Timbers

Question 1

Soft wood examples

Answer 1

Redwood
Pine
Yew
Spruce
Cedar
Douglas fir
Larch

Question 2

Soft wood

Answer 2

• 5-10 years to mature
• mostly from northern hemisphere
• known as conifers/evergreens
• fast growing, sustainable as can be regrown in a life time
• straight trunks
• careful forest management ensures worldwide demand is met
• pine like leaves
• produces cones

Question 3

FSC

Answer 3

forestry stewardship council

Question 4

Hard wood examples

Answer 4

Birch
Beech
Oak
Mahogany
Ash
Maple
Walnut
Balsa
Cherry
Mangrove
Acacia
Holly

Question 5

Hardwood

Answer 5

• 150+ years to mature
• grown across the world
• broadleaves, deciduous
• more durable than soft woods
• variety of colour and texture, ebony-ash
• slow growing
• more expensive than soft woods
• tighter grain
• nuts and berries
• holly is an exception as it is evergreen with broad leaves

Question 6

Faults in wood

Answer 6

Grain
Knots
Cupping
Bowing
Twisting

Question 7

Knots

Answer 7

Not stable
Very dense

Question 8

Cupping

Answer 8

Not dried properly or from heart wood

Question 9

Bowing

Answer 9

Not supported correctly

Question 10

Twisting

Answer 10

Not stacked correctly

Question 11

Biological attack

Answer 11

Insects: woodlice, death watch beetle, wood worm

Fungi: wet rot (stays at submerged area), dry rot (moves up walls, not enough air)

Question 12

Conversion

Answer 12

Process of sawing logs into commercially viable timber.

Question 13

Slab sawn

Answer 13

Wide planks
Easy manufacture
All timber used
Cupping, unstable
Cost effective
Fast

Question 14

Radial/Quarter sawn

Answer 14

Thiner planks
More expensive
Very stable
Time consuming
Cutting results in a good grain pattern

Question 15

Seasoning

Answer 15

• process of removing excess water and much of the bound moisture from the cell walls.
• Reduced to 20%
• immune to rot and decay

Question 16

Kiln seasoning

Answer 16

Put in a steam oven
Steam cures timber
Vacuum draws water out
Takes 24hrs
Quick and cheap

Question 17

Natural air seasoning

Answer 17

Roof, no walls, air circulates
Every 25mm takes one year to season
Expensive
High quality and very stable

Question 18

Manufactured boards

Answer 18

Chip board
MDF
Plywood
Lamin board
Block board

Thermosetting plastic holds boards together. Not recyclable or sustainable but is cost effective

Question 19

MDF

Answer 19

Medium density fibre board

Question 20

Plywood

Answer 20

Strong, layers at 45 degrees
Odd numbers so grain runs the same way
More than 5 layers becomes multiply

Question 21

Advantages of manufactured boards

Answer 21

• large standard sized sheets
• uniform thickness
• stable in most atmospheric conditions
• grained boards have good strength to weight ratio
• thin sheets can be easily bent

Question 22

Disadvantages of manufactured boards

Answer 22

• difficult to join
• exposed edges often need to be hidden
• thin sheets become easily distorted, unless held in a frame
• adhesives can blunt cutting tools quickly