Joint groups

For timber joint design, timbers are classified into joint groups.

The six joint groups for seasoned (dry) timber are JD1 (highest) to JD6 (lowest). ‘88’ indicates the timber is non-structural so does not have a joint group; ‘—‘ indicates that density data were not available.

Joint groups for unseasoned (green) timber (J1 to J6) are given only where published, basic density data were available. Otherwise, ‘—‘ indicates that density data were not available.

For species groups, the joint classification uses the lowest joint-rated species in that group.

The structural use of timber requires adequate jointing and fastening procedures are applied in accordance with the joint design data and specifications presented in the AS 1684 series Residential timber—framed construction parts 2 and 3 (Standards Australia 2006), or AS 1720.1-1997 Timber structures—design methods (Standards Australia 1997).

Joint groups for seasoned and unseasoned timbers

Seasoned timber   Unseasoned timber   Joint group
JD1 J1 1
JD2 J2 2
JD3 J3 3
JD4 J4 4
JD5 J5 5
JD6 J6 6
88   non-structural timber, joint group not applicable
- - no reliable data
Last modified
02/13/2017 - 03:53