Design Aids

Table of Alternative Construction Timbers


Rating Description
Availability A Readily available
B Generally available
C Limited availability
D Only small quantities available
E Very limited supply
Suitability for use F Suitable heart or treated
G Suitable treated
H Suitable treated
I Suitable heart
J Not suitable, or not usually used
Grades suitable for building K No 1F and No 2F
L Framing
M No 1 and No 2 grading rules, unassigned strengths
N No grading rules and no assigned strength
Grading suitable for engineering uses O Grading rules and strengths
P Grading rules and no assigned strength
Q No grading rules but assigned strengths
R No grading rules and no assigned strength
Natural durability of heartwood S Perishable (5 years)
T Non-durable (5-10 years)
U Moderately durable (10-15 years)
V Durable (15-20 years)

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