Kiln Dried Feature
As trees grow, their roots absorb moisture from the ground. The tree’s cells draw the water up the trunk to the limbs and leaves so that the entire tree benefits from the moisture. It is, therefore, the nature of tree cells to draw moisture from the air,
Drawing moisture from the air is a process that continues even after the tree has been cut down and used in a building. It is the nature of the wood to draw moisture to itself. In the winter, when the house is closed and heated, the wood dries and contracts. In the summer months when windows are open, the air in the house is like the air outside; therefore, the wood tends to draw moisture causing it to expand. For this reason, all of the moisture content of a tree should be removed before it is used as building material.
In order for lumber to be used, it must be dried. The process involves placing the wood in an oven known as a kiln. The temperature at which the kiln is set varies with the species of wood and its dimensions. If the temperature is too hot, the wood is likely to crack. If the temperature is too low, the moisture content is not sufficiently removed and the wood is likely to warp.
Humidity and air flow are controlled to permit the fastest drying rate for the species and its dimensions.. The time that it takes to dry the wood is also affected by species and dimensions. For example, oak must be dried slowly or it degrades. On the other hand, pine needs to be dried fast or it stains or molds.
Among the advantages of kiln drying are reduced weight, increased strength properties and additional resistance to deterioration due to fungi and insects. All of these are accomplished by precise measurements of those who operate the kiln to be certain that you have the best product available in building materials.
Conventional kilns are usually heated by steam or water coils. Sometimes the heat source may be a furnace, The heat removes the water from the wood and turns it into vapor. The vapor is exhausted from the kiln’s chamber. The conventional kiln produces good quality lumber when properly managed. Unfortunately, it is not energy efficient.