Softwood examples
- Redwood
- Pine
- Yew
- Spruce
- Cedar
- Douglas fir
- Larch
Softwood properties
- Takes 5-10 years to mature
- Mostly from northern hemisphere
- Known as conifers/evergreens
- fast growing (sustainable), can be regrown in a lifetime
- Straight trunks
- Careful forest management ensures worldwide demand is met
- Pine like leaves, produces cones
FSC
Forestry Stewardship Council
Hardwood examples
- Birch
- Beech
- Oak
- Mahogany
- Ash
- Maple
- Walnut
- Balsa
- Cherry
- Mangrove
- Acacia
- Holly
Hardwood properties
- Takes 150+ years to mature
- Grown across the world
- Broad-leafed, deciduous
- More durable than soft woods
- Variety of colour and texture (ebony-ash)
- Slow growing
- More expensive than soft woods
- Tighter grain
- Produces nuts and berries
- Holly is an exception as it’s evergreen with broadleaves
Faults in wood
- Grain
- Knots (not stable, very dense)
- Cupping (not dried properly or from heartwood)
- Bowing (not supported correctly)
- Twisting (not stacked correctly)
Biological attack
Insects
- woodlice, death watch beetle, woodworm
Fungi
- wet rot, stays at submerged area
- dry rot, moves up walls, not enough air
Conversion
Process of sawing logs into commercially viable timber
Slab sawn
- Wide planks
- Easy manufacture
- All timber used
- Cupping, unstable
- Cost effective
- Fast
Radial/Quarter sawn
- Thiner Planks
- More expensive
- Very stable
- Time consuming
- Cutting results in a good grain pattern
Seasoning
The process of removing excess water and much of the bound moisture from the cell walls. Water reduced to 20%. Immune to rot and decay
Kiln seasoning
Put in an oven (steam). Stream cures timber, vacuum draws water out. Takes 24hrs, quick and cheap
Natural air seasoning
Roof, no walls, air can circulate. Every 25mm takes one year to season. Expensive (time and space). High quality and very stable wood.
Manufactured board’s examples
- Chip board
- MDF (medium density fibreboard)
- Plywood
- Lamin board
- Block board
Lamination
Putting things into layers
Manufactured boards
Thermosetting plastic holds boards together (eg resin), not recyclable or sustainable, cost effective
Plywood
Strong, layers at 45 degrees, odd number of layers do grain runs the same way. +5 layers it is known as multiply
Advantages to manufactured boards
- 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
Disadvantages to manufactured boards
- 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
