Timber - Groups
- Timber or wood can be divided into 3 groups -
- Softwoods –Pines, spruces (xmas tree) Larches (spinney/tennis courts) Firs, Yew.
- Hardwoods - Oak, ash, beech, walnut, birch cherry, (Europe/GB) Teak, mahogany, walnut (exotic/hot countries)
- Manufactured boards – man made, chipboard, MDF, plywood, hardboard.
- Used mainly in construction industry.
- Generally softer than hardwoods but hard enough for roofs, stairs, frames, sheds etc.
- Quick growing trees so timber is cheaper than hardwoods.
- Most hardwoods are x2 of softwoods some x3.
- Softwoods grow mainly in temperate & cold climates – huge forests in Russia, Scandinavia & Canada.
- Grow in temperate & hot countries.
- Used for all types of furniture, church interiors, construction, musical instruments, ships interiors, veneers.
- More expensive than softwoods, some are extremely expensive( rarer varieties).
- Huge range of varieties.
Manufactured boards -
- Some are relatively cheap - chip, MDF & hardboard about the same as softwoods.
- Useful for large areas, doors, panels, backs, table tops, work surfaces etc.
- Generally stable materials.
- Often veneered with wood or plastic laminates – a relatively cheap wood enhanced to make it look expensive.
- Edges often need lipping.
Types of Manufactured Boards
Manufactured Boards –
Chipboard – Made of wood chips glued together under pressure – not waterproof.
MDF – made of glued wood fibres – not waterproof.
Both can be veneered.
Manufactured Board - Plywood
- Built up in layers with adjacent layers at 90° thus preventing splitting making it about x 20 stronger than ordinary timber.
- Can be veneered.
- Marine ply is waterproof.
- Thin layer of wood, often an expensive, exotic wood, peeled off a log (toilet roll).
- Used to enhance the appearance of manufactured boards to give upgraded/ expensive appearance.
- Rotary Cut Veneers: Quickest - Most veneer – Most economical – Least waste.
- Slice Cut Veneers: Best grain patterns – Matching patterns – most waste – more expensive.
Strength of Wood
- Knots in wood can weaken the structure and cause irregular grain making it difficult to work.
- Wood splits along the grain.
Defects of Wood
- Defects lower the value of timber.
- Distortion & splits occur mainly because of uncontrolled drying out of the wood.
- Timber will shrink when it dries & vice versa.
- Knots are natural defects.
- Warping, Bowing, Twisting, Cupping all occur on woods and affect the properties of Wood.
Structure of Timber
- Changing a log into usable timber:
- Slab sawing is the quickest & easiest method.
- Quarter/Radial sawing gives better quality timber, but is more expensive because it takes longer & there is more waste.
Laminate Flooring –
- A laminate is made up in layers.
- Kitchen/computer worktops are made of melamine.
- Formaldehyde then glued to a manufactured board base.
- Giving an enhanced, hardwearing material.