Preparation & Use of Pressure Treated Wood

Softwood requires treatment or else insects and moisture will destroy it. The industry workaround is treating it with chemical preservatives. These are traditionally applied by hand or by soaking. However pressure treated wood is more permanent and therefore worth the additional cost.

Pressure treatment ensures a more uniform application that extends the life of the product. Moreover, the process takes place in a controlled environment as the material rolls in giant pressurized tanks. This is the chosen method for extending the life of softwood structural timbers, ties and poles in permanent installations.


Things to Know Before Working with Pressure Treated Wood


The degree of protection depends on how long the lumber was exposed to the preservative. Before purchasing, check whether the wood is suitable for ‘above ground use only’ or whether it can be on, or in the ground

The Canadian Government recommends alkaline copper quaternary (ACQ) or copper azole (CA-B) for residential projects. However chromated copper arsenate is no longer available because it is not environmentally unfriendly.


# Always wash – especially children’s hands after touching treated wood

# Use a table cloth to prevent food touching pressure treated wood

# Do not burn the material because this releases chemicals to the environment


Tips for Working with Pressure-Treated Wood


Check the label or stamp on the material. The number is the minimum amount of preservative the wood absorbed. A higher number indicates more pounds weight of chemical per cubic foot.

There’s still confusion lingering over this, because alkaline copper quaternary and copper azole are more effective than chromated copper arsenate per unit of weight. That’s because they contain higher levels of copper and are therefore more corrosive.

That is in turn why treated lumber manufacturers recommend hot-dipped galvanized, or stainless steel nails, screws, bolts, etc. when working with pressure treated wood. Vinyl or copper flashing is preferred over metal unless the wood has a protective membrane.

Ff you are doing the job yourself, do remember to drill a pilot hole before driving in a screw or nail. That’s because were this to split the wood, then moisture and insects could penetrate beyond the reach of the chemicals.


A Last Few Words for Safety’s Sake


Work outside wearing gloves, safety goggles, and face mask when cutting or sanding pressure treated wood. Avoid burying off cuts, scrap and sawdust. Take these to a recycling plant instead. Treated wood has been a boon for the construction industry. That’s unfortunately because it contains chemicals harmful to some forms of life.

Valiant Exteriors provides this information in the general public interest. Hence this article does not constitute statutory health and safety advice.

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