Defects In wood

• Seaming Intention


  To understand that timber has imperfections. To be able to identify and work with them
• Natural timber


  • It is a natural product and always has defects
  • Defects either weaken the wood or affect its appearance
• Sources of defects in timber

  • Natural defects
  • Defects which arise once the tree is cut down
• Defect


  An imperfection in the timber
• Natural timber can have defects that have occurred during the tree's growth

  1. Knots

  2. Dead/loose knot

  3. Live knot
• Live or tight knot

  • Not a problem, firmly retains its place in the surrounding wood
• Loose or dead knot


  • May fall out or may have already left a hole
• Defects which arise once the tree is cut down

  1. Bow

  2. Split

  3. Twist
• Bow


  A curve along the face of a board that usually runs from end to end
• Split


  Crack going all the way through the piece of wood, commonly at the ends
• Twist

  Warping where the ends twist in opposite directions
• Brown rot fungus causes cellulose degradation, resulting in brown discoloration and loss of strength.
• Fungi are the most common cause of decay in wood.
• Wood is susceptible to attack by fungi, insects, bacteria, and other organisms.
• White rot fungi cause both lignin and cellulose degradation, leading to white discoloration and complete decay.
• Insect infestations are common in tropical regions due to high temperatures and humidity levels.
• Fungi can be controlled by using preservatives such as creosote, pentachlorophenol (PCP), copper naphthenate, and chromated copper arsenate (CCA).