Timber checks are splits or cracks that appear on the surface of wood as it dries and loses moisture.
Understanding Timber Checks
Wood is a natural material that contains moisture. As timber dries, especially after being harvested and milled, the moisture evaporates. This process of drying causes the wood fibers to shrink. However, shrinkage doesn't happen uniformly throughout the piece of timber. Different parts of the wood dry at different rates, leading to tension within the material.
According to the reference, wood checking and splitting is a natural phenomenon in timber, occurring as the wood dries and loses moisture. This natural process results in the formation of what are known as "checks."
Why Checks Occur
Checks are a direct result of the natural drying process. When the outer layers of the wood dry and shrink faster than the inner layers, stress is created. When this stress exceeds the wood's strength, it causes the surface fibers to separate, forming the characteristic splits or cracks.
Characteristics of Timber Checks
- Appearance: Checks typically appear as linear splits along the grain of the wood. They can vary in length and depth.
- Cause: Exclusively caused by the natural drying and moisture loss in timber.
- Structural Impact: Importantly, as noted in the reference, while they alter the appearance of the timber, checks also add unique character without affecting the wood's structural integrity. This means that a checked piece of wood is generally still strong and suitable for its intended structural purpose.
- Character: Many people view checks not as defects, but as features that add character and authenticity to wood, highlighting its natural origin and history.
Checks vs. Other Wood Defects
It's useful to differentiate checks from other potential wood issues:
- Checks: Caused by drying/moisture loss; typically do not affect structural strength.
- Splits: Can be more significant separations that go deeper or completely through the wood; sometimes caused by drying, but also mechanical stress or external forces; deep splits can affect structural integrity, unlike typical checks.
- Cracks: A general term often used interchangeably with checks, but can also refer to damage from impact or other causes.
Understanding checks is key for anyone working with natural timber, recognizing them as a normal part of the material's life cycle rather than a flaw.
