compressive strength46 - 53 N / mm²
flexural strength80 - 99 N / mm²
condensing4.4 kWh per kg but only 1.700 kWh per room meter - for comparison: oak and beech: 2,100 kWh

Prices)

As Oregon Pine you have to expect about 1300 - 1.800 EUR per m³ for lumber, as a construction timber of European origin can be expected in about a price of 900 - 1.100 EUR per m³.

All types of wood at a glance

Tips & Tricks

Occasionally you use the Douglas fir because of its durability and the beautiful look as a Christmas tree. With heavy Christmas tree ornaments but you should use it more sparingly.


Video Board: Durable Outdoor Finish