Timber Industry Terms

Question 1

Three types of visual grading

Answer 1

Building Grade (Merchant), Standard Grade (Engineering) and Select Grade (Clears)

Question 2

Building Grade (Merchant)

Answer 2

Timber which have many defects are classified into this grading, they are usually used where visual quality does not affect the project.

Question 3

Standard Grade (Engineering)

Answer 3

Timber which has some defects are defined as this grading.

Question 4

Select Grade (Clears)

Answer 4

Timber which only has a few defects are graded as this, unlike the building grade timbers timber categorized in this grading are used for quality finished work.

Question 5

Range of Stress

Answer 5

F2 - F34 (least - most)

Question 6

What are stress grades?

Answer 6

Stress grading gives the capacity of a piece of timber to support a load

Question 7

F4 (colour)

Answer 7

Red

Question 8

F5 (colour)

Answer 8

Black

Question 9

F7 (colour)

Answer 9

Blue

Question 10

F8 (colour)

Answer 10

Green

Question 11

F11 (colour)

Answer 11

Purple

Question 12

F15 (colour)

Answer 12

Orange

Question 13

F17 (colour)

Answer 13

Yellow

Question 14

F22 (colour)

Answer 14

White

Question 15

Example of timber graded F4 - F5

Answer 15

Radiata Pine

Question 16

Example of timber graded F5 - F8

Answer 16

Oregon

Question 17

Example of timber graded F11 - F34

Answer 17

Hardwood

Question 18

What are durability grades for?

Answer 18

Durability grading has to do with the resistance of timber from weathering.

Question 19

Class 1

Answer 19

Timber which are durable even when in continuous damp conditions. They normally have a 25-50 year of service lives expectancy.

Question 20

Class 2

Answer 20

Provided that timber is well ventilated, timber which are durable even though exposed fully to the weather. The service life expectancy is 15-25 years.

Question 21

Class 3

Answer 21

Timber which is durable in continuous dry conditions, have a 8-15 year expectancy.

Question 22

Class 4

Answer 22

Timber which only have a life expectancy of 1-8 years when in contact with ground is in class 4.

Question 23

Blockboard

Answer 23

This is built up with core of softwood strips and covered with sheet of plywood on each side (used for building material and furniture)

Question 24

Chipboard

Answer 24

This is made up of small chips of wood glued together and formed into sheets by compression (used in furniture but often covered with wood veneer or plastic laminate)

Question 25

Hardwood

Answer 25

This is made wood fibres that have been pulped, then put under pressure until fibres bond together. It becomes smooth on one side and rough on the other.

Question 26

Medium Density Fibreboard (MDF)

Answer 26

This is composed of fine wood dust and glue pressed into a board. (Used in building and furniture)

Question 27

Plywood

Answer 27

This is made from veneers (layers) of timber with each grain layer being at right angles to each other and glued together under pressure.