Timber is one of the most widely used natural construction materials, valued for its strength, durability, and aesthetic appeal. However, like all organic materials, timber is susceptible to a variety of defects that can compromise its structural integrity, durability, and appearance. Understanding these defects is essential for anyone involved in building construction and maintenance, as early detection and proper treatment can prevent serious structural problems and reduce maintenance costs over time. Defects in timber can broadly be classified into natural defects, seasoning defects, and defects caused by fungi, insects, or mechanical handling. Natural defects in timber arise during the growth of trees and are inherent to the wood itself. One of the most common natural defects is knots, which are portions of branches embedded in the wood. Knots can be classified as tight or loose, depending on how firmly they are attached to the surrounding wood. Tight knots may not significantly affect timber strength, but loose knots can weaken beams or boards, leading to potential structural failure. Another natural defect is shakes, which are separations along the grain of the timber. Shakes can occur due to rapid growth, climatic stress, or mechanical forces within the tree. They are classified into heart shakes, cup shakes, and star shakes depending on their location and pattern. Heart shakes, for instance, radiate from the center or heart of the timber and can severely reduce strength. Similarly, wane, which is the presence of bark or absence of wood along the edges, is often caused by irregular growth patterns and can affect the uniformity and strength of the timber. Growth stresses within timber can also produce defects such as bows, crooks, and twists. Bows refer to curvature along the length of a board, crooks are lateral bends along the edge, and twists occur when one end of the timber rotates relative to the other. These defects are usually caused by uneven growth or internal stresses in the living