Fir

Fir

Abies alba
Other names: Silver fir, Sapin

General description

Fir is a typical tree growing in the shadows of higher trees. It is distributed over the whole of Europe, has a straight trunk and grows to a height of about 40 m

Wood description

The colour is white with a little tendency to grey-violette. Heartwood is not distinct from sapwood. The texture is fine to medium according to growing speed. There is no resin in the wood. The wood is similar to spruce: soft, low in weight and has medium density. Strength properties are good.
Sawing and machining is easy, also assembling. Fir also has a slight tendency to split when nailed.

Common uses

Fir and Spruce wood are often mixed for structural end uses, indoors and outdoors: general carpentry, interior construction, windows and doors.

Physical characteristics
Density (at 12 % moisture content) 441 kg⁄m3
Total longitudinal shrinkage 0.1 – 02 %
Total radial shrinkage 3.8 %
Total tangential shrinkage 7.6 %
Equilibrium moisture content  
(20° C⁄ 37 % rel. humidity) 7.1 %
(20° C⁄ 83 % rel. humidity) 16.9 %
Mechanical characteristics
Modulus of elasticity under bending 11000 N⁄mm2
Modulus of rupture under bending 73 N⁄mm2
Tension strength 84 N⁄mm2
Compression strength 45 N⁄mm2
Brinell hardness perpendicular to the fibres 14 N⁄mm2
Janka Hardness 1.8 kN
Nail withdrawal strength in N per mm depth and mm diameter 5.0 N⁄mm2
Natural durability and treatability (according to en 350-2)
Fungi Class 4 –poorly durable
Dry wood borers susceptible
Termites Class S susceptible
Treatability 2 – 3 poorly to moderately permeable

Natural durability is based on mature heartwood. Sapwood must always be considered as non durable against wood destroying agents.