Treated Wood for Outdoor Use

When you are thinking about constructing a deck or outdoor structure, it is important that the type of wood being used for the project is considered. There are many types of wood to choose from, but treated wood is the preferred option. Treated wood is specifically designed to be able to withstand the elements of the outdoors. The treatment allows the wood to be more resistant to rotting and infestation of insects, which can occur over time.

Wood Treatment Process

The process of treating wood involves using a variety of different chemicals that are infused into the wood. These chemicals are designed are preservative in nature and help to allow the wood to last without showing signs of age. The lifespan of wood is extended substantially through the treatment process. Wood that is not treated before it is used for decking construction will wear down at a higher rate. The wood that is being treated is placed into a chamber with an airtight door that can be sealed. Once the door is sealed, water treated with chemicals is then forced into wood through the use of increased pressure within the chamber. This means that the preservative properties of the chemicals can be transferred to the wood.

Species and Treatment

Not all types and species of wood are ideal for exterior use. Even when treated, there are simply some species of wood that are more durable and resistant then others. This means that only the strongest types of wood are often  treated for exterior use. The most common types of wood that are treated and used for deck framing include Southern Pine and Douglas Fir. It is important to note that different species of wood can differ in the amount that they can cover as joists. This means that a span table must be considered when you are choosing a treated wood type and beginning construction on a decking structure.


Not only does the species of wood need to be considered before treatment, but grade is also a factor. The grade of wood refers to the quality. Different species of trees are known to have different grades. Grading of wood is done by inspectors with experience who know how to evaluate wood based on knots, decay, grain angles and signs of warping. Woods of a higher grade and higher quality are those that are better candidates for wood treatment and exterior use.

For more information, contact a local wood supplier like Australian Treated Pine