Farm Forestry New Zealand

 Flooring Grades

All grades:

The end use (overlay or flooring over joists) and grade (e.g. Clears, Standard, Natural Feature grade) shall be specified.

Distortion:

• Bow maximum 40/1;
• Crook maximum 200/1;
• Twist minimal;
• Cup 75/1 rough sawn.

No visible wane or skip allowed on the top surface of the profiled product. Collapse allowed on bottom profiled surface provided this does not interfere with the fixing and stability of the floor in service.

Splits not allowed. Shakes not allowed.

Decay not allowed.

Sap stain not allowed.

The timber shall be dried to between 8 and 12 % moisture. Moisture level shall be specified and must be within two percent either side of the specified moisture content. Where a higher moisture level is required and specified, this shall not exceed 16%.

Species

Cypress (macrocarpa, lusitanica, Lawsons, Leyland)

Eucalyptus

Blackwood

Beech (red, silver, black, hard), Tawa, Rimu, Matai, Totara and other native species.

For overlay flooring:

Lengths must be greater than 600 mm. Lengths longer than 1.2 m must comprise more than 75% of the consignment.

Where wane or skip is present on the tongue or groove on the bottom surface, this shall not exceed the full width of the tongue or groove.

Profiled thickness shall be 12 mm or greater.

For flooring over joists (strip flooring):

Lengths must be greater than 900 mm. Lengths longer than 1.2 m must comprise more than 75% of the consignment.

Where wane or skip is present on the tongue or groove on the bottom surface, this shall not exceed half the full width of the tongue or groove.

Profiled thickness shall be 19 mm or greater.

Structural requirements
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 that exceeds 1 in 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 1/3 of cross section in combination up to 150 mm board;
• Not more than 1/4 of cross section in combination for larger than 150 mm board.

No voids ("Voids" include holes, bark-pockets, resin pockets and bark inclusion) longer than the width of the face of the piece. Where bark inclusion and associated voids do not exceed 5% of the cross section the length is not restricted. Checks not restricted.

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Clears grade

Best (top) surface:

• No tight knots with diameter exceeding 15 mm.
• No bark inclusion or partially intergrown knots. No loose knots, holes, voids, bark-pockets, resin pockets, kino, pith, discoloured wood or incipient decay.
• No knot checks.
• No checks.
• No contrasting feature, i.e. feature that is significantly darker than the surrounding wood.

Standard grade

Best (top) surface:

• No bark inclusion or partially intergrown knots. No loose knots, holes, voids, bark-pockets, resin pockets, kino, or pith.
• Incipient decay allowed only where no softer than the surrounding wood.
• No knot checks wider than 1mm.
• Not more than two checks in any lineal metre. Checks to be no wider than 1mm.

Natural Feature grade

This grade allows a high level of natural feature. The expectation is that resin filler (e.g. epoxy) will be used to produce finished flooring.

Best (top) surface:

• Incipient decay allowed only where not softer than the surrounding wood. 
• Checks allowed where these are not found on more than 25% of the exposed top surface area.

Finger-jointed grade

Pieces to be jointed (shooks) shall be graded to meet structural requirements (under flooring over joists above). Shooks must be longer than 300 mm.

Jointed product lengths must be greater than 2 m and the top surface shall meet either Clears or Standard grades. 

The finger-jointed product shall be sold profiled and free of skip and wane. Grades specified shall be Clear Finger-jointed or Standard Finger-jointed.

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

General and Responsibilities

Rough sawn: If the consignment is graded rough-sawn the producer shall endeavour to try and meet the rules for the grade sold. However, the buyer should be aware that issues such as checking, collapse and skip cannot be graded for with accuracy on a rough-sawn product and the price agreed should reflect this.

Natural feature grade is a special grade of timber from which it is expected further selection and rejection of feature will be made to meet the requirements of the user. The level of feature required will dictate the percentage of the consignment used and the price agreed should reflect this appropriately.

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

Moisture content must be specified.
Note: Installation moisture contents should be around 10-12% for intermittently heated buildings and 8-10% for air-conditioned buildings. Regional variations also need to be taken into account. Drier areas such as Canterbury may require drier timber than humid areas such as Auckland. Consult your local flooring expert about local conditions.

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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Disclaimer: While every effort is made to ensure the accuracy of the information provided on this site, Farm Forestry Timbers Society do not accept liability for any consequences arising from reliance on the information published. If readers have any doubts about acting on any articles they should seek confirming, professional advice.