Timber as a building material
TIMBER GRADING
Timber Grading is the process of segmenting timber’s natural variability into groups of set characteristics. Grading allows customers to define what they would like and timber producers the ability to outline what material they have available.
Characteristics critical for timber grading process
When grading timber material for appearance, there are two sets of criteria that are assessed:
The materials utility – is it fit for purpose?
It’s visual characteristics, these include; size and stability (dimensional regularity), durability (resistance to conditions), moisture content & performance characteristics.
The exact parameters of each of these characteristics are referred to as ‘Grade Definitions’ and, for Hardwoods, are outlined in Australian Standard 2796-2006.
How is timber graded?
There are three types of grading methods:
Visual Grading
Is performed by a trained assessor. This assessor visually inspects each piece of timber as it comes off the line and assigns a grade. This is the most common method of grading, especially when the intention of the piece is to be used for in an appearance application (ie. interior architecture).
Machine Grading
This type of assessment method utilises sensors or testing machines to compare the board against the criteria laid out in the grade definition. While it is quicker and more accurate than visual grading, we see it less common in practice as it is more expensive, and the machines require frequent calibration to ensure accuracy.
Proof Grading
An assessment method that is carried out only after other grading assessment methods have been complete. Mainly used on timber material that Proof Grading
An assessment method that is carried out only after other grading assessment methods have been complete. Mainly used on timber material that is to be used in a structural environment. This process involves testing the material for its strength & stiffness, by applying the loads set out in the grade definitions. If the material withstands these loads, then it passes. If it does not, then the machine is sent back for reprocessing.
Timber Grading is the process of segmenting timber’s natural variability into groups of set characteristics. Grading allows customers to define what they would like and timber producers the ability to outline what material they have available.
Characteristics critical for timber grading process
When grading timber material for appearance, there are two sets of criteria that are assessed:
The materials utility – is it fit for purpose?
It’s visual characteristics, these include; size and stability (dimensional regularity), durability (resistance to conditions), moisture content & performance characteristics.
The exact parameters of each of these characteristics are referred to as ‘Grade Definitions’ and, for Hardwoods, are outlined in Australian Standard 2796-2006.
How is timber graded?
There are three types of grading methods:
Visual Grading
Is performed by a trained assessor. This assessor visually inspects each piece of timber as it comes off the line and assigns a grade. This is the most common method of grading, especially when the intention of the piece is to be used for in an appearance application (ie. interior architecture).
Machine Grading
This type of assessment method utilises sensors or testing machines to compare the board against the criteria laid out in the grade definition. While it is quicker and more accurate than visual grading, we see it less common in practice as it is more expensive, and the machines require frequent calibration to ensure accuracy.
Proof Grading
An assessment method that is carried out only after other grading assessment methods have been complete. Mainly used on timber material that Proof Grading
An assessment method that is carried out only after other grading assessment methods have been complete. Mainly used on timber material that is to be used in a structural environment. This process involves testing the material for its strength & stiffness, by applying the loads set out in the grade definitions. If the material withstands these loads, then it passes. If it does not, then the machine is sent back for reprocessing.
