Farm Forestry New Zealand

 Laminating Grades

Further information about structural finger-jointing can be found on the NZ Wood website »

Structural laminating grades

#1 structural, Clears

The timber shall be graded to No. 1 structural. In addition to this, no visual defect allowed on both edges, including:

• Knots, holes, voids, bark-inclusion, bark-pockets, resin pockets, pith, decay;
• no more than one check per lineal metre;
• wane or want.

Faces to be free of skip, collapse, want or wane at the thickness specified by the buyer.

Lengths to be greater than 1.5 m.

#1 structural, Feature

The timber shall be graded to No. 1 structural.

Faces to be free of skip, collapse, want or wane at thickness specified by the buyer.

Lengths to be greater than 1.5 m.

Finger-jointed #1 structural

The timber shall be graded to No. 1 structural. In addition to this, no visual defect allowed on both edges, including:

• Knots, holes, voids, bark-inclusion, bark-pockets, resin pockets, pith, decay, checks;
• wane or want.

Faces to be free of skip, collapse, want or wane at thickness specified by the buyer.

Individual shooks to be minimum 300 mm length. Shooks of less than 900 mm shall not comprise more than 25% of the length.

Finger-jointed product lengths to be specified.

Finger-jointed product lengths sold undressed and ready for dressing and laminating must have the target thickness specified by the buyer and be free of skip, collapse, want or wane once dressed to this thickness.

Structural finger jointing is to be undertaken in accordance with AS/NZS 1491. 

Wood shall be in the range of 6-18% moisture. At the time of layup for hardwoods it is desirable that moisture is between 8-10% and for softwoods between 10-14%. 

Collapse, skip, want or wane shall not be present in the dressed, dry sized timber to be laminated.

 

Panel laminating grades

Clear one face

The faces to be glued shall be free of skip, collapse, want or wane at the thickness specified by the buyer.

Lengths shall be as specified and agreed to for the size of the panel(s).

One exposed face shall be free of the following:

• Knots, holes, voids, bark-inclusion, bark-pockets, resin pockets, pith, decay, wane, want, checks and other contrasting feature (i.e feature that is significantly darker than the surrounding wood);
• Skip, including collapse, which will remain as skip in the face of the dressed panel at the specified thickness.

The hidden face opposite to the exposed face shall:

• have no skip to 0.5 m in from each end at the specified length;
• be suitable for producing a panel that once glued meets the following structural requirements for cross section.

Structural requirements for cross section

Knots, holes, voids, bark-inclusion, bark-pockets, resin pockets, pith (pith includes surrounding wood to a radius of 10 mm), decay, wane, skip, sloping grain greater than 1/10 (including sloping grain surrounding spike knots: Sloping grain surrounding spike knots, being a significant weakness causing defect, must be taken into account when determining the cross section of the spike knot.) and other weakness-causing defect:

• Not more than 1/8 of cross section in combination.

Clear two faces

The faces to be glued shall be free of skip, collapse, want or wane at the thickness specified by the buyer.

Lengths shall be as specified and agreed to for the size of the panel(s).

The two opposite faces to be exposed (i.e. those not to be glued) shall be free of the following:

• Knots, holes, voids, bark-inclusion, bark-pockets, resin pockets, pith, decay, wane, want, checks and other contrasting feature (i.e feature that is significantly darker than the surrounding wood);
• Skip, including collapse, which will remain as skip in either of the two faces of the dressed panel at the specified thickness.

Finger-jointed clear one face

One face shall be clear and shall not have the following defect:

• Knots, holes, voids, bark-inclusion, bark-pockets, resin pockets, pith, decay, wane, want, checks;
• Collapse which would remain as skip in the dressed panel.

The faces to be glued shall be free of skip, collapse, want or wane at the thickness specified by the buyer.

Shooks shall be finger-jointed to lengths as specified and agreed to for the size of the panel(s).

Shooks shall be greater than 300 mm in length and finger-jointed to the length specified. Shooks of less than 900 mm shall not comprise more than 25% of the jointed length.

Finger jointing is to be undertaken in accordance with AS/NZS 1491. 

Wood shall be at 10-14% moisture.

Finger-jointed clear two faces

Two faces opposite each other (those not to be glued) shall be clearwood and shall not have the following defect:

• Knots, holes, voids, bark-inclusion, bark-pockets, resin pockets, pith, decay, wane, checks;
• Collapse which will remain as skip in the dressed panel.

The faces to be glued shall be free of skip, collapse, want or wane at the thickness specified by the buyer.

Shooks shall be jointed into lengths as specified and agreed for the size of the panel(s).

Shooks shall be greater than 300 mm in length and finger-jointed to the length specified. Shooks of less than 900 mm shall not comprise more than 25% of the jointed length.

Finger jointing is to be undertaken in accordance with AS/NZS 1491.

Wood shall be at 10-14% moisture.

General and Responsibilities

Timber is to be dressed to the specified thickness immediately prior to laminating to ensure a good glue bond. The vendor must ensure the timber will have a skip-free surface when it is dressed to the specified thickness for laminating. 

At least 95% of the consignment of graded timber shall meet the grade specifications above upon despatch.

Structural timber shall be dry to 18% moisture or below.

For tallying volumes call dimensions shall be used.

Call sizes (mm)	25	40	50	75	100	125	150	200	225	250	300
Actual dressed dry size (mm)	19	35	45	70	90	115	140	180	205	230	280

Once despatched the seller shall not be responsible for any subsequent deterioration of condition of the timber or defects arising from further processing.

Farm Forestry Timbers reserve the right to revise our grading rules without notice. Grade revision 1.1 October 2013.

See Glossary for explanation of terms.

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