Construction Materials: Timber and Wood Products — CSEC Building Technology
Timber is a renewable, versatile building material. This topic covers types of timber, seasoning, defects and wood products.
Hardwood and softwood
- Hardwood comes from broad-leaved (deciduous) trees (e.g. mahogany, oak). Generally denser and more durable.
- Softwood comes from coniferous (cone-bearing) trees (e.g. pine, cedar). Generally lighter, cheaper and faster-growing.
Seasoning
Seasoning is the drying of timber to reduce its moisture content. Properly seasoned timber is more stable, stronger and less likely to warp or rot. Methods include air seasoning and kiln seasoning (faster).
Defects
- Warping — twisting, cupping or bowing caused by uneven drying.
- Knots — points where branches grew, which can weaken the timber.
- Splits and shakes — cracks along the grain.
Preservation
Preservation treats timber (e.g. with chemical preservatives) to protect it from decay (rot), fungi and insect attack, extending its life.
Manufactured wood products
Man-made boards use wood pieces and adhesive:
- Plywood — thin veneers glued with grains at right angles for strength.
- Chipboard and MDF — made from wood particles/fibres and resin. These are stable, available in large sheets and economical.
Exam tips
- Hardwood = broad-leaved trees; softwood = conifers.
- Seasoning = drying timber to reduce moisture.
- Know defects: warping, knots, splits.
- Plywood, chipboard, MDF are manufactured boards.