Stevens

SPRUCE - Whitewood

The photographs of the wood species are solely illustrative and may differ from reality.

General

  • Spruce should not be confused with pine, both indigenous and imported
  • Whitish to cream-coloured heartwood and sapwood
  • Non-durable wood, but stable and elastic
  • Used for interior applications such as door frames, floors and furniture
  • Light and strong and therefore highly suitable for structures and even aircraft building
  • Suitable for a great many diverse uses: from electricity poles and masts through construction wood (trusses, structures, etc.), to shuttering
  • Raw material for plywood and paper

Origin

Spruce is the commercial name for the botanical species Picea abies or Picea excelsa, which belong to the Pinaceae family. Belgium markets both indigenous spruce and spruce imported from Sweden, Finland, Norway, Russia, Poland, the Czech Republic and the Baltic States.

In everyday language, spruce is often confused with pine (Pinus sylvestris). This error is encouraged by the commonly used name Abies as with the fir family. And by the name White Northern Pine, under which Sweden, Finland and Russia export spruce. In the Jura area, the spruce is known as faux sapin (false pine) and in the Vosges as gentil sapin (kind pine).


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Quality

Spruce can be graded according to quality in two ways:

  • Grading according to appearance:
    • Imported sawn timber is graded by appearance. Depending on the origin, different grading regulations apply.

    Spruce from Sweden and Finland

    Belgium respects the ‘Nordic timber: grading rules for sawn pine and spruce’, also known as the ‘Scandinavian green book’. This distinguishes six quality classes (from I to VI). ‘Unsorted’ timber includes classes I, II, III and IV. Sweden and Finland also use the ‘Sawfalling’ quality indication. This consists partly of ‘Unsorted’ timber, partly Class V sawn timber and up to 20% as a limited proportion of Class VI sawn timber.

    Spruce from Russia

    The Russians distinguish between five quality classes. ‘Unsorted’ wood includes classes I, II, and III. Their fourth class corresponds with the saw-falling quality of the Scandinavian countries and their fifth with the sixth quality of the Scandinavian countries.

    Spruce from the Baltic States, Poland and the Czech Republic

    The Baltic States, Poland and the Czech Republic export a Sawfalling quality that corresponds closely with that from the Scandinavian countries.

  • Visual grading for construction wood:
    • Belgium applies STS 04. This method makes a link between the number of knots on the cross-section (KAR, Knot Area Ratio) and the mechanical characteristics of the wood. It distinguishes four classes: S4, S6, S8 and S10. As of 1 September 2009, NBN EN 14081 is the reference for CE marking for construction wood.

Colour and figures

Spruce is very light in colour, whitish to cream-coloured. In spruces from mountainous areas, the wood is glossy and sometimes even pearly. Heartwood and sapwood are indistinguishable, although the round, homogeneously wide growth rings are clear. Where the bands are coloured red, that indicates the presence of reaction wood.
The texture is fine in slow-growing wood from the North or from mountainous area and coarser in fast-growing wood from the planes. Spruce has a very straight grain.
On the quarter sawn surface, the small rays give a light, inconspicuous figure.

Durability

Spruce is not durable and is sensitive to blue mould, decay, wood rot and damage by insects, particularly the long-horned beetle. The wood structure doesn’t absorb moisture easily, which reduces the risk of fungus damage.

Drying and Moisture Content

Spruce dries quickly and easily. Drying at a temperature higher than 70°C prevents resin excretion. To prevent blue mould and decay, it is advisable to quickly stack freshly sawn wood on stickers.  That facilitates good surface drying.

Wood-working

Spruce is easy to work. It can split if the grain is diagonal or close to knots, however. When sawing, the hardness of the knots can sometimes make splinters fly off. If you steam the knots beforehand, the wood is easier to work.
Despite the sometimes slightly rough surface, spruce is easy to saw. It is also suitable for flat-cut and rotary-cut veneer.

Gluing

Spruce is easy to glue.

Attaching

Spruce splits easily when nailing or screwing.
Use screws with a longer thread and larger diameter.

Finishing

The finishing of spruce is beautiful, if it is sufficiently dried (to a moisture content of less than 15%).
If you want to use spruce for exterior applications, then you need to impregnate the lumber.
For construction wood, the lumber has to be preserved beforehand in accordance with procedure A2.1.

Applications

Spruce is used in various qualities for innumerable applications:

  • Trusses and structures (solid, industrialised or glued laminated)
  • Interior fittings, such as door frames, walls, flooring, frames and roll-down blinds
  • Electricity poles, stakes and struts
  • Sheet material
  • Paper
  • Masts
  • Furniture
  • Shuttering, packaging, pallets
  • Utensils
  • Musical instruments (sounding boards for violins, guitars, pianos and harps)
  • Aircraft building
  • By-products such as bark for heating, sawdust for cat litter
Professional information

Average density*

450 kg/m³ (420 kg/m³ for Belgian spruce)

Radial shrinkage

60 to 30% r.a.h.**

0,8%

 

90 to 60% r.a.h.**

0,9%

Tangential shrinkage

60 to 30% r.a.h.**

1,5%

 

90 to 60% r.a.h..**

2%

Wood-working

60 to 30% r.a.h.**

2,3%

 

90 to 60% r.a.h.**

2,9%

Flexural strength

71 N/mm²

Modulus of the Elasticity

10.000 N/mm²

Compressive strength (parallel with the fibers)

45 N/mm²

Shear strength

6 N/mm²

Hardness – Radial

2650 N

Hardness

1570 N

* at wood moisture content of 15 per cent / ** relative atmospheric humidity

 

Commercial information

Thickness

19/22/25/32/38/50/63/75 mm

Width

75/100/125/150/175/200/225 mm

 

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