Wood has a number of outstanding characteristics:
- Thermal insulation
- Sound insulation
- High strength with good elasticity
- High resisting force under loads
- Easy workability
Due to the nature of timber, wood grain and the number of visible knots vary. Knots embedded in the wood are a common feature in timber based products.
Pressure treatment is a process that forces chemical preservatives into the wood. As the timber is placed in a pressure chamber, the preservatives are forced into the wood. The preservatives help protect the wood from all outdoor elements. Green and white spots are common in pressure treated wood and can be brushed off easily.
Like many natural materials, the cells in wood contain water. Depending on the humidity in the air, this moisture is gradually released and/or absorbed and results in the changes in volume. This can result in timber shakes (splits). The shakes will expand and retract as moisture reacts with the core timber.
Each tree is unique. Its shape, colour and wood grain retain their uniqueness after processing. Wood varies in density. Therefore, it does not uniformly absorb the chemical preservatives when pressure treated, resulting in colour variations. Over time, variations in colour will disappear when the wood is exposed to sunlight.
Because of the varying density of wood and its texture, swelling and shrinking as described above does not occur uniformly. This can result in cracks or warping, which do not affect the structural characteristics and strength of the wood.