Stress grades table

Use the strength groups table to determine if a timber could meet specified stress grades.

Strength groups: S1 and SD1 are the strongest strength groups for unseasoned and seasoned timber respectively.

Stress grades: Higher F ratings are given to stronger boards.

Structural grades: Structural 1 can achieve the highest stress grade.


Stress grades & visual grades in relation to strength group for seasoned (SD) and unseasoned (S) timber*

1. Seasoned timber

Strength group

SD1

SD2

SD3

SD4

SD5

SD6

SD7

SD8

 

high

low

Visual grades

Stress grades

Structural 1

F34

F34

F27

F22

F17

F14

F11

F8

Structural 2

F34

F27

F22

F17

F14

F11

F8

F7

Structural 3

F27

F22

F17

F14

F11

F8

F7

F5

Structural 4

F22

F17

F14

F11

F8

F7

F5

F4

Softwoods only -
Structural 5**

F7

F5

F4

 

 

 

 

 

 

 

 

 

2. Unseasoned timber

Strength group

S1

S2

S3

S4

S5

S6

S7

SD8

 

high

low

Visual grades

Stress grades

Structural 1

F27

F22

F17

F14

F11

F8

F7

Structural 2

F22

F17

F14

F11

F8

F7

F5

Structural 3

F17

F14

F11

F8

F7

F5

F4

Structural 4

F14

F11

F8

F7

F5

F4

Softwoods only -
Structural 5**

F7

F5

F4

Source: AS 2878-2000 Timber—classification into strength groups (Standards Australia 2000).

* This table does not apply to white cypress (Callitris glaucophylla), which has equivalent strength properties in seasoned and unseasoned conditions, with available stress grades: F7, F5 and F4.

** The visual grade ‘Structural 5’ only applies to softwoods (e.g. Pinus, Picea, Larix, Araucaria and Abies species).

Last modified
02/23/2017 - 04:04